Performance

Question 1

What are 4 ways fuel load can be decreased when planning a flight

Answer 1

1. Using fuel stops enroute
2. Selecting closer destination alternates
3. Using enroute alternates to reduce contingency fuel
4. Selecting more optimum routing/flight levels

Question 2

What is the obstacle accountability area, and how is adequate terrain and obstacle clearance margin determined

Answer 2

The area beyond TODA where obstacles must be considered so the net take-off path clears them by 35 ft vertically or 90 m + 0.125 × D horizontally

Adequate clearance depends on how far obstacles must be considered, based on track changes and navigation accuracy:

-Up to 300m if:
Track changes are less than 15° in VMC by day, or

Navigation accuracy is good enough in IMC or at night.

-Up to 600m if:
Track changes are more than 15° in VMC by day, or

Track changes are less than 15° but navigation accuracy is not good enough.

-Up to 900m if:
Track changes are more than 15° in IMC or at night.

Question 3

What margins must the net take-off path provide

Answer 3

Vertical clearance: 35ft

Horizontal clearance: 90 m + 0.125 × D from end of TODA

D is the distance from the end of the take-off distance available

Question 4

What do the following runway distances include:
TORA
TODA
ASDA
LDA
TORR
TODR
LDR

Answer 4

TORA: Runway only

TODA: TORA + clearway

ASDA: TORA + stopway

LDA: Runway for landing only

TORR: Run needed to lift off (vs TORA)

TODR: Run to lift off + reach screen height (vs TODA)

LDR: 50 ft to full stop (vs LDA)

Question 5

What are Net and Gross Take-Off Flight Paths

Answer 5

Gross: Actual fight path flown by test pilot corrected for ISA

Net: The reduced climb performance used for obstacle clearance, obtained by applying regulatory safety margins to the gross flight path

Question 6

What do Class A-D aircraft represent

Answer 6

A: Muilti-engine turbo-prop aircraft with max certified mass exceeding 5700kg
: All multi-engine turbine aircraft - any weight

B: Multi-engine prop driven aircraft with max certified mass of 5700kg or less

C: Multi-engine aircraft with reciprocating engines, with a max certified mass exceeding 5700kg

D: Single engine aircraft

Question 7

What are the specifications of Part 121 and Part 135 flights

Answer 7

Part 121:
-Max passenger seats of 20 or more
-Max take-off mass of greater than 8618kg or more in an all cargo configuration

Part 135:
-Max passenger seats of 19 or less
-Max take-off mass of less than 8618kg in an all cargo configuration

Question 8

What is V1
What limits and defines V1

Answer 8

V1 is the take-off decision speed

V1 is limited by:
Accelerate–stop distance available
Accelerate–go distance available
Runway length
Brake energy limits
Tyre speed limits
Minimum of VMCG
Maximum of VR

So:
V1 ≥ VMCG
V1 ≤ VR

Question 9

What is V2

What limits and defines V2

Answer 9

V2 is the take-off safety speed - minimum speed to be achieved by 35 ft, with one engine inoperative, that guarantees required climb performance. Must be at least 1.1 VMCA

V2 is limited by:
Climb gradient requirements (OEI)
Aircraft configuration
Weight
Temperature and pressure altitude

Numerically:
V2 ≥ 1.1 VMCA
V2 ≥ 1.13 Vsr - 2/3 engine turboprop
V2 ≥ 1.20 Vs - 2/3 engine turboprop
V2 ≥ 1.08 Vsr - 4 engine turboprop
V2 ≥1.15 Vs - 4 engine turboprop

Question 10

1. What is specific range
2. How is specific range calculated

Answer 10

1. Distance flown per unit of fuel
2. Groundspeed ÷ fuel flow
   Max specific range = max range speed

Question 11

1. What is maximum range
2. What is maximum endurance
3. How do jets and prop aicraft achieve max range vs max endurance

Answer 11

1. The greatest distance for a given amount of fuel
   Occurs at:
   Max L/D (jet)
   Max specific range
2. The longest time airborne for a given amount of fuel
   Occurs at:
   Minimum fuel flow
   Lower speed than max range
3. Jets:
   Max range: occurs above the minimum drag speed - L/D max
   Max endurance: occurs below minimum drag speed - L/D max
   Prop a/c:
   Max range: speed for minimum drag: at max L/D
   Max endurance: at minimum power required

Question 12

1. What determines climb gradient aftertakeoff
2. Why is climb gradient more important than rate of climb for obstacle clearance

Answer 12

1. Thrust available
   Aircraft weight
   Configuration
   Density altitude
2. Because obstacle clearance depends on height gained per unit distance, not per unit time

Question 13

What head/tail wind component is used for TORR calculations

Answer 13

Headwind: 50%
Tailwind: 150%

Question 14

What factors increase the field-length-limited take-off mass (FLLTOM)

How does V1 change with a higher or lower FLLTOM

Answer 14

Lower temperature
Lower pressure altitude
Headwind
Dry runway
Improved aircraft performance

Higher FLLTOM
More runway required, more kinetic energy, V1 increases to minimize the distance the heavier aircraft spends accelerating on a single engine after a failure

Lower FLLTOM (2 answers)
Less runway required - V1 decreases; aircraft reaches V speeds earlier, so lower V1 ensures the aircraft can still stop within the ASDA after an engine failure

A higher V1 can be selected because of the “increased” climb performance when OEI

Question 15

What is climb gradient versus climb angle

Which is numerically larger during a climb: climb gradient or climb angle

Answer 15

Climb gradient - Rate of climb relative to horizontal distance (ft/NM or %)

