def:
AIRFOIL- surface desiganted to obtain a desired REACTION FORCE (ex lift)
ANGLE OF INCIDENCE- angle formed by CHORD LINE and LONGITUDINAL
ATTITUDE- PITCH angle + BANK angle
CENTER OF GRAVITY- point at which plane would balance
CENTER of PRESSURE- point along the CHORD LINE of WING at which all aerodynamic forces are concentrated = CENTER OF LIFT (CHORD-intersection bewteen LIFT and DRAG)
DIHEDRAL- point where wings are slanted upwardsfrom wing root to tip (WASHOUT and SWEEPBACK)
WASHOUT- whereANGLE OF INCIDENCE less at tip than root
SEEPBACK- angle where wings are slanted rearward from root to tip
RELATIVE WIND- direction of AIRFLOW opposite to FLIGHT PATH
STALL- loss fo LIFT + increase in DRAG where ANGLE OF ATTACK > ANGLE OF LIFT (CRITICAL ANGLE OFATTACK)
WING: WING AREA + WING PLANFORM (TAPERED [leading/ trailling edges], DELTA, STRAIGHT [leading/trailing edges], SWEPTBACK.
SPPED- DISTANCE travelled at a given time
VELOCITY- rate of movement on certain direction
VECTOR- direction (VELOCITY) + MAGNITUDE of a force ex: the center of pressure or the CHORD intersection between LIFT and DRAG)
ACCELERATION- changing SPEED or changing DIRECTION (ex: pivot turns around a point- plane accelerates even if at same SPEED because DIRECTION is changing)
THE PLANE
TYPES OF FUSELAGE- TRUSS (skin is supported by a web framework); MONOCOQUE (bulkhead) and SEMI-MONOCOQUE (skin reinfroced by longerons or bulkheads)
WINGS- are AIRFOILS attached to the FUSELAGE: SEMI-CANTILEVER attached both by external (struts) and internal (spars and ribs) ex high wings plane; CANTILEVER where stress is carried by internal wings spars, ribs ex low wing.
WINGS include AILLERONS, FLAPS and FUEL TANKS
ENPENNAGE- VERTICAL STABILIZER (DIRECTIONAL STABILITY/ YAW) and HORIZONTAL STABILIZER (LONGITUDINAL STABILITY/ PITCH)
Landing gear: for tailwheels and nosewheels either fixed or retractable
THE 3 AXIS OF ROTATION
1) LATERAL – rotation about LATERAL is called PITCH- controlled by ELEVATOR (called LONGITUDINAL STABILITY) like a seesaw
2) LONGITUDINAL- rotation about LONGITUDINAL is called ROLL- controlled by AILLERONS (called LATERAL STABILITY) like rotisserie
3) VERTICAL- rotation about VERTICAL is called YAW -controlled by RUDDER (called DIRECTIONAL STABILITY)
FLIGHT CONTROLS
PRIMARY FLIGHT CONTROLS (ATTITUDE)- airfoils attached to trailing edges of wings and VERTICAL and HORIZONTAL STABILIZERS- when deflected they change the camber of angle of attack of wing or stabilizer and so change LIFT/DRAG
ELEVATOR (rear of HORIZONTAL STABILIZER) controls PITCH: NEGATIVE ANGLE of ATTACK on wings or NEGATIVE STABILITY = downward tail force or raise elevator; POSITIVE STABILITY= forward pressure on yoke, tail rises and decrease nose PITCH and ANGLE OF ATTACK on wings
AILLERONS (to control ROLL/BANK)- AILLERON lowered= INCREASE ANGLE OF ATTACK on that wing (+DRAG – LIFT); AILLERON raised = DECREASE ANGLE OF ATTACK (-DRAG + LIFT)
AILLERONS produce HORIZONTAL LIFT (wings lift sideways and up conteract INERTIA, pulling plane straigh ahead); VERTICAL LIFT
RUDDER (rear of VERTICAL STABILIZER) controls YAW- protrubes into airflow, causing horizontal force in opposite direction: pushing tail to one direction and yaw nose to opposite)
SECONDARY FLIGHT CONTROLS: TRIM (small airfoils recessed into trailing edges of primary controls, moving in opposite direction to the later: ELEVATOR requires UP DEFLECTION, TRIM TAB DOWN to relieve back pressure);
FLAPS: slower landing speed (less landing distance); comparatively steep angle of descent without increase of speed- heps clear obstacles on short runway-; shorten take off distance – steeper climbing path-. CHANGE CHORD LINE ANGLE OF ATTACK and CAMBER
SLATS (delay airflow separation) and SPOILERS (upper surface of wing)
FORCES ACTING ON A PLANE
1- LIFT- (perpendicular to flight path through wings CENTER OF LIFT). The 3 main AIRFOILS are on WING, PROPELLER, HORIZONTAL TAIL surfaces. Depends on SPEED, ANGLE OF ATTACK, PLANFORM OF WING, WING AREA, AIR DENSITY.
WEIGHT- acts VERTICALLY DOWNWARDS through CENTER OF GRAVITY
THRUST- acts PARALLEL to LONGITUDINAL AXIS
DRAG- acts REARWARD and PARALLEL to RELATIVE WIND
(FROST)
STEADY UNNACELERATED FLIGHT-all 4 are in equilibrium (same DIECTION, same MAGNITUDE)
When pressure applied one/more controls- from STEADY FLIGHT (ex: increasing THRUST, MAINTAINING ALTITUDE= plane ACCELERATES>SPEED, >DRAG until a point that DRAG=THRUST and plane is back to STEADY FLIGH at HIGHER SPEED)
LIFT
BERNOUILLI’s PRINCIPLE- “internal pressure of fluids decreases at points where speed of fluids increases”- because of CAMBER
air flow travels a GREATER DISTANCE on UPPER LEVEL OF WING FASTER than airflow on LOWER WING SURFACE, therefore PRESSURE is LESS than in bellow wing , generating LIFT FORCE OVER CURVED SURFACE of wing.
NEWTON’s THIRD LAW OF MOTION- “for every action force, there’s an equal and opposite reaction force”
due to ANGLE OF INCIDENCE and ANGLE of ATTACK, LOWER SURFACE deflects air DOWNWARD (action) which causes an UPWARD force (reaction)- both contribute to LIFT
WEIGHT- (GRAVITY accelerates mass of plane downward VERTICALLY). The CENTER of GRAVITY is on LONGITUDINAL AXIS NEAR BUT FORWARD THE CENTRE OF LIFT of the wing(depends on location of LOADS).
Determined by WEIGHT/BALANCE calculations , the LOCATION of the C.G. determines the plane’s STABILITY and PERFORMANCE (in its relation to CENTER OF LIFT)
In a STRAIGH and LEVEL flight, UNNACELERATED flight, plain neither gains nor looses ALTITUDE (LIFT=WEIGHT)
THRUST
FORWARD FORCE- receives power from engine and displaces air to rear. For CONSTANT AIR SPEED- THRUST and DRAG must be EQUAL
DRAG
REARWARD FORCE- resulting from FORWARD movement of plane through the air , ACTS PARALLEL and SAME DIRECTION as RELATIVE WIND
INDUCED DRAG vs PARASITE DRAG
INDUCED DRAG- when wing produces LIFT, LOWER SURFACE has MORE PRESSURE THAN UPPER WING, so air flows from HIGH to LOW and EQUALIZES at WINGTIP, flowing OUTWARD from UNDERSIDE TO UPPERSIDE. the lateral flow imparts a ROTATIONAL VELOCITY to the air at wingtips and TRAILS behind wings- 2 VORTICES that move FORWARD (counterclockwise about right wingtip and clockwise about the left)
This ‘INDUCES` :
1- UPWARD FLOW beyond wingtip
2- DOWNWASH flow on and behind the trailing edge (different from downwash of lift). The DOWNWASH bends LIFT VECTOR REARWARDS (lift becomes slightly AFT of PERPENDICULAR to the RELATIVE WIND)
AS ANGLE OF ATTACK INCREASES = greater NEGATIVE PRESSURE on top of the wing= greater INDUCED DRAG
THE SLOWER THE AIRSPEED= the greater the ANGLE OF ATTACK to produce LIFT= the greater the INDUCED DRAG
INDUCED DRAG is INVERSELY THE SQUARE of AIRSPEED (ex: reducing from 120mph to 60mph = 4x’s induced drag)
PARASITE DRAG-
a) FORM DRAG (nose)
b) SKIN DRAG (structure)
c) INTERFERENCE DRAG (intersections of fuselage/tail and wings)
FACTORS:
1) the MORE STREAMLINED the object the LESS PARASITIC DRAG
2) the MORE DENSE the air the GREATER the PARASITIC DRAG
3) the LARGER the size of the object the MORE PARASITIC DRAG
4) SPEED INCREASES , PARASITIC DRAG INCREASES: SQUARE OF VELOCITY (speed doubled times square the drag)
FROST when TEMPERATURE < DEW POINT < FREEZING; FROST disrupts the smooth airflow: DECREASES LIFT, INCREASES FRICTION + DRAG
DYNAMICS OF AN AIRPLANE IN FLIGHT
LIFT= ANGLE OF ATTACK xs AIRSPEED (angle of attack on airspeed increase= + LIFT)
THERES ONLY ONE ANGLE OF ATTACK PER AIRSPEED (airspeed increases, angle of attack has to increase and vice versa)
+ LOAD= > ANGLE OF ATTACK to keep SAME AIRSPEED
DRAG/ ANGLE OF ATTACK/ AIRSPEED:
http://en.wikipedia.org/wiki/File:Drag_Curve_2.jpg
AIRSPEED DECREASES =ANGLE OF ATTACK INCREASES= + INDUCED DRAG
As AIRSPEED DECREASES PARASITIC DRAG DECREASES
LEVEL FLIGHT- the intersection (LIFT/DRAG optimum) or DRAG=THRUST (+THRUST = CLIMB except if TRIMMED for LOWER ANGLE OF ATTACK and higher AIRSPEED)
LIFT/DRAG MAX (optimum) = least amount of THRUST for LEVEL FLIGHT i.e. MAX GLIDE SPEED or POWER OFF GLIDE RANGE
PITCH/ POWER/ PERFORMANCE (THRUST vs DRAG)
CLIMB= + THRUST or +NOSE/ ANGLE OF ATTACK
+ thrust =+ speed = – angle of attack
-thrust = – speed = +angle of attack
SLOW FLIGHT (any speed from below cruise to stall)
on STRAIGHT LEVEL- LIFT= WEIGHT and THRUST= DRAG
in SLOW FLIGHT – THRUST no longer same as DRAG
2 components of SLOW FLIGHT:
1) Perpendicular to flight path
2) along flight path
http://www.av8n.com/how/htm/4forces.html
The Four Forces — Climb
Inclined Thrust has to be bigger than drag
http://www.av8n.com/how/htm/4forces.html
The Four Forces — Low Speed Descent
Wing Lift less because Vertical component of Thrust helps support plane
http://www.av8n.com/how/htm/4forces.html
The Four Forces — High Speed Dive
VME-Maximum Speed Endurance
Airspeed decreases from Cruise to L/D MAx (Glide) – Thrust and Drag optimum to maintain altitude with the LOWEST FUEL CONSUMPTION for LEVEL FLIGHT= SPEED FOR MAXIMUM ENDURANCE (VME)
Flight at bellow VME requires MORE POWER (not less) to keep same altitude or steady level flight, its the BACKSIDE of THE POWER CURVE or REGION of REVERSE COMMAND
when flying AT BELOW VME avoid natural tendency to pulling back on elevator because >ANGLE oF ATTACK= > DRAG= STALL (if CRITICAL ANGLE OF ATTACK exceeded)
MCA- Minimum Controllable Airspeed
INCREASE ANGLE OF ATTACK/LOAD FACTOR or REDUCTION OF POWER (maintaining same altitude)= STALL
in SLOW FLIGHT DONT INCREASE ANGLE OF ATTACK TO CLIMB, USE POWER AND LOWER NOSE
GROUND EFFECT: (The closest to the ground the biggest effect, mostly on LOW WING PLANES)
changes the aerodynamic characteristics of the wing
WING requires LESS ANGLE OF ATTACK to produce SAME AMOUNT OF LIFT (maintain angle and lift will result)
Alters THRUST vs VELOCITY : REDUCED INDUCED DRAG (low airspeeds)
REDUCED THRUST
NO EFFECT ON PARASITIC DRAG
TAKE OFF- requires higher angle of attack to maintain same amount of lift
increase in induced drag and thrust
decrease in stability (slight nose up pitch)
LANDING (opposite effect from the off)- allows for lift off ground at lower airspeeds (SECURE SAFE AIRSPEED BEFORE TAKE OFF RUNWAY); FLOATING tendency when excessive airspeeds
HOW AIRPLANES TURN:
BANK- VERTICAL LIFT- counter acts WEIGHT and GRAVITY
BANK- HORIZONTAL LIFT- counter acts INERTIA
without bank, tendency to remain level (inertia)- it pulls plane away from the turn when a plane turns
ADVERSE YAW: when applying ailleron to bank (turn)- RISING WING (LOWERED AILLERON) PRODUCES GREATER LIFT and GREATER DRAG- this increased drag tends to push the plane TOWARDS HIGH WING AGAINST THE TURN
COORDINATED TURN: so, RUDDER must be used simultaneously to AILLERONS in the DESIRED DIRECTION OF THE TURN
Plane in coordinated turn flies PARALEL (opposite to) RELATIVE WIND, not sideways (about vertical axis), and so its turning at an appropriate rate to its angle of bank; once at desired bank, pilot neutralizes aillerons and rudder.
