Aircraft Performance

Question 1

Effects of lower pressure

Answer 1

Less power
Less thrust
Less lift

Question 2

Standard atmosphere at sea level

Answer 2

59F or 15C
29.92 “HG or 1013.2 mb
Decrease of 2C, 3.5F per 1000ft up to 35k, then constant up to 80k
Drop of 1”Hg per 1000ft

Question 3

Pressure altitude

Answer 3

Height above standard Datum Plane SDP

1. Setting barometric scale to 29.92 “HG
2. Applying a correction factor
3. Using flight computer

Question 4

Density altitude

Answer 4

Pressure altitude corrected for non standard temp

Increased density, better aircraft Performance, vice versa

Question 5

Effects of pressure on density

Answer 5

Direct proportional

Double increase double density

Question 6

Effects of altitude on density pressure

Answer 6

Decrease in temp and pressure conflicting effect

Rapid drop in pressure larger effect

Question 7

Humidity effect on density

Answer 7

Little effect
High humidity less dense, water vapor lighter than air
Decrease in overall performance

Question 8

Straight and level flight drag vs speed

Answer 8

Parasite drag predominates at high speed, induced drag at low speed
Double speed, quadruple parasite drag, 8x power to overcome draf

Question 9

Kinetic energy and potential energy

Answer 9

KE = 1/2 x m x v2
PE = m x g x h

Question 10

Angle of climb AOC

Answer 10

Max AOC performance at Vx, max altitude with minimum distance traveled, with excess thrust

Question 11

Rate of Climb ROC

Answer 11

Altitude gained over time
Max ROC performance at Vy
ROC for prop at airspeed and AOA closest to L/Dmax, for jet airspeed greater than L/Dmax and AOA less than L/Dmax
Depends on excess power, climb is work, power is rate of performing work

Question 12

Weight impact on climb performance

Answer 12

Must use higher AOA to maintain altitude, speed. Increases drag. Requires more thrust, less reserve for climb

Question 13

Service ceiling vs absolute ceiling

Answer 13

Absolute = no excess power, zero ROC
Service = unable to climb at more than 100ft/min

Question 14

Power vs wing loading

Answer 14

Power = weight (lbs) / horsepower 
Wing = weight (lbs) / sqft wing

Question 15

Endurance vs range

Answer 15

Range = distance
Endurance = time

Question 16

Specific endurance

Answer 16

Flight hours / pounds of fuel, or

1 / fuel flow

Question 17

Specific range

Answer 17

NM / pounds of fuel

Knots / fuel flow

Question 18

Cruise control

Answer 18

Condition for long range cruise

Fuel decreases, weight decreases, control optimum airspeed, altitude, power

Question 19

Max range condition

Answer 19

Speed / power is greatest

At maximum lift drag ratio L/Dmax (at particular AOA and lift coefficient, uneffected by weight, altitude)

Question 20

Region of reversed command

Answer 20

Low speed phase of flight
Below speed for max endurance
Higher power settings with decrease in air speed, high pitch
Eg short field landing

Question 21

Take off and landing performance factors

Answer 21

Function of stall speed
Rate of ac/deceleration, varies directly with imbalance of force and inversely with mass of object, 75kts 4x energy than 37 it’s, 4x distance to stop
Roll distance function of speed

Question 22

Minimum hydroplaning speed

Answer 22

Multiplying square root of main gear tire pressure in psi by 9 => knots

Question 23

Lift off speed

Answer 23

1.05 to 1.25 the stall speed

Question 24

Higher weight impact on take off

Answer 24

Higher lift off speed
Greater mass to accelerate
Increase drag, friction

Question 25

Wind effect on take off

Answer 25

10% head wind, 19% reduced takeoff distance | 10% tailwind, 21% increasr

Question 26

Effects of density altitude on takeoff

Answer 26

Greater takeoff speed Decreased thrust, less acceleration No issue for supercharged reciprocating engine until critical operating limit

Question 27

Min landing distance vs ordinary landing roll

Answer 27

Max brakes for max deceleration vs use of drag to minimize wear and tear (deceleration to 60-70% of touchdown speed)

Question 28

Effect of gross weight on landing distance

Answer 28

21% more weight = 10% more landing speed required, 20% more landing distance

Question 29

Effect of wind on landing distance

Answer 29

Same as effect of wind on takeoff acceleration

Question 30

Effect of density altitude on landing distance

Answer 30

Does not impact deceleration | Only impact due to higher TAS

Question 31

Calculate landing distance increase due to altitude

Answer 31

3.5% for each 1000ft | Eg: at 5000ft 16% greater distance

Question 32

Impact of landing speed on landing distance

Answer 32

Below specified speed, may stall Above, increase distance 10% more landing speed, 21% more distance

Question 33

TAS, IAS, CAS, EAS

Answer 33

True, indicated, calibrated, equivalent

Question 34

V s0, s1, y, x, LE, LO, FE, A, N0, NE

Answer 34

``` Power-off min speed in landing config ... in specified config Max increase in altitude per time, ROC Max altitude in horizontal distance, AOC Max speed extended landing gear Max speed to extend/retract gear Max speed with flaps Calibrated design maneuvering speed, max speed limit load can be imposed (gusts or control surface deflection) Max structural cruising speed Max speed ```

Question 35

Performance charts

Answer 35

Runway length for takeoff and landing Fuel used during flight Time to destination