Climb angle - Angle between the flight path and the horizontal

Climb gradient is larger than climb angle

Question 16

Why does maximum climb angle depend on excess thrust rather than excess power

Answer 16

Climb angle(Vx) is determined by the balance of forces (Thrust - Drag), while climb rate(Vy) is determined by energy change per unit time (power)

Question 17

What is field balanced length

Answer 17

The runway length where the accelerate-stop distance equals the accelerate-go distance after an engine failure at V₁

It represents the runway length where, at V₁, either stopping or continuing the takeoff is possible within the available runway, making it the most performance-critical condition

Question 18

What do the following V-Speeds indicate:
VMCA
VMCG
VMC

Answer 18

VMCA
Lowest speed at which directional control can be maintained while airborne:
One engine inoperative: critical engine failed
Take-off power on operating engine
Bank up to 5° toward live engine allowed

VMCG
Aircraft on ground
Critical engine inoperative
Other engine(s) at take-off power
Nosewheel steering not used
Directional control by rudder only
Standard atmosphere, max take-off thrust

VMC
Generic minimum control speed
May refer to either:
VMCA (airborne), or VMCG (on the ground)

Question 19

What are Steady Load and Gust Load

Answer 19

Steady loads: Constant, predictable forces acting on a structure (e.g., 1g level flight)
-Defined by weight and speed

Gust loads: Rapid and variable forces caused by atmospheric turbulence

Question 20

Why does stall speed increase during turbulence

Answer 20

Vs ∝ √n(load factor)

In turbulence, gusts increase load factor (n)
Increased load factor increases stall speed

To generate the extra lift needed for the higher load factor, the aircraft’s angle of attack increases
Since the aircraft is closer to the critical angle, a higher airspeed is required to maintain safe flight margins

Question 21

Why does a lower tyre pressure increase the dynamic hydroplaning risk

Answer 21

It causes the tyre to deform, creating a concave shape that traps water in the center of the tread, reducing the contact pressure with the road, and limits the ability of the tread to disperse water

Question 22

1. How does an increase in aircraft weight affect V1 on a long (non-limited) runway

Answer 22

1. V1 increases

• Heavier aircraft requires a higher Vr. To minimize time spent accelerating with OEI, V1 is increased to stay closer to the higher Vr

Question 23

How does an increase in aircraft weight affect V1 when at the Field-Length-Limited Take-Off Mass (FLLTOM)

Answer 23

V1 decreases

• Ability to stop becomes a priority when field length limited. Heavier aircraft has more kinetic energy; to ensure it can stop within the remaining Accelerate-Stop Distance, the “go/no-go” decision must be made at a lower speed

Question 24

How does FLLTOM and V1 generally change when a runway becomes wet or contaminated and why

Answer 24

FLLTOM decreases
V1 decreases

• Contamination reduces braking friction and can add displacement drag (slowing acceleration)
• Lower V1 allows more runway distance for the aircraft to decelerate and stop safely if a take-off is rejected

Question 25

Why might V1 sometimes be increased on a "draggy" contaminated runway (e.g., thick slush)

Answer 25

To minimize the Accelerate-Go distance Contamination (like deep slush) creates high drag, the aircraft struggles to accelerate on one engine Higher V1 ensures more speed is gained with both engines running, making it easier to reach Vr if one engine fails Note: This is a complex trade-off and often results in a significant weight penalty to ensure the aircraft can still stop.

Question 26

For both Jet and Propeller aircraft: What is the speed for: 1. Max range 2. Max endurance

Answer 26

Jet Aircraft 1. 1.32 × Vmd 2. Vmd / L/D max Propeller Aircraft 1. Vmd / L/D max 2. Vmp (minimum power)

Question 27

At maximum endurance, what is fuel flow proportional to in jet aircraft compared to propeller aircraft

Answer 27

- Jet Aircraft Thrust Required - Propeller Aircraft Power Required

Question 28

What is the effect of a headwind on an aircrafts endurance

Answer 28

Endurance remains unchanged Range will decrease

Question 29

For both Jet and Propeller Aircraft, how is max range and max endurance found on a graph

Answer 29

Jet Aircraft - Max Range Found by drawing a tangent line from the origin (0,0) to the Thrust Required curve (Drag curve) Occurs at a higher speed than minimum drag - Max Endurance Found at the lowest point on the Thrust Required (or Drag) vs. Velocity Propeller Aircraft - Max Range Found by drawing a tangent line from the origin (0,0) to the Power Required curve Typically slightly faster than the minimum power speed - Max Endurance Found at the lowest point on the Power Required vs. Velocity

Question 30

With reference to jet aircraft, what speeds does L/Dmax correspond to

Answer 30

Minimum drag Maximum endurance Best angle of climb, Vx

Question 31

1. How does adding a clearway to a balanced runway affect the maximum V1 2. What is the primary benefit of a Clearway

Answer 31

1. V1 decreases (you can continue the takeoff at a lower speed) 2. Allows a higher takeoff weight (via lower V1)

Question 32

1. What portion of takeoff performance does a Stopway affect 2. How does adding a Stopway affect selected V1 and why

Answer 32

1. Accelerate-Stop Distance 2. V1 increases Increased ASDA gives more stopping distance after rejection

Question 33

1. What is Balanced Field Length 2. Why is balanced V1 onsidered optimal 3. What happens if V1 is increased above, or decreased below the balanced V1

Answer 33

1. A condition where ASDR = OEI TODR 2. It maximizes weight by balancing go vs stop distance 3. Above: Stop distance becomes limiting, longer runway required Below: Go distance becomes limiting, longer runway required