Performance

Pressure altitude corrected for non-standard temperature. Higher density altitude generally reduces takeoff and climb performance; use approved performance data for the actual conditions.

Rate is height gained per unit time; gradient is height gained per horizontal distance. A higher groundspeed requires a higher climb rate to maintain the same gradient.

A worked example teaches the calculation, but it may not represent the equipment installed in the particular aircraft being flown. Avionics changes, repairs and other modifications can alter empty weight and moment. The calculation must start from the current, aircraft-specific weight-and-balance record and then add the flight’s actual loading. Otherwise, perfectly correct arithmetic can produce a wrong final CG. Matching the aircraft identification and confirming which record is current are part of validating the inputs.

Scope: General aviation aircraft using aircraft-specific weight-and-balance records.

Sources

• FAA Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-25C, Chapter 10 — p. 10-6, Weight and Balance Restrictions; p. 10-7, note on individual records. Accessed 2026-10-03.

On landing with a strong crosswind from the right on a slippery runway, two main forces tend to push the aircraft toward the left (downwind side):
– the crosswind, which acts on the aircraft’s tail, causing the nose to yaw right
– and the reverse thrust, which acts opposite to the aircraft’s heading and reinforces the sideways force

In this scenario, the aircraft is pointing slightly to the right (into the wind), so the reverse thrust vector pushes further toward the left, combining with the crosswind to degrade directional control.

To regain control, we need to reduce the forces pushing us downwind. Since we cannot act on the wind, the best option is to:
– reduce reverse thrust to idle (not cancel it entirely)
– release the brakes to regain tire traction
– use rudder and differential braking as needed to steer back to the centerline

Once directional control is restored, reverse thrust and braking can be reapplied as appropriate.

The blue line commonly marks VYSE, the speed for the best rate of climb with one engine inoperative under the specified conditions. Above the single-engine absolute ceiling, available power is insufficient to sustain level flight even in the appropriate configuration. At that point, VYSE provides the minimum rate of sink rather than a climb. Holding the speed cannot create missing performance. The pilot must assess terrain and available performance using the aircraft’s approved engine-out data and procedures.

Scope: Piston twins using the FAA VYSE convention; check the particular AFM/POH and conditions.

Sources

• FAA Airplane Flying Handbook, FAA-H-8083-3C, Chapter 13 — p. 13-1, VYSE definition; p. 13-11, single-engine absolute ceiling and minimum sink. Accessed 2026-10-03.

A conventional light piston twin climbs using power left over after the power needed for level flight. Losing one of two engines removes roughly half the available engine power, but it can consume nearly all that excess. Additional drag and imperfect engine-out configuration further reduce the remaining margin. Consequently, climb may become very weak or impossible. The relationship is not a universal percentage: actual weight, altitude, temperature, configuration and the approved performance data determine the outcome.

Scope: Conventional wing-mounted piston twins; not a numerical rule for transport jets.

Sources

• FAA Airplane Flying Handbook, FAA-H-8083-3C, Chapter 13 — pp. 13-1 and 13-3, General and excess-thrust-horsepower example. Accessed 2026-10-03.

Total mass and center of gravity do not describe how the load is distributed over the floor. A compact crate can concentrate its weight on a small area and exceed the manufacturer’s floor-load limit even when the aircraft-wide calculation is acceptable. Compartment limits and restraint requirements also remain relevant. The load needs an approved arrangement that satisfies each applicable restriction; simply moving it to obtain a better CG does not establish that the supporting structure can carry it.

Scope: Aircraft cargo and baggage loading; exact floor and compartment limits are type-specific.

Sources

• FAA Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-25C, Chapter 10 — p. 10-5, “Floor load limit”; pp. 10-6–10-7, Weight and Balance Restrictions. Accessed 2026-10-03.

A loadsheet describes one loaded state; unloading creates different intermediate states. Removing forward cargo while substantial aft cargo remains can shift the center of gravity enough to unload the nose gear and tip the aircraft around its main gear. Airbus documents this consequence of an incorrect unloading sequence. Ground stability therefore depends on following aircraft-specific unloading instructions and required support measures, as well as calculating flight balance.

Scope: Aircraft-specific ground handling.

Sources

• Airbus Safety First — Understanding Weight and Balance (January 2015) — A variety of events, a common origin — Tail tipping. Accessed 2026-10-03.

