Tech Flashcards
What effect does stalling speed have on bank angle?
Stall speed increases by square root of load factor (Gs)
ie. 60deg load factor is 2, stall increases by 1.41x
Effect of C of G on stall speed?
Centre of pressure is usually aft of C of G, which must be opposed by tail down force from horizontal stabilizer, thus increasing effective weight, thus requiring more lift from wing, which increases stall speed.
So as C of G moves forward, more tail down force is required to counter increasing arm, which further increases stall speed.
What is the definition of load factor?
The ratio of the sum total of all aerodynamic forces acting on an aircraft to its weight.
In straight and level, load factor is 1 (gravity).
In a 60deg balanced turn centrifugal force is 1.73 which combines with gravity to give an apparent downward force of 2.
What is the definition of Mcrit (critical Mach number)?
Lowest Mach number at which airflow over any part of aircraft reaches the speed of sound.
What happens as an aircraft approaches Mcrit? What is Mach tuck?
Localized airflow can reach the speed of sound. On the wing this prevents pressure build up as it returns to the free stream around aircraft, causing a shockwave.
This massive pressure boundary causes deseparation of airflow and thus an increase in drag (called wave drag).
As aircraft flies faster, the shockwave gets stronger and moves rearwards, creating high lift further back along wing, causing aircraft to tuck/pitch nose-down.
How does wing sweep increase Mcrit?
It delays start of supersonic flow, by reducing acceleration over wing. Some airflow is parallel to chord line but sweeping causes some to flow perpendicular, known as spanwise flow.
Only the airflow parallel to chord line accelerates, so by reducing the amount of acceleration, Mcrit is increased.
What are V1 and V2?
V1- decision speed- the speed beyond which takeoff should no longer be aborted.
V2- takeoff safety speed- aircraft may be safely climbed with one engine inoperative. Must be attained at the 35ft height at the en dog the required distance.
What are Blue line and Red line speeds?
Blue- Vyse- best rate of climb with the critical engine inoperative.
Red- Vmca- minimum indicated airspeed at which the aircraft can be controlled with the critical engine inoperative.
What is a balanced field?
The ASDR is equal to TODR for aircraft weight, engine thrust, aircraft configuration and runway condition.
Why do some aircraft have winglets?
To reduce drag by preventing mixing of upper and lower airflow, thereby reducing wingtip vortices and therefore reducing induced drag. This results in lower fuel burn/increased range.
Induced drag worst at takeoff.
What is GPWS?
Ground proximity warning system.
System in aircraft to aid pilots in avoiding CFIT using radar altimeter.
Delivers warning is aircraft is in one of 7 modes eg. sink rate “ SINK RATE PULL UP”
Modern E GPWS users a terrain database to give better responses.
What is Dutch roll? How is Dutch Roll prevented?
What is induced drag? How can we reduce it?
Drag result from the d
What happens to your Mach No as you climb at a constant IAS?
Mach increases
Mach no= tas / local speed of sound
Local speed of sound decreases during climb (decreased temp) and tas increases
What is the definition of Angle Of Attack?
Angle between the line of chord and relative airflow
Draw the Lift curve for us? Why did you stop the curve there?
Draw and Stall
What is the lift formula?
Lift = 1/2 ro v^2 s
Ro is air density, v is velocity, s surface area of wing
What changes rho (air density)?
Decreases with increasing altitude. Also changes with variation in temp and humidity
How does weight effect the stalling angle?
Stall angle is constant theoretically 16deg.
Stall speed increases as as weight increases, since wing needs to fly at a higher angle of attack to generate lift for a given airspeed
How is Mach No calculated?
Mach no= tas / local speed of sound
How does temperature affect Mach?
Increased temp = increased mach number
Describe a cold front?
Forms when a cold dense air mass pushes under a warm lighter air mass, forcing it to rise. Rain/thunderstorms form as warm air mass rises, cools and condenses.
How would a warm front appear?
High clouds like cirrus, middle clouds like altostratus. Form ahead of warm front in warm air that is high above cool air.
What is TCAS, ETOPS, RVSM, EGPWS?
-Traffic collision avoidance system
-Extended twin engine operations
-Reduced vertical separation minimum
-Enhanced ground proximity warning system
What do you know about PRM?
