Maneuvering speed

A flight envelope diagram showing VS (Stall speed at 1G), VC (Corner/Maneuvering speed) and VD (Dive speed)

In aviation, the maneuvering speed of an aircraft is an airspeed limitation selected by the designer of the aircraft. At speeds close to, and faster than, the maneuvering speed, full deflection of any flight control surface should not be attempted because of the risk of damage to the aircraft structure.[1]

The maneuvering speed of an aircraft is shown on a cockpit placard and in the aircraft's flight manual but is not commonly shown on the aircraft's airspeed indicator.

In the context of air combat manoeuvring (ACM), the maneuvering speed is also known as corner speed or cornering speed.[2]

Implications

It has been widely misunderstood that flight below maneuvering speed will provide total protection from structural failure. In response to the destruction of American Airlines Flight 587, a CFR Final Rule was issued clarifying that "flying at or below the design maneuvering speed does not allow a pilot to make multiple large control inputs in one airplane axis or single full control inputs in more than one airplane axis at a time". Such actions "may result in structural failures at any speed, including below the maneuvering speed."[3]

Design maneuvering speed VA

VA is the design maneuvering speed and is a calibrated airspeed. Maneuvering speed cannot be slower than V_s \sqrt{n} and need not be greater than Vc.[4]

Maximum operating maneuvering speed VO

Some aircraft have a maximum operating maneuvering speed VO. The concept of maximum operating maneuvering speed was introduced to the USA type-certification standards for light aircraft in 1993.[1][5] The maximum operating maneuvering speed is selected by the aircraft designer and cannot be faster than V_s \sqrt{n}, where Vs is the stalling speed of the aircraft, and n is the maximal allowed positive load factor.

At airspeeds slower than V_s \sqrt{n} the aircraft will stall before the structure is subjected to its limiting aerodynamic load. The maneuvering speed or maximum operating maneuvering speed depicted on a cockpit placard is calculated for the maximum weight of the aircraft. Some Pilot's Operating Handbooks also present safe speeds for weights less than the maximum.

The formula used to calculate a safe speed for a lower weight is \scriptstyle V_A \sqrt{W_2 \over W_1}, where VA is maneuvering speed (at maximum weight), W2 is actual weight, W1 is maximum weight.[6]

See also

References

  1. ↑ 1.0 1.1 Federal Aviation Administration, Advisory Circular 23-19A, Airframe Guide for Certification of Part 23 Airplanes, Section 48 (p.27) Retrieved 2012-01-06
  2. ↑ CNATRA P-821 (Rev. 01-08) "Flight Training Instruction, Advanced Naval Flight Officer (T-45C)". Department of the Navy, 2008.
  3. ↑ Federal Aviation Administration, 14CFR §25.1583 Final Rule Retrieved 2012-01-06
  4. ↑ 14 CFR §23.335(c)(2) Definition of Maneuvering Speed
  5. ↑ USA 14CFR §23.1557 Retrieved 2012-01-06
  6. ↑ Jeppesen Instrument/Commercial Manual. 2000. ISBN 0-88487-274-2.

External links