CONCLUSION: there’s LESS VERTICAL LIFT in A BANK THAN IN STRAIGHT LEVEL, so to MAINTAIN ALTITUDE in A TURN INCREASE BACK PRESSURE and /or INCREASE POWER
TORQUE: increases in direct proportion to engine power and attitude, inversely with airspeed.
HIGH ANGLE OF ATTACK= > TORQUE
POWER HIGH= > TORQUE (ex: take offs, landings)
3 types:
1) CLOCKWISE COUNTER REACTION- fuselage goes left against nose
2) GYROSCOPIC PRECESSION (raise tail)- more on tailwheels
3) SLIPSTREAM ( vertical stabilizer “corckscrew” to the right)
4) P-FACTOR (ascending vs descending blade in the propeller- assymetrical loading of blades)
AIRPLANE STABILITY:
a) MANEUVERABILITY- stable plane will return to its original position after equilibrium disturbed (ex: turbulence), sometimes may require control correction
b) CONTROLABILITY – respond to pilot control
STABILITY- STATIC - initial tendency shown by the plane after equilibrium disturbed
STATIC STABILITY: POSITIVE, NEUTRAL and NEGATIVE
STATIC POSITIVE (most desireable) return to original trimmed altitude
STATIC NEUTRAL
STATIC NEGATIVE
DYNAMIC STABILITY- overall tendency after equilibrium is disturbed AFTER INITIAL (or STATIC) tendency
DYNAMIC STABILITY: POSITIVE, NEUTRAL And NEGATIVE
POSITIVE STATIC/DYNAMIC POSITIVE (Damped Oscilation)- “Displacement”- overall tendency to RETURN to original attitude
through series of DECREASING OSCILATIONS
POSITIVE STATIC/DYNAMIC NEUTRAL (Undamped oscilation) -attempt to return to original but OSCILATIONS DONT INCREASE NOR DECREASE as time passes
POSITIVE STATIC/NEGATIVE DYNAMIC- overall tendency of plane to attempt to return to original attitude but OSCILATIONS INCREASE in MAGNITUDE over time
MOST DESIREABLE: POSITIVE STATIC and POSITIVE DYNAMIC
1- LONGITUDINAL STABILITY: About LATERAL AXIS- determines PITCH TO STALL- location of CENTER of GRAVITY to CENTER of LIFT
The more LONGITUDINAL STABILITY the LESS MANEUVERABILITY: The closest the CG to the CL the less stable becomes the plane
POSITIVE LONGITUDINAL- CL BEHIND CG
NEUTRAL LONGITUDINAL- CL At CG
NEGATIVE LONGITUDINAL- CL in FRONT of CG
Most planes: NOSE DOWN TENDENCY (natural tendency to pitch downward away from stall)- POSITIVE LONGITUDINAl STABILITY (CL BEHIND CG)
NOSE DOWN TENDENCY is offset by HORIZONTAL STABILIZER (an inverted airfoil with camber on the bottom) and the downwash on wings and propeller
1) LESS SPEED: less tail downwash= DECREASE in DOWNWARD FORCE on HORIZONTAL STABILIZER= NOSE PITCH DOWN
2) SPEED INCREASE: in the NOSE LOW ATTITUDE (because in straight and level it would generate a `inverted control region`) TAIL DOWNWASH on HORIZONTAL STABILIZER INCREASES (tail pushed down)
–> if plane has POSITIVE DYNAMIC STABILITY: oscilations decrease until downward tail force is equal to a nose down attitude WITH DECREASE OF SPEED And the Opposite with INCREASE of SPEED
Some planes have THRUST LOWER THAN CG (propeller provides nose up pitching force to overcome the nose heaviness).
Common Miss conception: LONGITUDINAL STABILITY is NOT in respect to HORIZON: there’s only ONE SPEED PER ANGLE OF ATTACK (DEGREE), plane will eventually stabilize (EQUILIBRIUM) at the angle of attack/speed at which plane is trimmed for.
2) LATERAL STABILITY about LONGITUDINAL AXIS: stability over ROLL (when one wing is lower than the other)
4 factors that influence lateral stability:
a) DIHEDRAL- angle between wing and imaginary line parallel to lateral axis. On a GUST , one wing rises while the other lowers, making the plane bank/roll without turning, sliding towards the low wing
Because of DIHEDRAL winds hit low wing at higher angle of attack than higher wing, which restores wings to level altitude. It produces a rolling moment to return plane to a laterally balanced condition.
b) SWEEPBACK- angle at which wings are slanted rearward from root to wing tip
it also places CENTER OF LIFT farther REARWARD (affecting LONGITUDINAL MORE THAN LATERAL STABILITY)
it also affects DIRECTIONAL (YAW) STABILITY
basically same effect as DIHEDRAL
c) KEEL EFFECT (fuselage and vertical stabilizer: greater surface is ABOVE and BEHIND CENTER OF GRAVITY, so against pressure of airflow rolls plane back to level)
d) WEIGHT AND DISTRIBUTION- plane rolls towards the wing with more fuel
LATERAL STABILITY in TURNS:
SHALLOW (<30 degrees)- recovers automatically
MODERATE (between 30 degrees and 45) the WING on the OUTSIDE travels FASTER nearly canceling the stabilizing effect of lateral stability- TENDS TO HOLD THE BANK
STEEP- (over 45 degrees)- INCREASED LIFT on the OUTSIDE WING OVERCOMES planes LATERAL STABILITY and REQUIRES OPPOSITE AILLERON pressure to prevent overbanking- RATE OF TURN VARIES WITH AIRSPEED (ex: a 30 degreeturn is stable at 100 knts)
3) DIRECTIONAL STABILITY ABOUT VERTICAL AXIS- accomplished by vertical stabilizer causing plane to turn into relative wind
if plane yawed out of a straight level or turn, the relative wind is going to push the vertical stabilizer and return plane to original direction of flight.
SWEEPBACK- also aids DIRECTIONAL STABILITY: causes “Leading wing” to present more frontal area to the relative wind then trailing wing
FORWARD SLIP- fuselage provides a broad area for the relative wind to strike, helping fuselage to paralel relative wind (more YAW STABILITY)
EFFECTS OF LATERAL and DIRECTIONAL STABILITIES:
UNDESIREABLE:
DUTCH ROLL- combination of rolling/yawing oscilations caused by gusts in turbulent air.
When equilibrium is disturbed. ROLLING PRECEEDS YAW: when plane rolls back to flight level due to dihedral, rolls back too far and sideslips the other way. Each oscilation overshoots wing level attitude (sort of like the negative dynamic stability oscilations).
If the DUTCH ROLL is not decreased by DIRECTIONAL (YAW) STABILITY, becomes objectionable. So to counteract the DUTCH ROLL EFFECT, planes are designed to INCREASE DIRECTIONAL STABILITY and DECREASE LATERAL STABILITY- together these may cause tendency to spiral (SPIRAL INSTABILITY: when directional stability is much too stronger over lateral). Because SPIRAL MOTION is SLOW and CONTROLLABLE, its LESS OBJECTIONABLE THAN DUTCH ROLLS.
On a side slip, STRONG DIRECTIONAL STABILITY YAWS NOSE BACK INTO ALIGNMENT WITH RELATIVE WIND AND THE COMPARATIVELY WEAK DIHEDRAL LAGS IN RESTORING THE LATERAL BALANCE. So outside wing travels faster, increasing lift, increasingly over banking, at the same time the nose on alignment with relative wind is forcing nose at lower pitch attitude.
LOAD and LOAD FACTORS- its any force to deflect a plane from straight
LOAD FACTOR= TOTAL LOAD SUPPORTED BY WINGS
TOTAL WEIGHT OF AIRPLANE
ex: LOAD FACTOR 2 or a ratio to the pull of gravity (“G”)- weight of a plane = 1 G in un accelerated flight or the total LIFt on WINGS= TOTAL GROSS WEIGHT of PLANE
> ANGLE OF ATTACK and constant airspeed = > LIFT and > LOAD FACTOR
POSITIVE LOAD- back elevator causing CENTRIFUGAL FORCE to act SAME DIRECTION as WEIGHT
NEGATIVE LOAD- forward elevator pressure causing CENTRIFUGAL to act in OPPOSITE DIRECTION of WEIGHT
LOAD FACTORS and AIRPLANE DESIGN
to be certified by FAA the max allowable LOAD FACTOR LIMIT of planes is standard by classification according to the strength/operational use
CATEGORY:
NORMAL (permissible maneuvers: any incidental to normal flying- stalls, lazy eights, chandelles, steep turns under 60 degrees)- max LOAD of 3.8 POSITIVE and 1.52 NEGATIVE G’s
UTILITY(permissible: all operations spins if placarded, angles not exceeding 60 degrees) MAX LOAD of 4.4 POSITIVE and 1.76 NEGATIVE G’s
ACROBATIC (no restrictions) MAX POSITIVE LOAD of 6G’s and NEGATIVE of 3.0 G’s
EFFECTS OF TURNS on LOAD FACTORS
HORIZONTAL LIFT- in a constant altitude/ coordinated turn the resultant load is GRAVITY + CENTRIFUGAL
SAME LOAD if ALTITUDE is constant for a given degree of bank
SAME LIFT regardless of speed and rate of turn
WINGS MUST PRODUCE LIFT to= (EQUAL) LOAD TO MAINTAIN SAME ALTITUDE
http://www.aerospaceweb.org/question/performance/q0146.shtml
The LOAD FACTOR INCREASES EXPONENTIALLY IF ANGLE OF BANK REACHES 50 DEGREES
http://www.aerospaceweb.org/question/performance/q0146.shtml
http://ma3naido.blogspot.com/2008/11/load-factors-and-stalling-speeds.html
By banking the airplane to just beyond 72° in a steep turn produces a load factor of 3, and the stalling speed is increased significantly. If this turn is made in an airplane with a normal unaccelerated stalling speed of 45 knots, the airspeed must be kept above 75 knots to prevent inducing a stall. A similar effect is experienced in a quick pullup, or any maneuver producing load factors above 1 G. This has been the cause of accidents resulting from a sudden, unexpected loss of control, particularly in a steep turn or abrupt application of the back elevator control near the ground.