Speedbrakes add drag, but they also reduce the wing’s lift capability. Airbus explains that their extension raises the one-g stall speed, which in turn raises the lowest selectable speed, VLS, calculated for the configuration. If the aircraft is also decelerating, its speed margin can therefore shrink from both sides: actual speed decreases while VLS rises. Deceleration is not an inevitable result of extension; the speed response also depends on thrust and flight path. This matters when managing energy at altitude. Pilots must monitor the changing speed margin and use the applicable aircraft guidance, rather than treating speedbrakes as drag that has no effect on lift.

Scope: Airbus VLS discussion and speedbrake effects in cruise; indications vary by model and flight-control law.

Sources

• Airbus Safety First — Control Your Speed in Cruise (January 2016) — Limit Speeds, VLS: Lowest Selectable speed, calculation with speedbrakes; First or Second Regime?, thrust/drag equilibrium and altitude changes for speed recovery. Accessed 2026-10-04.

Balanced V₁ is the takeoff decision speed at which the Take-Off Distance Required (TODR) equals the Accelerate-Stop Distance Required (ASDR).
At this speed, if an engine fails just before $V_{1}$, the aircraft can either:

• Stop within the ASDR, or
• Continue the takeoff and reach screen height within the TODR.

This condition defines the balanced field length, which is the minimum runway length required for a given aircraft weight.

Choosing a lower $V_{1}$ increases TODR, since the aircraft needs more distance to accelerate to $V_{2}$ with one engine inoperative.
Choosing a higher $V_{1}$ increases ASDR, as more energy must be absorbed by the brakes in case of a rejected takeoff.

In essence, balanced $V_{1}$ optimizes field-length-limited takeoff performance.

Note: The field length may be limited by:
- ASDR
- TODR
- 115% of all-engine TODR

Reminder: If an engine fails exactly at $V_{1}$, the aircraft may not be able to stop within ASDR, due to the reaction time required to recognize the failure and initiate a rejected takeoff (RTO).
That’s why $V_{1}$ is the latest point to initiate the RTO, not to complete it.

When using a balanced V₁ (i.e. when TODR = ASDR), the maximum takeoff weight (TOW) is achieved for a given field length.

On a runway without clearway or stopway, TODA = ASDA.
In such a case, for a field length limited takeoff:
- Balanced V₁ results in:
TODR = ASDR = ASDA = TODA
- Since ASDR = ASDA, V₁ cannot be increased further
- And since TODA is fixed, TOW cannot be increased either

This is because:
- Increasing TOW requires a lower V₁ (to keep ASDR ≤ ASDA)
- But lowering V₁ increases TODR, which would then exceed TODA → not allowed

However, introducing a clearway increases TODA (Take-Off Distance Available).
This allows:
- A slightly lower V₁ (to reduce ASDR)
- A slightly higher Vr (to generate the required lift at higher TOW)
- Even though TODR increases slightly with the lower V₁, the added clearway ensures TODR remains ≤ TODA

✅ Result: Higher takeoff weight becomes possible, thanks to the clearway, by using an unbalanced V₁ configuration.

In the event of an engine failure after takeoff, the flight path is divided into four distinct segments, each with specific configuration and performance requirements:

1. First segment – From screen height (35 ft) to the point where the landing gear is fully retracted.
   – Aircraft is still accelerating with gear down
   – Climb gradient must be positive for twin-engined aircraft and at least equal to 0.5% for quad-engined aircraft

2. Second segment – From gear up to acceleration altitude (no lower than 400 ft AAL).
   – Flaps remain extended
   – Aircraft must maintain $V_{2}$
   – Minimum required climb gradient is 2.4% for twin-engined aircraft and 3.0% for quad-engined aircraft.

3. Third segment – From acceleration altitude to the point where the flaps and slats are fully retracted.
   – The aircraft accelerates from $V_{2}$ toward final segment speed
   – Configuration transitions to clean

4. Fourth segment – From flaps retracted to 1500 ft AAL or the applicable minimum safe altitude (MSA).
   – Climb continues at a higher speed with reduced thrust
   – Minimum required climb gradient is 1.4% for twin-engined aircraft and 1.7% for quad-engined aircraft

Takeoff performance assumes a defined rotation technique, including the rate at which pitch increases. A slower rotation keeps the aircraft on or close to the runway for longer, using distance before the required flight path is established. Airbus documented an event with normal acceleration but poor takeoff performance caused by slow rotation. Starting at VR is therefore only part of achieving the calculated result. Crews should use the rotation rate and technique specified for their aircraft, not an improvised gentler rate.

Scope: Airbus takeoff-performance assumptions; requested rotation rate varies by model, including the A220.

Sources

• Airbus Safety First — A Focus on the Takeoff Rotation (January 2021) — Case Study: A340 Long Takeoff; “The requested takeoff rotation rate value”. Accessed 2026-10-03.