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During flight testing, the minimum control speeds are established. The VMCG must be established with (1) _____ CG position and (2) _____ the use of nose wheel steering.
  • A
    (1) most unfavorable; (2) without
  • B
    (1) most unfavorable; (2) with
  • C
    (1) forward; (2) with
  • D
    (1) forward; (2) without

VMCG, the minimum control speed on the ground, is the calibrated airspeed during the takeoff run, at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the aeroplane using the rudder control alone (without the use of nose wheel steering) to enable the take-off to be safely continued using normal piloting skill.

The rudder control forces may not exceed 150 pounds (68.1 kg) and, until the aeroplane becomes airborne, the lateral control may only be used to the extent of keeping the wings level. In the determination of VMCG, assuming that the path of the aeroplane accelerating with all engines operating is along the centre of the runway, its path from the point at which the critical engine is made inoperative to the point at which recovery to a direction parallel to the centre line is completed may not deviate more than 30 ft (9.144 m) laterally from the centre line at any point.

As with VMCA, this must be established with:

  • maximum available take-off power or thrust on the engines.
  • the aeroplane trimmed for take-off.
  • the most unfavourable CG position.
  • maximum sea level take-off weight.
Because the aircraft rotates around the CG, the position of the CG directly affects the length of the rudder arm and, thus, the power of the rudder and fin to maintain directional stability and control. The ‘worst case’ is with the CG at the aft limit. If the requirements can be met in this configuration, the ability to maintain directional control will be enhanced at any other CG location. A more forward CG decreases VMCG.

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