EFFECT OF LOAD FACTOR ON STALLING SPEED
At given AIRSPEED LOAD FACTOR INCREASES as ANGLE OF ATTACK INCREASES
CRITICAL ANGLE= STALL- there’s a direct relation between LOAD FACTOR imposed on a wing and its stalling charcteristics.
PLANE STALL SPEED DOUBLES in PROPORTION TO SQUARE FOOT OF LOAD FACTOR
ex: using LOAD FACTOR G’s vs STALL AIRSPEED: a plane with a normal un accelerated stall speed of 45 Knts (1G), will stall at 90Knts if submited to a LOAD of 4G’s.
DESIGN MANEUVERING SPEED (VA)
Max speed at which a plane can be stalled without exceeding strucutural (LOAD) limits
VA varies with GROSS WEIGHT (decreases with weight)- thats why its not on the Airspeed Indicator; it may be placared or else on the POH
Its also calculated by MULTIPLYING 1.7 TIMES NORMAL STALLING SPEED (ex: VS1 49 knts- 49×1.7=83.3- plane should never be stalled over 83.3knts). Lighter planes are subject to more rapid acceleration from turbulence/ gusts and therefore have a LOWER STALLING SPEED than a heavier plane , thus a LOWER VA.
Theoretically, a damaging POSITIVE flight LOAD CANNOT BE PRODUCED BELLOW VA (plane should stall before that happens) but GUST/WIND SHEARS may do it.
EFFECT OF TURBULENCE on LOAD FACTOR
1)turbulence in the form of VERTICAL AIR CURRENTS may cause severe LOAD STRESS on a plane’s wing (RELATIVE WIND changes UPWARD when meeting the airfoil, INCREASING ANGLE OF ATTACK of WING).
2)GUST LOAD FACTORS INCREASE WITH INCREASING AIRSPEED
In severe turbulence (rough air, thunderstorms or FRONTAL CONDITIONS) : Fly < VA! - (this is the least likely airspeed to result in strucutral damage while allowing margin of safety above stalling speed in turbulence)
V-G DIAGRAM (VELOCITY vs G-LOADS)
http://www.paragonair.com/services/tests/800partbgeneralairplaneops/_answer8.php
Each plane has its own VG for a specific ALTITUDE and WEIGHT.
On the graph, THE CURVED LINES (max amount of LIFT on a specific speed)
Since the maximum load factor varies with the square of the airspeed, the maximum positive lift capability of this airplane is 2 “g” at 92 m.p.h., 3 “g” at 112 m.p.h., 4.4 “g” at 137 m.p.h., and so forth. Any load factor above this line is unavailable aerodynamically.- for the Festival POSITIVE LIFT max is +3.8 and NEGATIVE is -1.52 and the “ULTIMATE LOAD FACTOR” is + 5.76 and -2.286 (structure doesnt fail but causes damage)
On the graph, THE INTERSECTION POINT is the intersection of the positive limit load factor [upper curved line] and the line of maximum positive lift capability [horizontal top of green envelope]. The airspeed at this point is the minimum airspeed at which the limit load can be developed aerodynamically. Any airspeed greater than this provides a positive lift capability sufficient to damage the airplane; any airspeed less does not provide positive lift capability sufficient to cause damage from excessive flight loads
The stall acts as a safety valve, insuring that the airplane stops flying before it can generate overstressful load on the airframe. If the aircraft was flying faster it could make more total lift, which could exceed the permissible ratio of TOTAL LIFT ÷ AIRCRAFT WEIGHT.
If you REDUCE WEIGHT ===> REDUCE LIFT to maintain load limit.
To REDUCE LIFT ===> REDUCE AIRSPEED; Va for this weight.
If you REDUCE WEIGHT ===> REDUCE Va.
In smooth air and wings level- the speed at which the wings stall at 1G is VS1 aprox 60MPH (lower limit of the green arc in the Festival)- any point ABOVE VS1 is ACCELERATED STALL
VA- (DESIGN MANEUVERING SPEED)- at SPEEDS GREATER than VA the LIMIT LOAD FACTOR will be exceeded so plane will STALL
VNO- (MAX STRUCTURAL CRUISING SPEED)- upper limit of GREEN ARC
VS1 to VNO- NORMAL OPERATING RANGE (above that only in smooth air and with caution)
VNE- NEVER EXCEED SPEED (RED LINE)
VNO to VNE-YELLOW ARC
Always factor VERTICAL WINDS and GUSTS (causes increase in angle of attack= increase in load factor)
Always factor FLIGHT ENVELOPE (the diagram) POSITIVE and NEGATIVE LIMIT LOAD
Factor VNE
STALS and SPINS:
STALL- is a loss of Lift or increase in drag when aircraft exceeds critical angle of attack
STALL SPEED- speed at which critical angle of attack is exceeded
CRITICAL ANGLE OF ATTACK- when the AIRSTREAM CANNOT FOLLOW THE UPPER CURVATURE of the AIRFOIL (because of excessive change in direction)
an > ANGLE OF ATTACK = airstream AWAY FROM TOP SURFACE OF WING (swirling/burbling)- the TURBULENT AIRFLOW at the TRAILING EDGE at lower angles of attack SPREADS FORWARD OVER ENTIRE WING (increase pressure on UPPER WINGS= LOSS OF LIFT, spreading airstream to fuselage and wings produce insufficient lift-STALL.
RECOVER FROM STALL- 1- DECREASE ANGLE OF ATTACK (angle between chord line and relative wind, not the horizon), so AIRSTREAM can FLOWBACK SMOOTHLY OVER THE WING: release back pressure or move elevator forward;
2- SMOOTHLY APPLY MAX POWER TO INCREASE SPEED and MINIMIZE LOSS OF ALTITUDE;
3- CARBURETOR HEAT OFF;
4- STRAIGHT AND LEVEL with COORDINATED PITCH/ROLL/YAW (no ailleron before angle of attack reduced)
“Washout”- wings stall progressively outward (from roots to wingtip). TIPS HAVE LESS ANGLE OF INCIDENCE (angle between chord line and longitudinal axis) THAN ROOTS.
So Roots stall first, so that the control of the aillerons (towards the tips) will still be available at high angles of attack and give the plane more stable conditions.
configuration of STALL- FLAP extension INCREASES LIFTING ability of wings, REDUCING STALL SPEED (allowing to stall at lower speed):
(lower speed) VS0- POWER OFF STALL SPEED with (gear)/FLAPS in LANDING CONFIGURATION (WHITE ARC)
(higher speed) VS1- POWER OFF STALL SPEED with FLAPS/(gear) UP (LOWER GREEN ARC)
A) LOAD FACTOR and STALL- STALL SPEED INCREASES in PROPORTION to SQUARE ROOT OF LOAD FACTOR:
ex: a plane with unaccelerated stall speed of 45knts can be stalled at 90knts if LOAD FACTOR of 4Gs.
stall induced at LEVEL FLIGHT or UNACCELERATED STRAIGHT CLIMB won’t produce additional load factors
in CONSTANT ALTITUDE TURNS- load factor causes STALL SPEED TO INCREASE AS ANGLE OF ATTACK INCREASES
B) CENTER OF GRAVITY :CG location affects:
B.1) ANGLE OF ATTACK on stall speed/ recovery
B.2) STABILITY on stall speed/ recovery
C.G. AFT- plane flies at LOWER ANGLE OF ATTACK/ critical angle of attack is exceeded at LOWER AIRSPEED (because of reduced tail down force)
but C.G. AFT= PLANE LESS STABLE because distance from elevators to C.G. is shorter (no natural tendency to pitch down: stall/flat spin recovery is harder- recovery from spin may be impossible)
FORWARD C.G.-critical angle of attack exceeded at higher speed
plane more stable- stall recovery easier (plane more tendency to pitch nose down and elevator is at greater distance from C.G.)
c) WEIGHT- (location of C.G.= STABILITY ) but regardless of STABILITY, an INCREASED WEIGHT requires:
- HIGHER ANGLE OF ATTACK for LIFT to support WEIGHT
- so, angle of attack is exceeded at higher airspeed
d) SNOW, ICE, FROST ON WINGS- accumulation on wings changes shape and disrupts smooth airflow, increasing drag, decreasing lift
e) TURBULENCE- stall at higher airspeed than in stable conditions
VERTICAL GUST/ WIND SHEAR (sudden change in relative wind) may cause ABRUPT INCREASE of ANGLE OF ATTACK (not long enough to stall but facilitates stall during the attempt to maintain the GLIDE SLOPE on landing):
IN MODERATE to SEVERE TURBULENCE /CROSSWINDS ALWAYS KEEP HIGHER THAN NORMAL APPROACH SPEED
in cruise speed keep bellow VA.
f) DISTRACTIONS
STALL RECOGNITION:
-attitude and airspeed
-less noise from engine
-kinesthesia
-feeling of control pressures resistance (less speed, less control); controls are less effective approaching critical angle of attack. and on stalls controls have pratically no effect.
- stall horn alert
SPINS: its an aggravated stall that results in auto rotation.
If nose yaws at the beggining of a stall, wing will drop in direction of yaw (unless rudder applied against the nose yaw).
The Lower Wing on a Spin has much HIGHER ANGLE OF ATTACK do the UPWARD MOTION of RELATIVE WIND against its surfaces (extreme loss of lift and >drag)
The Rising Wing becomes LESS STALLED and so develops some lift, thats WHY THE PLANE ROLLS
TO SPIN, BOTH WINGS MUST BE STALLED, ONLY THEN ONE WING BECOMES LESS STALLED THAN THE OTHER
FLAT SPIN- when SPIN AXIS LOCATED NEAR C.G.
3 PHASES:
1) `INCIPIENT’- between stall and full spin, just before balancing of aerodynamical and inertial forces
2) ‘STEADY’- spin fully developed, aerodynamic forces are in balance
3) ‘RECOVERY’- ends when level flight attained.
