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A helicopter, with its CG limits between 138 inches to 158 inches aft of the datum, should have been loaded so as to give a calculated Take-Off Mass of 24 200 kg and the CG located at 140 inches aft of the datum, with 750 kg loaded into the front cargo hold and 500 kg into the rear cargo hold. Unfortunately, the ground staff incorrectly loaded all the cargo into the forward cargo hold. If the distance between the cargo holds is 157 inches, is the helicopter's CG within limits?
  • A

    No, it is out of the rear limit.

  • B
    No, it is out of the forward limit.
  • C
    Yes, it is within limits.
  • D
    Yes, it moves rearwards, but is within limits.

It is vital that any incorrect loading, such as loading in reverse order, is picked up by a robust visual checking process. If deviation from the loading instructions exists, then the resulting effects upon aircraft weight/balance and take-off trim settings should be determined and verified before take-off.

The following formula helps to find out by how much the CG has been moved, after loading the rear cargo 500 kg into the forward cargo hold:

  • Mass Change / Total Mass = Change of CG / Distance Moved.

Solving for Change of CG we get: Change of CG = (Distance Moved x Mass Change) / Total Mass = (157 in. x 500 kg) / 24 200 kg = 3.24 in.

Since, the 500 kg baggage was loaded by mistake into the front cargo hold, instead of the rear, then the CG will move further forward and its new position will be: 140 in. - 3.24 in. = 136.76 in. aft of the datum.

The helicopter's CG limits are between 138 in. and 158 in. aft of datum. Thus, the helicopter's new CG position, 136.76 in. is out of the forward limit.

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