Precision runway monitor
-High speed high precision radar used to monitor simultaneous close parallel instrument approaches
What is RNP?
Required navigation performance
-navigations specification under PBN that permit operation along precise flight path with a high level of accuracy and integrity.
What are the 4 Climb out segments and what are the gradients required for a 2 engine aircraft?
- Beginning of take to 35ft and gear fully retracted.
- 35ft/gear up to flap retraction initiated (minimum 400 agl) 2.4%
- Flaps up to climb config (flap up and final climb speed reached) 1.2%
- Climb config to 1500ft (or greater if required for obstacle clearance)
Define Final Approach fix?
Start of final approach segment
What is the Validity of the QNH on an ATIS?
15 minutes
Is the wind direction given on an ATIS true or magnetic?
Magnetic
What is the ITCZ (Inter Tropical Convergence Zone)?
Trade winds converge.
Appears as band of cloud, usually thunderstorms, that encircle globe near equator.
What is the holding speed, timing and direction when below FL140?
230 (170 if limited to cat a and b), 1 minute, distance limit specified
Flying at FL220 in a holding pattern at 300kts, what angle of bank will you use?
Rate 1 or 25 deg, whichever less aob
Too fast?
Flying at FL220 in a holding pattern at 300kts, what angle of bank will you use?
Rate 1 or 25 deg, whichever less aob
Too fast?
When the runway centre lights turn red what does that mean?
Last 2000-1000ft alternate white/red
Last 1000ft all red
What is the spacing between the runway lights?
60m for instrument runway
What is a balanced field length?
TODR = ASDR
What factors affect Vmcg, V1, Vmca? (7 items)
MTOW
Flap takeoff
Gear up
Live engine full power
Aft c of g (rudder Elsa effective)
Sea level, critical engine failed
Failed engine windmilling
Tell us about weather radar?
Radar transmitter produces a signal which is reflected by water droplets in clouds. Reflected signals are collected by receiver and processed to give the weather display to pilots. Signal beam is about 3deg wide.
Explain how a GPS works?
31 satellites emit signals that enables receivers through a combination of signals from at least 4 satellites, to calculate their location and time.
What is RAIM?
Receiver autonomous inter gritty monitoring
What is RAIM?
Receiver autonomous inter gritty monitoring
What is windshear?
A wind direction and/or speed change over a vertical or horizontal distance
Windshear warning on ATIS, what are your considerations?
Effects are turbulence, violent air movement, sudden increase or reduction in airspeed, sudden increase or decrease in ground speed and/or drift
Defence is:
-warning, recognition and avoidance
-correct response during takeoff, climb, approach and landing.
When can you descend below MDA?
Visual contact
Maintain visibility
Circling area
What is the difference between DA and MDA?
DA is a decision point while MDA is the lowest allowed altitude without visuals
When can you descend below LSALT at night?
Day requirements and
-5NM (7 for ils runway) established on centreline not below on slope papi or tvasis
-within 10NM (14 Sydney) establish not below ils glide path, and within less than full scale azimuth.
What is ADS-B what does it depend on?
Automatic dependent surveillance-broadcast
-combines aircraft’s positioning source, aircraft avionics, and ground infrastructure to create an accurate interface between aircraft and atc.
What is the climb gradient and obstacle clearance height for a missed approach?
2.5%, 100 ft
Does your aircraft have a critical engine?
Yes left (down going blade inboard)
Why is it critical?
Downgoing blade more thrust so failure of left has more yaw
What are high bypass engines?
Turbofan engines that derive most of their thrust from the fan, rather than the engine core.
Do you know what by pass ratio A320? (V2527-A5)?
4.8
What speed is Vmc (Vmca) on your aircraft? What happens if you fly below that?
86 kts
Cannot maintain directional control with critical engine failed
What is the tropopause and why do we need to know where it is?
Boundary of troposphere and stratosphere
ISA 36000ft
Poles about 20000ft, equator about 60000ft
Temperature becomes constant with increasing altitude, important factor in performance/fuel calculations. Gives indication of jet-streams/high winds/turbulence.
What rate does the temperature decrease with altitude?
ISA 2deg/1000ft