SPIN RECOVERY TECHNIQUE:
a) neutralize aillerons
b) close throttle (power agravates spin and causes abnormal loss in altitude during recovery)
c) apply opposite rudder – to slow rotation
d) apply positive forward elevator movement to break stall (may take some time in some planes)
e) neutralize rudder as spin stopps (otherwise excessive yaw may occur in the opposite direction)
f) return to level flight- avoid excessive elevator back pressure (because of possible 2nd stall)
SPINS PROHIBITED- to be certified for spins (NORMAL. UTILITY), an airplane must be RECOVERABLE FROM AN INCIPIENT SPIN (not a fully developed spin, i.e. beyond one turn or spiral).
If prohibition placared assume spin is irrecoverable.
_____” “________
2- AIRPLANE INSTRUMENTS, ENGINES AND SYSTEMS
PITOT STATIC SYSTEM (air pressure):
1) ALTIMETER
2) VERTICAL SPEED INDICATOR
3) AIRSPEED INDICATOR
has 2 parts:
a) PITOT PRESSURE CHAMBER and LINES (“RAM”- beneath leading edge to be seen by pilot to prevent icing and to allign with relative wind)- located to prevent minimum disturbance/turbulence (air flow)- CONNECTED ONLY TO AIRSPEED INDICATOR
b) STATIC PORT (“pressure of still air”) attached to vent side of the fuselage; including STATIC LINES that provides static air pressure to:
b.1) ALTIMETER
b.2) VSI
b.3) AI
c) sometimes therer’s a MANUAL VALVE alternative to static port (if this gets clogged) but air pressure around cockpit (just like a wing) is LOWER (acceleration of airflow), so there are different readings:
c.1) ALT may indicate HIGHER-THAN-ACTUAL
c.2) VSI may indicate CLIMB in LEVEL FLIGHT
c.3) AI may indicate HIGHER-THAN-ACTUAL
http://en.wikipedia.org/wiki/Pitot-static_system
1) THE ALTIMETER – used to calculate TRUE AIRSPEED (DENSITY ALTITUDE).
Its a MECHANICAL barometer that SHOWS ALTITUDE ACCORDING TO AIR PRESSURE (through an aneroid wafer)
LONGER POINTER- hundreds of FEET subdivided in increments of 20FEET
http://en.wikipedia.org/wiki/File:3-Pointer_Altimeter.svg
Clalibrated by ISA standards (standards for temp/pressure):
SEA LEVEL- 15 degrees C + 29.92HG
NON STANDARD PRESSURE and NON STANDARD TEMPERATURE
to COMPENSATE for NON-STANDARD PRESSURE- “KOLLSMAN WINDOW” barometric scale-works to indicate whatever height above whatever pressure level is set into the Kollsman; otherwise, when FLYING FROM A HIGHER PRESSURE AREA to a LOWER, the ALTIMETER would show LOWER THAN ACTUAL (and vice-versa)
NON-STANDARD TEMPERATURE:
warm day: expanded air=lighter in weight per unit in volume
colder day: contracted air= heavier in weight per unit in volume
THE WARMER, THE HIGHER the HEIGHTS of PRESSURE LEVEL WILL BE RAISED
Ex: the WARMER the day, the HIGHER the PRESSURE LEVEL will be
Ex: The COLDER the day, the STANDARD PRESSURE at a given ALTITUDE will be LOWER
CONCLUSION: The adjustment of the pilot for NON STANDARD PRESSURES DOES NOT COMPENSATE for NON STANDARD TEMPERATURES- “from high to low look out bellow” (to clear obstacles)
SETTING THE ALTIMETER:
1) call FSS- hourly reports atmospheric pressure corrected for sea level pressure: necessarily to ADJUST AS FLIGHT PROGRESSES (FAA: “each setting within 100NM of the aiplane“); if no FSS use the NEXT FSS STATION, if no FSS (no radio) use the DEPARTURE AIRPORT SETTING. Above 18000ft set to 29.92.
Over Mountains: warmer temperature bellow which pushes HIGHER LEVEL PRESSURE than on plains. The INDICATED ALTITUDE MAY BE 1000FT in EXCESS.
TYPES OF ALTITUDE:
a)absolute altitude (=above ground level)
b) true altitude (=ABOVE MEAN SEA LEVEL)- on airport charts, terrain or elevation altitudes are expressed in TRUE ALT.
c)indicated altitude (= TRUE ALTITUDE but without ISA values matching atmospheric conditions or same as TRUE> 18000ft)
d) PRESSURE ALTITUDE altimeter adjusted for ISA MEAN SEA LEVEL PRESSURE of 29.92 at 18.000Ft called FLIGHT LEVEL)
e) DENSITY ALTITUDE (=PRESSURE ALTITUDE adjusted for NON STANDARD TEMPERATURE VARIATIONS)
e.1) if STANDARD DENSITY and PRESSURE are THE SAME
e.2) if TEMPERATURE ABOVE STANDARD= DENSITY ALTITUDE HIGHER THAN PRESSURE ALTITUDE
e.3) if TEMPERATURE BELLOW STANDARD = DENSITY ALTITUDE LOWER THAN PRESSURE ALTITUDE
2) THE VERTICAL SPEED INDICATOR
rate of climb/descent is FT/MIN (zero at flight level if properly calibrated)
Principle of orientation- purely on Static PRESSURE but with a differential pressure system.
http://en.wikipedia.org/wiki/File:Faa_vertical_air_speed.JPG
case is airtight except for a ”calibrated leak” (passage) to the STATIC LINE of the PITOT -STATIC SYSTEM, venting the whole area surrounding the DIAPHRAGM, that also receives air from a STATIC LINE but not the “restricted passage”
When the aircraft begins to increase altitude, the diaphragm will begin to contract at a rate faster than that of the calibrated leak, causing the needle to show a positive vertical speed. The reverse of this situation is true when an aircraft is descending. The calibrated leak varies from model to model, but the average time for the diaphragm to equalize pressure is between 6 and 9 seconds. (this last paragraph in wikipedia)
3- AIRSPEED INDICATOR-
Principle of orientation- differential air pressure instrument that measures difference TOTAL PRESSURE (PITOT) and STATIC PRESSURE, called DYNAMIC PRESSURE.
http://en.wikipedia.org/wiki/File:ASI-operation-FAA.png
Its a sealed case with a diaphragm – when plane moves impact pressure becomes greater than static , causing DIAPHRAGM to EXPAND
AIRSPEED DIAL may be calibrated to convert DYNAMIC PRESSURE to KNOTS or MPH.
ASI is calibrated to display AIRSPEED representative of a given DYNAMIC PRESSURE, DOESN’T REFLECT CHANGS IN DENSITY ALTITUDE
TYPES OF AIRSPEED:
1) INDICATED AIRSPEED- uncorrected for air density variations or instrument deviations . All POH limitations/performance are IAS FAR’S and ATC
2) CALIBRATED AIRSPEED- corrected for instruments deviation
there are always ERRORS, especially at LOW AIRSPEEDS and at FLAP SETTINGS – slipstream flow from STATIC PORT causes erroneous impact or total pressure measurement and angles of attack against relative wind (from pitot)
At CRUISE/ HIGHER SPEED IAS and CAS are approximately the same
3) TRUE AIRSPEED = CAS CORRECTED FOR DENSITY ALTITUDE
AIR DENSITY decreases with altitude (so plane must be flown faster to cause same dynamic pressure/impact to be measured by ASI.
TAS= + ALT = -IAS
IAS= + ALT = + TAS
HOW TO DETERMINE TRUE AIRSPEED:
a) one method E6B- knowing CAS, outside air temperature, pressure altitude
or some AI have it built in
or by PLANNED PERFORMANCE CHART (POH) for a planned , not true airspeed
b) second method: (general rule) ADD 2% to IAS per 1000FT
(example: IAS 140, ALT 6000FT: 2%x6=12% (.12) 140x 0.12= 16.8 140x +16.8= 156.8 TAS)
TYPES OF TRUE AIRSPEED:
LOWER WHITE ARC = VS0 (stalling speed in landing config) or flaps down in max landing weight
TOP WHITE ARC= VFE (max flap extended speed)
LOWER GREEN ARC= VS1 (stalling speed at specific config) ex: power off with flaps retracted at max take off weight
TOP GREEN ARC = VN0 (max structural cruise speed)
LOWER YELLOW ARC (only smooth air) = VN0
TOP YELLOW ARC = VNE
LOWER RED ARC= VNE (never exceed speed)
OTHER AIRSPEED LIMITATIONS (not marked on ASI but placarded):
VA- DESIGN MANEUVERING SPEED (max speed at which full, abrupt deflection of controls doesn’t overstress plane)- VARIES WITH GROSS WEIGHT
VL0/ VLE- landing gear operating speeds
VX- BEST ANGLE of CLIMB (short field take off) to clear obstacle in a given distance
VY- BEST RATE OF CLIMB (gives the most altitude in given time at all times)
VGlide- Best Glide Speed (Best LIFT/DRAG max= ratio of angle of attack in power off glide that allows longest glide)
VR – rotation speed
GYROSCOPIC FLIGHT INSTRUMENTS- operated by vacuum or electrical.
-VACUUM- HEADING INDICATOR and
-ATTITUDE COORDINATOR
-ELECTRICAL- TURN COORDINATOR (only the ball)
How Vacuum works: a pump spins the rotor by suction (when a red light is on means low on vacuum. Not spinning gyros fast enough)
A GYROSCOPE is a wheel with (1) RIGIDITY in SPACE (stillness of movement) – Newton’s 1st Law of Movement and (2)PRECESSION (deflection force applied to spinning wheel)
1) TURN COORDINATOR- shows whether a plane has correct RATE of TURN for the ANGLE OF ATTACK A turn coordinator operates on precession, the same as the old ( turn indicator which senses rotation only about the vertical axis of the aircraft), but its ‘gimbal’ frame is angled upward about 30° from the longitudinal axis of the aircraft. This allows it to sense both roll and yaw. Some turn coordinator gyros are dual-powered and can be driven by either air or electricity.
the INCLINOMETER (the Ball) works by GRAVITY to indicate RATE of RUDDER needed for COORDINATED TURN. shows the relationship between the bank angle and the rate of yaw. The turn is coordinated when the ball is in the center, between the marks. The aircraft is skidding when the ball rolls toward the outside of the turn and is slipping when it moves toward the inside of the turn.
the ‘ MINIATURE PLANE` – the gimbal moves a dial on which is the rear view of a symbolic aircraft. The bezel of the instrument is marked to show wings-level flight and bank angles for a standard-rate turn.
turn coordinator does not sense pitch. This is indicated on some instruments by placing the words “NO PITCH INFORMATION” on the dial.
the ‘ 2 MINUTES` sign means that the plane at a turning rate of 3 degrees per second takes 2 minutes to make a 360.
SKID- turn too fast (TOO MUCH RUDDER) when the ball rolls toward the outside of the turn
SLIP- turn too slow (TOO LITTLE OPPOSITE RUDDER) when it moves toward the inside of the turn.
COORDINATE TURN- apply rudder pressure on the side the BALL is exposed “STOP ON THE BALL”
2) ATTITUDE INDICATOR (AI)- by vacum
GYROSCOPIC on the “horizontal plane” which is fixed to the horizon (rigidity)
has an adjustable knob (up/down) for overlapping wings with horizon bar.
Its used when horizon not in sight.
3) HEADING INDICATOR (HI) – operated by vacum
same graduation: each 5 degrees per marking= each 30 degrees of interval represented by a anumber (last zero omitted)
Giroscopic Instrument powered by Vacum (principle of rigidity in space): once plane is started COMPASS CARD MUST BE SET TO HEADING SHOWN on MAGNETIC COMPASS- the HI is not affected by forces that make magnetic compass so unprecise
PRECISION of HI:
1) because of PRECESSION (bearing friction or improper caum pressure) can cause it to CREEP or DRIFT.
2) COMPARE HI with MAGNETIC COMPASS every 15 minutes for precision (only when plane straight and level and unaccelerated flight)
3) on light planes when PITCH/BANK EXCEEDS 55 degrees, precessional forces cause instrument to SPILL (spin rapidilly)- READJUST.
4- MAGNETIC COMPASS- the only self contained direction-seeking instrument on plane- used to set and adjust HI
2 paralel metal needles pointed to N fastened to a magnetic card
COMPASS ERRORS: the magnetic force is the force of attraction of another metal – stronger at the poles (south/north MAGNETIC) or points near each end of the magnet.
A) MAGNETIC VARIATION (not technically a compass error)- needle points to MAGNETIC north and rarely to GEOGRAPHIC (like in the aeronautical charts).
Some local magnetic fields (mineral deposits) may distort Earth’s magnetic field and cause additional ERROR to the TRUE NORTH.
ISOGONIC LINES: lines of equal magnetic variations ploted in degrees of EAST and WEST VARIATION on aeronautical charts (isogonic variations are re plotted periodically on charts, because for ex the shifting of the poles)
AGONIC LINE- (ex Michigan through North Virginia) are lines correcting 2 points of ZERO VARIATION)
B) COMPASS DEVIATION- is the difference between HEADING indicated by a MAGNETIC COMPASS and a plane’s ACTUAL MAGNETIC HEADING (for each 30 DEGREES of Heading shown on a CALIBRATION CARD)
because COMPASS is not only affected by Earth’s MAGNETIC fields but also by ELECTRICAL and METAL EQUIPMENT inside the plane that slightly move needles from alignment. Depends on the HEADING, as plane turns so do electrical influences, also depends on the type of electrical equipment aboard.
To reduce compass deviation error: each compass is checked/compensated periodically and the remaining swinging errors are recorded on a compass correction card for corrected headings
C) MAGNETIC DIP- tendency of needles to point increasingly DOWNWARD (DIP) around the POLES in the and “ZEROING-IN” around the EQUATOR – IN THE NORTH HEMISPHERE (reversed in the South Hemisphere)
Most pronounced DIP error: both NORTHerly and SOUTHerly TURNING ERROR- GRAVITY on a plane TURN causes the NORTH seeking end of the compass to DIP to LOW SIDE of TURN (giving erroneous turn indication) mostly apparent on NORTH and SOUTH HEADING TURNS
a) FROM northerly heading- bank attitude- TURN TO EAST or TURN TO WEST- initial compass LAGS or indicates TURN IN THE OPPOSITE DIRECTION (decreases as approaching east or west)
b) FROM southerly heading – bank attitude- TURN TO EAST or TURN TO WEST – initial compass shows GREATER AMOUNT of TURN than actually made (decreases as approaches east or west)
c) TO northerly heading – bank attitude- FROM ANY DIRECTION- compass indication LAGS BEHIND THE TURN (ROLLOUT BEFORE desired heading is reached) “Noth Under Shoot”
d) TO southerly heading - bank attitude- FROM ANY DIRECTION -compass indication WILL LEAD AHEAD OF TURN (ROLLOUT AFTER desired heading is reached) “South Over Shoot”
D) COMPASS CARD OSCILATION- turbulence or poor control technique of fly
AIRPLANE ENGINES (engine= powerplant)
engine PROPELS the plane + furnishes ELECTRICAL, HYDRAULIC and PNEUMATIC energy + heat
-crankcase
-cilinders: 2 valves (intake and exhaust valves open and shut from carburetor or induction manifold) + 2 spak plugs
-pistons
- rods
- crankshaft
1) INTERNAL COMBUSTION (mixture of fuel +air is burnt)
2) RECIPROCATING TYPE (pressure from burning and expanding gases move the pistons in the cylinders)- ROTARY MOTION of the PISTONS: piston to rod to crankshaft to propeller
by CARBURATION (instead of fuel injection) its the manner through which FUEL is INTRODUCED INTO CYLINDER
CARBURATION is atomizing, vaporizing and mixing fuel with air in a carburetor before mixture enters cylinder (forced under pressure by the pistons)
ENGINE CYCLE:
- The intake stroke begins as the piston starts its downward travel. When this happens, the intake valve opens and the fuel/air mixture is drawn into the cylinder.
- The compression stroke begins when the intake valve closes and the piston starts moving back to the top of the cylinder. This phase of the cycle is used to obtain a much greater power output from the fuel/air mixture once it is ignited.
- The power stroke begins when the fuel/air mixture is ignited. This causes a tremendous pressure increase in the cylinder, and forces the piston downward away from the cylinder head, creating the power that turns the crankshaft.
- The exhaust stroke is used to purge the cylinder of burned gases. It begins when the exhaust valve opens and the piston starts to move toward the cylinder head once again.
there are 4 CYLINDERS (Aerostar S40)
1 CYCLE= 4 strokes of piston: 1 intake, 2 compression, 3 power, 4 exhaust = 2 revolutions of crankshaft
the 5th event is IGNITION Between COMPRESSION and POWER, when the spark plug sends spark across in cylinder and ignites mixture (then POWER stroke forces PISTON DOWN to deliver mechanical energy to CRANKSHAFT)
In order to START ENGINE the CRANKSHAFT MUST BE ALREADY ROTATED by outside power source BEFORE IGNITION: an ELECTRICAL STARTER or Manual.
IGNITION is separate from electrical system: DUAL MAGNETO which distributes electrical current to SPARK PLUG (magnet will rotate only when crankshaft is rotating- electrical starter even if MASTER SWITCH OFF, engine can fire if propeler moved from the outside)
HAND PROPING PROCEDURES (alternate to electrical starter) 1) pull propeller through counterclockwise to suck gas into the cilinders; 2) shout breaks on and magneto off; 3) one foot backwards in direction of front wheel and push plane by hub to certify breakes; 4) position propeller at 10′ o’clock (helps pull down for better engine compression); 5) shout breakes on, throttle cranked, magneto on; 6) pull down on left blade
After engine starts, starter is dis engaged (no battery any longer):
LEFT MAGNETO SPARKS SOME PLUGS
RIGHT MAGNETO SPARKS SOME OTHER PLUGS
KEY RETURNS TO ” BOTH” position where both magnetos are firing
-> THE INDUCTION SYSTEM: completes the CARBURATION by taking in the OUTSIDE AIR, mixing it with FUEL BEFORE it enters into the CYLINDERS (unlike fuel injection which is before)
1- Air Scoops
2-Ducts
3-Air Filter
4- Carburetor
1- THROTTLE- controls amount of FUEL/AIR MIXTURE (the MORE MIXTURE = MORE POWER indicated by the TACHOMETER in RPM)
2- MANIFOLD PRESSURE GAUGE- (only on turbochargers or constant speed propelers)
3- MIXTURE CONTROL- adjusts FUEL./AIR ration to compensate for varying AIR DENSITIES and airplane changes in ALTITUDE.
1 PART FUEL+ 12 PARTS AIR by weight so FUEL FLOW MUST BE VARIED TO MAINTAIN RATIO
LEAN MIXTURE= (+gas, -air)
RICH MIXTURE= (-gas, + air)
A mixture too RICH= excessive fuel consumption= loss of power= possible COOLING EFFECT= possible SPARK PLUG FAILURE
EXCESSIVE LEAN MIXTURE= possible DETONATION= possible OVER HEATING= possible engine failure and loss of power
CARBURETORS are CALIBRATED at SEA LEVEL PRESSURE for FULL RICH POSITION:
with + ALTITUDE= + WEIGHT of air (although volume of air entering carburetor remains same) it NEEDS LEANER MIXTURE.
TO READ “CARBURETOR CONTROL” - EGT (Exhaust Gas Temperatures Gauges) in centigrade degrees which varies with fuel/air ratio:
a) if TEMPERATURE HIGH (red)- enrich mixture until gauge indicates a Lower Temperature (recomended drop is between 25 and 75 degrees- engine will run smoothly again)
INDUCTION SYSTEM ICING:
CONDITION of CARBURETOR ICING: HUMIDITY (visible moisture) on freezing days or hot days
INDICATIONS of CARBURETOR ICING: either LOSS OF RPM or ROUGHNESS OF ENGINE.
Outside air enters AIR INTAKE of cowling (manifold) and through AIR FILTER to combustion chamber where mixture is ignited or, if obstructed by ICE:
(reciprocating engines icing conditions are a constant problem -induction system icing)- 3 TYPES:
1) IMPACT ICE- (-4 deg Celcius/25 deg Fah)
There’s CARBURETOR HEAT through VENTURI (which accelerates the air intake and DECREASES PRESSURE- BERNOUILLI’s PRINCIPLE, which sucks in the fuel)
2) THROTLE ICE- when iddle or partially closed throttle, it provokes water vapor condensation
(or) If THROTTLE TOO FAST forward (+gas and – air= EXCESSIVE LEAN MIXTURE) can be prevented byACCELERATOR PUMP connected to the throttle linkage by the “economizer”, which keeps the engine iddling at low rpm
3) FUEL VAPORIZATION ICE- vaporization of fuel combined with the decreasing AIR PRESSURE, sudden COOLING of MIXTURE in CARBURETOR
THE USE OF CARBURETOR HEAT:
its an ANTI-ICING device that PRE HEATS the air before it reaches the carburetor to UNFROST small accumulations and keep mixture above freezing temperature.
a) AIR FULL CARBURETOR if ICING is detected (partial heat might agravate)
plane will experience DROP IN RPM if ICING DETECTED
b) with THROTTLE IDDLE on flight ENGINE COOLS RAPIDLY (less vaporization of fuel in icing)
When landing and if suspecting icing, turn carburetor heat on before iddling and leave it on during iddling, periodically OPEN THROTTLE smoothly to help carb heat defrost.
On take off DONT USE CARB HEAT WHEN THROTTLE TO THE MAXIMUM, because carb heat decreases power and increases operat.ing temperature
CARBURETOR AIR TEMPERATURE GAUGE-
only in planes with these “CAT” may PARTIAL USAGE OF CARBURETOR HEAT be alowed:
a) yellow indicates temperatures at which icing might occur (-15/ +15 degrees) UNLESS NO MOISTURE IN THE AIR (then engine can be operated in the yellow)
b) otherwise if yellow+ moisture operate carb heat
OAT (OUTSIDE AIR TEMPERATURE GAUGES)- to calculate air temperature for TRUE AIR SPEED and detecting ICE
FUEL SYSTEM:
a) gravity fed systems (high wing planes with carburetor)
b) fuel pump systems (low wing planes)
theres a FUEL PRESSURE GAUGE
b.1) PRIMARY FUEL PUMP is engine driven (mechanical)
b.2) AUXILIARY FUEL PUMP is manually controlled and used for engine to start and emergency situations
The Fuel tanks are in the wings:
- filler openings
- fuel overflow vents (if fuel expands with high temperatures)
- sediment drain sumps
- fuel lines
-PRIMER- helps start engine in cold wheather- draws fuel from the tanks and vaporize it directly onto 1 or 2 CILINDERS- keeps engine running until enough heat is generated to vaporize
USING THE PROPER FUEL:
1) low grade or TOO LEAN MIXTURE= DETONATION (like striking piston with a hammer)
2) RED MIXTURE is 80
2.2) BLUE MIXTURE is 100L
2.3) GREEN MIXTURE is 100
2.4) CLEAR MIXTURE is jet fuel
the HIGHER the GRADE, the BIGGER the COMPRESSION WITHOUT DETONATING = more power
in shortage of the correct grade of fuel use only ALTERNATE GRADE IMMEDIATELY LOWER (automotive fuel only if recomended by manufacturer or STC (suplemental type certificate)
OIL SYSTEM:
oil gets stored in a samp inside the crankcase
4 functions:
1- LUBRICATE between surfaces over which motion occurs
2- SEAL between cylinder walls and piston (prevent combustion gases to pass over pistons)
3- CLEAN
4- COOL (engine parts during summer)- most important function.
OIL PRESSURE GAUGE- pounds of pressure per square inch (PSI)
green arc- normal; UP FROM GREEN ARC = HIGH PRESSURE (LOWER=LOW)
OIL TEMPERATURE GAUGE- indirect and delayed indication of engine rising temperature (the oil circulates through radiator to cool)
COOLING SYSTEM:
burning fuel produces heat, released by exhaust fumes. The remaining heat is eliminated by the AIR VENTS, over the FINS ON THE CYLINDERS.
over heating= LOSS OF POWER, excessive oil consumption and detonation (engine damage)
MONITOR THE INSTRUMENTS:
a) oil pressure gauge (see if oil pump operates correctly, see if oil is moving through all parts)
b) oil temperature gauge (gives indirect delayed indication of engine temperature)
c) cylinder head temperature gauge (direct and immediate engine temperature- e.g. overheat might mean need to replace coolant fluid)
TO AVOID OVER HEATING:
1-open cowling
2- increase airspeed
3- enrich mixture
4- reduce power
PROPELERS:
3 blades (AIRFOIL) on a hub that rotate transforming ROTARY POWER of engine into THRUST (one surface of blade is cambered , the other is plan)
The angle at which RELATIVE WIND hits the BLADE is the ANGLE OF ATTACK- angle causes DYNAMIC PRESSURE at the back of the propeler to be greater then atmospheric pressure on the front of the propeler (less pressure). SO, LIKE ON A WING, the reaction force goes towards lesser side of the pressure.
AERODINAMICALLY THRUST IS THE RESULT OF PROPELER SHAPE AND ANGLE OF ATTACK.
propeler is TWISTED because OUTTER PART OF THE BLADES TURN FASTER THEN ON THE INSIDE (greater travelling distance of the inside of the propeler to meet – JUST LIKE A WING HIGH.
If blade not twisted, blade tips would stall and it would produce a negative angle of attack on the hub of the propeler.
FIXED PITCH PROPELER- RPM by throttle alone
CONTROLABLE PITCH PROPELER (maneuverable by pilot):
i) two-position
ii) constant speed propeler- 2 main power controls
ELECTRICAL SYSTEM:
equipment that uses electrical:
starter motor
lighting
flaps
radio and navigation
turn coordinator gyro
fuel gauges
pitot heat (generally drains electrical systems)
ELECTRICAL SYSTEM:
a) 12 VOLT BATTERY
b) 14 VOLT DIRECT CURRENT ELECTRICAL SYSTEM
1) alternator or generator (supply energy and maintain battery ); alternator (more reliable) produces enough LOW RPM electrical current, from alternating current to direct current; its electrical output is more constant throughout ranges of engine speed but its higher in weight; generator supplies enough energy to MAINTAIN the BATTERY, the disadvantage is it may NOT PRODUCE ENOUGH current under LOW RPM, thus the battery.
alternator pic:
Generator:
2) battery- (dont connect Ground Power UNits or GPUs for starting engine if the battery is dead, it can cause overheating)
3) master switch (or battery switch)-connects all electrical systems except ignition (that one comes from the magnetos)
4) BUS BAR (terminal to connect all electrical equipment- all placared), fuses (to protect from electrical overload) and circuit breakers (these can be reset instead of replaced by pushing them in when they pop out- if they pop out a second time indicates a short circuit and should not longer be manually reset or pushed or else it can cause a fire)
5) voltage regulator (checks if current is always constant)
6) ammeter is used to measure performance of electrical system; it shows amount of energy being drawn from alternator
“center zero” (0) while electrical equipment being used means the alternator failed and current is being drawned from battery.
After START indicates GREAT POSITIVE than stabilizes to LOW POSITIVE (positive means battery charged, negative means battery discharged- ONLY WHEN STARTING- any other time its an OVERLOAD or DEFECTIVE ALTERNATOR)
most planes shut off alternator automatically when NEGATIVE AMPS. to reset alternator turn switch off and then on again
on the FEstival R40 there’s a red light instead of the ammeter that indicates discharge or generator/alternator malfunction, and green light that shows that battery is getting enough electrical charge
7) associated electrical wiring
landing gear system:
FIXED: more parasitic drag, ex: speed doubled, drag quadrupled)
2 main wheels and struts attached to fuselage or wings with self contained hydraulic (piston and cylinder filledwith oil/air- one hydraulic break on each main wheel operated independently of each other) or flexible spring shock absorbing structures.
ALWAYS TAXI WITH NO BREAKES!
stearable nose wheel connected mechanically to rudder pedals (tailwheel is stearable on tailwheel planes)
environmental system:
AIR INLET in the nose heated by engine exhaust delivers air to the cabin for cooling/heating ventilation
deice and anti-ice systems:
1) fabric reinforced rubber sheets with tubes installed on leading edge of wings, stabilizers (horizontal and vertical), activated by pilot (a pneumatic pump inflates the tubes)
2 methods of propeler ice protection:
1) electric
2) fluid (anti icing alcohol)
Otherwise most planes are placared not to fly in icing conditions.
2) FUEL ICING- because of water in tanks causing freezing screen, strainers and filters, when fuel enters carburetor, any additional cooling may freeze the water (THERFORE THE USAGE OF CARB HEAT- induction system is the basic de icing). some planes use fuel de icing additive.
3) pitot heat (otherwise static and vaccum systems could be hampered by ice)- but it severely strains the electrical system (monitor ammeter)
AIR TRAFFIC CONTROL AND AIRSPACE
A) AIRPORT PAVEMENT MARKINGS:
FAA airport pavement markings: (1-runways, 2-taxiways, 3-holding position markings, 4- other markings)
1- in WHITE
a) Runways
b) Heliports (except Hospital heliports , those are in RED)
RUNWAY MARKINGS:
3 types:
1) VISUAL
2) NON PRECISION INSTRUMENTS
3) PRECISION INSTRUMENTS
Marking Element |
Visual Runway |
Nonprecision Instrument Runway |
Precision Instrument Runway |
| Designation | X | X | X |
| Centerline | X | X | X |
| Threshold | X1 | X | X |
| Aiming Point | X2 | X | X |
| Touchdown Zone | X | ||
| Side Stripes | X | ||
| 1 On runways used, or intended to be used, by international commercial transports. 2 On runways 4,000 feet (1200 m) or longer used by jet aircraft. | |||
Runway designators: numbers/letters (L, C or R) determined by APPROACH DIRECTION. nearest one-tenth the magnetic azimuth of the centerline of the runway, measured clockwise from the magnetic north. The letters, differentiate between left (L), right (R), or center (C), parallel runways, as applicable.
Runway Aiming Point Marking- each side of the runway centerline and approximately 1,000 feet from the landing threshold.
Runway Touchdown Zone Markers – to provide distance information in 500 feet (150m) increments. These markings consist of groups of one, two, and three rectangular bars symmetrically arranged in pairs about the runway centerline. For runways having touchdown zone markings on both ends, those pairs of markings which extend to within 900 feet (270m) of the midpoint between the thresholds are eliminated
Runway Side stripe Markings- continuous white side stripes
Runway Shoulder Markings- yellow side stripes
Runway Threshold Markings- helps identify the beginning of the runway that is available for landing. In some instances the landing threshold may be relocated or displaced. Two possible configs: either 8 longitudinal stripes or number related to runway width.
Number of Runway Threshold Stripes
| Runway Width | Number of Stripes |
| 60 feet (18 m) | 4 |
| 75 feet (23 m) | 6 |
| 100 feet (30 m) | 8 |
| 150 feet (45 m) | 12 |
| 200 feet (60 m) | 16 |
Relocation of a Threshold- When a threshold is relocated, it closes not only a set portion of the approach end of a runway, but also shortens the length of the opposite direction runway. In these cases, a NOTAM should be issued by the airport operator identifying the portion of the runway that is closed, e.g., 10/28 W 900 CLSD. One common practice is to use a ten feet wide white threshold bar across the width of the runway. Although the runway lights in the area between the old threshold and new threshold will not be illuminated, the runway markings in this area may or may not be obliterated, removed, or covered
Threshold Displaced- is a threshold located at a point on the runway other than the designated beginning of the runway. Displacement of a threshold reduces the length of runway available for landings. The portion of runway behind a displaced threshold is available for takeoffs in either direction and landings from the opposite direction. A ten feet wide white threshold bar is located across the width of the runway at the displaced threshold. White arrows are located along the centerline in the area between the beginning of the runway and displaced threshold. White arrow heads are located across the width of the runway just prior to the threshold bar
runway threshold bar- A threshold bar delineates the beginning of the runway that is available for landing when the threshold has been relocated or displaced. A threshold bar is 10 feet (3m) in width and extends across the width of the runway
Demarcation Bar-A demarcation bar delineates a runway with a displaced threshold from a blast pad, stopway or taxiway that precedes the runway. A demarcation bar is 3 feet (1m) wide and yellow, since it is not located on the runway
Chevrons. These markings are used to show pavement areas aligned with the runway that are unusable for landing, takeoff, and taxiing. Chevrons are yellow
Nonprecision Instrument Runway and Visual Runway Markings
Precision Instrument Runway Markings
2- YELLOW: (taxiways, closed and hazardous areas, holding positions even if on a runway)
Taxiways- centerline, shoulders and edges, runway holding (when intersecting a runway), holding positions for ILS and MLS critical areas and taxiway taxiway intersections
centerline is continuous yellow except if its enhanced centerline to further prevent runway incursions which is paralel dashes on each side 150 ft prior to an intersection with a runway.
edge is either continuous (double) or dashed (also doubled)
shoulder
Markings for Blast Pad or Stopway or Taxiway Preceding a Displaced Threshold
Markings for Blast Pads and Stopways
a) surface painted taxiway DIRECTION SIGNS (YELLOW BACKGROUND with BLACK INSCRIPTION)- these are adjacent to centerline to the LEFT if indicating TURNS to the LEFT or to the RIGHT if indicating TURNS to the RIGHT
b) surface painted LOCATION SIGNS (BLACK BACKGROUND with YELLOW INSCRIPTION) – these are located to THE RIGHT SIDE of CENTERLINE; are used additionally to signs located alongside the taxiway
c) GEOGRAPHIC POSITION MARKINGS (for low visibility operations or visual range bellow 1200 ft); LEFT on CENTERLINE, PINK BACKGROUND with BLACK NUMBER or NUMBER/LETTER, number stands for consecutive position of marking on route, and they re 4 FT HIGH
hazardous areas,
3- (WHITE ON RED)holding positions for taxiway/taxiway or ILS/MLS critical areas (even on runways are yellow)
i) runway holding position markings (4 yellow: 2 solid, 2 dashed across runway or taxiway, the solid is where aircraft is to stop), 3 situations:
i.1) runway holding position markings on taxiways- when pilot instructed to “hold short of runway” by ATC (no clearance)
ILS
WHITE ON RED i.2) holding position markings on runways- land “hold short” operations- a sign WHITE INSCRIPTION ON RED BACKGOUND installed adajcent to markings;
The holding position markings are placed on runways prior to the intersection with another runway, or some designated point. Pilots receiving instructions “cleared to land, runway “xx”" from air traffic control are authorized to use the entire landing length of the runway and should disregard any holding position markings located on the runway. Pilots receiving and accepting instructions “cleared to land runway “xx,” hold short of runway “yy”" from air traffic control must either exit runway “xx,” or stop at the holding position prior to runway “yy.”
WHITE ON RED i.3) holding short markings for taxiways located in runways approach areas-
WHITE ON RED ii) holding position markings for ILS- A sign with an inscription in white on a red background is installed adjacent to these hold position markings. When the ILS critical area is being protected, the pilot should stop so no part of the aircraft extends beyond the holding position marking. When approaching the holding position marking, a pilot should not cross the marking without ATC clearance. ILS critical area is not clear until all parts of the aircraft have crossed the applicable holding position marking.
iii) hold position markings for taxiway / taxiway (single dashed yellow line across the taxiway) its a “hold short of the taxiway” ATC command.
iV) surface painted signs WHITE ON RED, located left to centerline prior to holding position marking
4-other markings (vehicle roadway markings, VOR checkpoint markings)
4.1- vehicle roadway markings- The vehicle roadway markings are used when necessary to define a pathway for vehicle operations on or crossing areas that are also intended for aircraft. These markings consist of a white solid line to delineate each edge of the roadway and a dashed line to separate lanes within the edges of the roadway. In lieu of the solid lines, zipper markings may be used to delineate the edges of the vehicle roadway.
4.2- VOR receiver checkpoint markings- usually at the RAMP, YELLOW BACKGROUND with BLACK INSCRIPTIONS.
The VOR receiver checkpoint marking allows the pilot to check aircraft instruments with navigational aid signals. It consists of a painted circle with an arrow in the middle; the arrow is aligned in the direction of the checkpoint azimuth
NOTE-
The associated sign contains the VOR station identification letter and course selected (published) for the check, the words “VOR check course,” and DME data (when applicable
EXAMPLE-
DCA 176-356
VOR check course
DME XXX
4.3- non movement area-boundary limits- delinetate “MOVEMENT AREA” in the YELLOW DASHED line on movemet side and YELLOW SOLID line on ‘NON MOVEMENT AREA”
4.4- marking and lighting of permanently closed runways and taxiways- lighting circuits will be disconnected. The runway threshold, runway designation, and touchdown markings are obliterated and yellow crosses are placed at each end of the runway and at 1,000 foot intervals.
4.5- temporarily closed runways and taxiways- crosses are placed on the runway only at each end of the runway. The crosses are yellow in color
A raised lighted yellow cross may be placed on each runway end in lieu of the markings
A visual indication may not be present. Pilots should check NOTAMs and the Automated Terminal Information System (ATIS).
Temp. closed taxiways usually treated as hazardous areas, in which no part of an aircraft may enter, and are blocked with barricades. However, as an alternative a yellow cross may be installed at each entrance to the taxiway
B) AIRPORT SIGNS
types of AIRPORT SIGNS:
B.1) MANDATORY INSTRUCTION SIGNS- WHITE CHARACTERS on RED BACKGROUND (to denote entrances or prohibited areas)
i) runway holding position signs
runways that intersect runways or taxiways that intersect runways:
The runway numbers on the sign are arranged to correspond to the respective runway threshold. For example, “15-33″ indicates that the threshold for Runway 15 is to the left and the threshold for Runway 33 is to the right.
taxiways that intersect the beginning of the takeoff runway, only the designation of the takeoff runway may appear on the sign
taxiway that intersects the intersection of two runways, the designations for both runways will be shown on the sign along with arrows showing the approximate alignment of each runway
in addition, the arrow indicates the direction to the threshold of the runway whose designation is immediately next to the arrow
On runways, holding position markings will be located only on the runway pavement adjacent to the sign, if the runway is normally used by air traffic control for “Land, Hold Short” operations or as a taxiway
ii) runway approach area holding position signs-to protect approach for departure:
hold an aircraft on a taxiway located in the approach or departure area for a runway so that the aircraft does not interfere with operations on that runway
the sign may protect the approach to Runway 15 and/or the departure for Runway 33:
iii) ILS critical area holding position signs
when the instrument landing system is being used, In these situations the holding position sign for these operations will have the inscription “ILS” and be located adjacent to the holding position marking on the taxiway saying “15-APCH”
iv) no entry signs
prohibits an aircraft from entering an area. Typically, this sign would be located on a taxiway intended to be used in only one direction or at the intersection of vehicle roadways with runways, taxiways or aprons where the roadway may be mistaken as a taxiway or other aircraft movement surface
B.2) LOCATION signs- YELLOW CHARACTERS on BLACK BACKGROUND
serves to IDENTIFY a taxiway/ runway or clue the pilot of an exit,
b.2.i) taxiway location sign- This sign has a black background with a yellow inscription and yellow border
The inscription is the designation of the taxiway on which the aircraft is located. These signs are installed along taxiways either by themselves or in conjunction with direction signs or runway holding position signs.
b.2.ii) runway location signs- black background with a yellow inscription and yellow border
runway on which the aircraft is located. These signs are intended to complement the information available to pilots through their magnetic compass and typically are installed where the proximity of two or more runways to one another could cause pilots to be confused as to which runway they are on.
b.2.iii) runway boundary signs- yellow background with a black inscription with a graphic depicting the pavement holding position marking
faces the runway and is visible to the pilot exiting the runway, is located adjacent to the holding position marking on the pavement. The sign is intended to provide pilots with another visual cue which they can use as a guide in deciding when they are “clear of the runway.”
b.2.iv) ILS critical area boundary signs- yellow background with a black inscription with a graphic depicting the ILS pavement holding position marking
adjacent to the ILS holding position marking on the pavement and can be seen by pilots leaving the critical area (“clear of the critical area”)
B.3) DIRECTION signs- yellow background with a black inscription. The inscription identifies the designation(s) of the intersecting taxiway(s) leading out of the intersection that a pilot would normally be expected to turn onto or hold short of. Each designation is accompanied by only one arrow indicating the direction of the turn.
When more than one taxiway designation is shown on the sign each designation and its associated arrow is separated from the other taxiway designations by either a vertical message divider or a taxiway location sign
Direction signs are normally located on the left prior to the intersection. When used on a runway to indicate an exit, the sign is located on the same side of the runway as the exit
The taxiway designations and their associated arrows on the sign are arranged clockwise starting from the first taxiway on the pilot’s left
If a location sign is located with the direction signs, it is placed so that the designations for all turns to the left will be to the left of the location sign; the designations for continuing straight ahead or for all turns to the right would be located to the right of the location sign
When the intersection is comprised of only one crossing taxiway, it is permissible to have two arrows associated with the crossing taxiway. In this case, the location sign is located to the left of the direction sign
B.4) DESTINATION signs- yellow background with a black inscription indicating a destination on the airport. These signs always have an arrow showing the direction of the taxiing route to that destination
include runways, aprons, terminals, military areas, civil aviation areas, cargo areas, international areas, and fixed base operators. An abbreviation may be used
When the inscription for two or more destinations having a common taxiing route are placed on a sign, the destinations are separated by a “dot” (D) and has one arrow
When the inscription on a sign contains two or more destinations having different taxiing routes, each destination will be accompanied by an arrow and will be separated from the other destinations on the sign with a vertical black message divider
B.5) INFORMATION signs-
Information signs have a YELLOW BACKGROUND with BLACK INSCRIPTION. They are used to provide the pilot with information on such things as areas that cannot be seen from the control tower, applicable radio frequencies, and noise abatement procedures. The airport operator determines the need, size, and location for these signs.
B.6) RUNWAY DISTANCE REMAINING signs- BLACK BACKGROUND with WHITE NUMERAL INSCRIPTIONS-may be installed along one or both side(s) of the runway. The number on the signs indicates the distance (in thousands of feet) of landing runway remaining. The last sign, i.e., the sign with the numeral “1,” will be located at least 950 feet from the runway end
(3000 feet remaining)
OTHER MARKINGS: AIRCRAFT ARRESTING SYSTEMS (EMAS)- designed to crush under the weight of commercial aircraft and they exert deceleration forces on the landing gear. These systems do not affect the normal landing and takeoff of airplanes (located mostly on overrun areas but sometimes streching over operational areas).
These markings consist of 10 feet diameter solid circles painted “identification yellow,” 30 feet on center, perpendicular to the runway centerline across the entire runway width.
a bed of lightweight, crushable concrete built at the end of a runway. The purpose of an EMAS is to stop an aircraft overrun with no human injury and minimal aircraft damage (usually none
C-AIRPORT LIGHTS
1) APPROACH LIGHT SYSTEMS- (ALS) – provide the basic means to transition from instrument flight to visual flight for landing
starts at landing THRESHOLD into APPROACH AREA:
ALS:
SFL- sequence flash lighting (meatball)
LDIN-lead in light system
a) lights extend from 2400 ft to 3000ft for a PRECISION INSTRUMENT RUNWAY
b) lights extend from 1400ft to 1500ft for NON PRECISION INSTRUMENTS RUNWAY
ALS for PRECISION INSTRUMENTS RUNWAY:
a) ALSF1 (ALS+ SFL)
b) ALSF2 (ALS+SFL)
c) SSALR (simplified short approach light system with runway alignment indicator lights)
c.1) REIL- sequence light flashing runway end identifier lights
d) MALSR- medium intensity approach light system with RAIL)
ALS for NON-PRECISION RUNWAY:
a) SSALF – simplified short approach light system with SFL
b) MALSF – medium intensity approach light system with SFL
c) ODALS- omnidirectional approach light system: 5 lights along centerline and 2 lightsboundaring threshold
2) RUNWAY LIGHTS
2.1) REIL- provide rapid and positive identification of the approach end of a particular runway. The system consists of a pair of synchronized flashing lights located laterally on each side of the runway threshold. REILs may be either omnidirectional or unidirectional facing the approach area. They are effective for:
a. Identification of a runway surrounded by a preponderance of other lighting.
b. Identification of a runway which lacks contrast with surrounding terrain.
c. Identification of a runway during reduced visibility.
2.1.1- Runway end lights – a pair of four lights on each side of the runway on precision instrument runways, these lights extend along the full width of the runway. These lights show green when viewed by approaching aircraft and red when seen from the runway
2.2) runway edge lights- to outline the edges of runways during periods of darkness or restricted visibility conditions. These light systems are classified according to the intensity or brightness they are capable:
WHITE for VFR and YELOW for IFR for the last 200ft of runway or the half of it whichever comes first to form a caution zone for landings.
The lights marking the ends of the runway emit red light toward the runway to indicate the end of runway to a departing aircraft and emit green outward from the runway end to indicate the threshold to landing aircraft
2.2.1) HIRL-High Intensity Runway Lights
2.2.2) MIRL- Medium Intensity Runway Lights
2.2.3) LIRL- Low Intensity Runway Lights (only 1 intensity setting)
2.3) in-runway lighting:
for only some PRECISION APPROACH RUNWAYS:
2.3.1) TDZL- Touchdown Zone Lighting (to indicate touchdown) 2 rows of transverse STEADY BURNING WHITE LIGHT BARS on either side of the centerline, 100ft from landing threshold up to 3000ft long or 1/2 runway whichever closer.
2.3.2) RCLS – Runway Centerline Lighting (to facilitate landing)- lights each 50ft along centerline WHITE until last 3000ft, than RED/WHITE for 2000ft and then RED last 1000ft
for both PRECISION and NON-PRECISION APPROACH RUNWAY
2.3.3) taxiway lead-off lights (exiting the runway onto taxiway)- color-coded to warn pilots and vehicle drivers that they are within the runway environment or instrument landing system/microwave landing system (ILS/MLS) critical area, whichever is more restrictive. Alternate green and yellow lights are installed, beginning with green, from the runway centerline to one centerline light position beyond the runway holding position or ILS/MLS critical area holding position.
2.3.4) taxiway lead-on lights- (entering the runway)- color-coded with the same color pattern as lead-off lights ( one side emits light for the lead-on function while the other side emits light for the lead-off function. Any fixture that emits yellow light for the lead-off function shall also emit yellow light for the lead-on function)
for LAHSO (Land and Hod Short Operations) Runways and only when LAHSO is in effect:
2.3.5) land and hold-short lights – row of 5 flashing WHITE LIGHTS at a “HOLD-SHORT” point, perpendicular to centerline
3) RWSL- Runway Status Light System (for purpose of TRAFFIC SEPARATION)- fully automated system (independent from ATC control) that provides runway status information to pilots and surface vehicle operators to indicate when it is unsafe to enter, cross, takeoff from, or land on a runway. DOES NOT SUBSTITUTE ATC CLEARANCE.
RWSL system processes information from surveillance systems and activates Runway Entrance Lights (REL), Takeoff Hold Lights (THL), and Final Approach Runway Occupancy Signal (FAROS) in accordance with the motion and velocity of the detected traffic.
REL and THL are inpavement light fixtures that are directly visible to pilots and surface vehicle operators;
FAROS activation is by means of flashing the Precision Approach Path Indicator (PAPI)
3.1) REL- Runway Entrance Lights-intended to warn pilots approaching the runway holding point area that another aircraft is in the course of either landing or departing on the same runway and currently located prior to the imminent runway intersection and detected at a speed higher than 20 knots. They consist of a line of red in-pavement lights installed longitudinally and immediately adjacent to the marked taxiway centerline. The line begins just prior to the marked Holding Point and continues to the runway edge after which one additional REL is installed near the runway centerline in line with the last two lights on the taxiway. The longitudinal spacing for the lights is such that, typically, 3 to 4 lights are positioned between the hold line and the runway edge
When activated, these RED LIGHTS indicate that there is high speed traffic on the runway or there is an aircraft on final approach within the activation area.
3.1.1)- When a DEPARTING AIRCRAFT reaches 30 knots, all taxiway intersections with REL arrays along the runway ahead of the aircraft will illuminate. As the aircraft approaches a REL equipped taxiway intersection, the lights at that intersection extinguish approximately 2 to 3 seconds before the aircraft reaches it.
3.1.2) When an aircraft on FINAL APPROACH is approximately 1 mile from the runway threshold all sets of REL light arrays along the runway will illuminate.
Lights extinguish at each equipped taxiway intersection approximately 2 to 3 seconds before the aircraft reaches it (to apply anticipated separation-ATC) until the aircraft has slowed to approximately 80 knots
3.1.3) A pilot at or approaching the hold line to a runway will observe REL illumination and extinguishing in reaction to an aircraft or vehicle operating on the runway, or an arriving aircraft operating less than 1 mile from the runway threshold.
3.1.4)a pilot observes the red lights of the REL, that pilot will stop at the hold line, or along the taxiway path and remain stopped. The pilot will then contact ATC for resolution if the clearance is in conflict with the lights
3.2- THL- Take Off Lights: in-pavement, unidirectional fixtures in a double (?) longitudinal row aligned either side (?) of the runway centerline lighting. Fixtures are focused toward the arrival end of the runway at the “position and hold” point.
extend for 1,500 feet in front of the holding aircraft (extending from the first entry point in the direct of take off until such distance after the last one that an aircraft lining up from it would be able to see a sufficient indication ahead to attract their attention)
Illuminated red lights provide a signal, to an aircraft in position for takeoff or rolling, that it is unsafe to takeoff
3.2.1) THL when DEPARTING: THLs will illuminate for an aircraft in position for departure or departing when there is another aircraft or vehicle on the runway or about to enter the runway
NOTE-
When the THLs extinguish, this is not clearance to begin a takeoff roll. All takeoff clearances will be issued by ATC
red lights of the THLs, the pilot will stop or remain stopped. The pilot will contact ATC for resolution
3.3- FAROS- activated by flashing of the Precision Approach Path Indicator (PAPI). When activated, the light fixtures of the PAPI flash or pulse to indicate to the pilot on an approach that the runway is occupied and that it may be unsafe to land.
If an aircraft or surface vehicle occupies a FAROS equipped runway, the PAPI(s) on that runway will flash or pulse
3.3.1) Whenever a pilot observes a flashing or pulsing PAPI, the pilot will verify the FAROS activation. At 500 feet above ground level (AGL), the pilot must look for and acquire the traffic on the runway. At 300 feet AGL, the pilot must contact ATC for resolution if the clearance is in conflict with the FAROS indication. If the PAPI continues to flash or pulse, the pilot must execute an immediate “go around” and contact ATC at the earliest possible opportunity.
(REL, THL, FAROS)
3.3.2)Pilot Actions at Airports with RWSL:
i) transponder ON all the way to the ramp
ii) Pilots must always inform the ATC when they have either stopped, are verifying a landing clearance, or are executing a missed approach due to RWSL or FAROS indication that are in conflict with ATC instructions. Pilots must request clarification of the taxi, takeoff, or landing clearance
ii) Never cross over illuminated red lights; immediately notify ATC of the conflict and confirm your clearance. Never land if PAPI continues to flash or pulse. Execute a go around and notify ATC.
iii) Do not proceed when lights have extinguished without an ATC clearance. RWSL verifies an ATC clearance, it does not substitute for an ATC clearance.
3.3.3) ATC Control of RWSL System:
i) Controllers can set in-pavement lights to one of five (5) brightness levels
ii) REL and THL subsystems may be independently set.
iii) Shutdown of the FAROS subsystem will not extinguish PAPI lights or impact its glide path function. Whenever the system or a component is shutdown, a NOTAM must be issued, and the Automatic Terminal Information System (ATIS) must be updated.
4) TAXIWAY LIGHTS-
edge lights (for restricted visibility)- BLUE- can be switched off or changed intensity by PILOT by keying microphone
centerlines (sometimes crossing over runways, ramps and aprons)- STEADY GREEN
clearance bar lights- 3 steady BURNING YELLOW in pavement to identify HOLDING POSITION or taxiway/taxiway crossings
 |
Clearance Bar Lights |
runway guard lights (to enhance conspicuity of taxiway/runway intersections during low visibility)
 |
Runway Guard Lights |
a) pair of elevated flashing YELLOW on either side of the taxiway
b) (or) row of in pavement YELLOW lights across the taxiway at runway holding position
c) some airports have row of 3 to 5 lights in pavement, not to be mistaken for clearance bar lights.
stop bar lights:
used to confirm ATC clearance to enter/cross active runway under low visibility
row of RED unidirectional, steady burning in pavement lights across entire taxiway at runway holding position and elevated steady-burning RED lights on each side (operated in conjunction with taxiway centerline lead-on lights from stop bar toward the runway). When ATC clears, stop lights are turned off and lead on lights turned on (automatic timer)
Dont cross even if ATC cleared to proceed to runway (if you cross and lead-on lights are extinguished contact ATC for further instructions)
 |
Stop Bar Lights |
Row of red, in-pavement lights that when illuminated designate a runway hold position. NEVER CROSS AN ILLUMINATED RED STOP BAR. |
5) CONTROL of LIGHTING SYSTEM- ATC has control of APPROACH LIGHT SYSTEMS and IN RUNWAY LIGHT SYSTEMS or FSS if airport has no ATC. PILOTS may request lights to be turned OFF and ON (including SFL- SEQUENCE FLASH LIGHTS). PILOTS may also request that intensity be changed on APPROACH, RUNWAY EDGE and IN PAVEMENT lights (including SFL).
5.1) PILOTS CONTROL of airport lighting:
some airports by keying the microphone (often available at airports with uncertain times for lighting or no ATC/FSS or part time air control service)- always at the same radio frequency (available at AFD- airport facility directory when airport FAA standard- explains types of lights, method of control and operating frequency- or IAP- instruments approach procedures, CTAF may also be used for it): REIL, VASI and runway/taxiway lights.
Suggested use is to always initially key the mike 7 times; this assures that all controlled lights are turned on to the maximum available intensity.
Due to the close proximity of airports using the same frequency, radio controlled lighting receivers may be set at a low sensitivity requiring the aircraft to be relatively close to activate the system. Consequently, even when lights are on, always key mike as directed when overflying an airport of intended landing or just prior to entering the final segment of an approach.
a full 15 minutes lighting duration is available. Approved lighting systems may be activated by keying the mike (within 5 seconds).
Radio Control System
| Key Mike | Function |
| 7 times within 5 seconds | Highest intensity available |
| 5 times within 5 seconds | Medium or lower intensity (Lower REIL or REIL-off) |
| 3 times within 5 seconds | Lowest intensity available (Lower REIL or REIL-off) |
6) AIRPORT/HELICOPTER ROTATING BEACONS
vertical light distribution to be seen above horizon;
beacon might be omnidirectional or rotating (faster flashes on rotating beacon on heliports than airports and landmarks or federal airways):
WHITE/GREEN alternating flashes- LIGHTED LAND AIRPORT
WHITE/YELLOW alternating flashes- LIGHTED WATER AIRPORT
GREEN/YELLOW/ WHITE – LIGHTED HELIPORT
2 QUICK WHITE FLASHES BETWEEN GREEN FLASHES- MILITARY AIRPORT
beacons operating daylight in CLASS B, C, D and E normally mean VISIBILTY LESS than 3 SM and 1000 FT (pilots shouldnt rely on the beacon to determine if its VFR or IFR but GET ATC clearance in accordance with 14 CFR Part 91 is required for landing, takeoff and flight in the traffic pattern )
7) OBSTRUCTIONS
WHITE/ ORANGE AVATION PAINT (daytime)for structures OVER 500FT AGL
AVIATION RED BEACONS (steady at night and flashing during the day)
or..
WHITE FLASHING LIGHTS (for reduced visibility at night)
or..
DUAL LIGHTING (flashing and steady red aviation lights+flashing high intensity lights in daylights)
or..
catenary lighting to locate high voltage transmission lines
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