Hi Bob, Just wondering how to tackle the following question.

An ECHO aircraft has a basic empty weight of 1963kg and 490.75 index units

Row 1 Pilot and passenger, 77kg each
Row 2 two pax 77kg each
Row 3 two pax 77kg each
Nose 9 5kg packets
Wing comp 4 10kg packets
Rear comp 8 10kg packets

The minimum number of packets that must be removed to ensure that the centre of gravity remains within limits at all stages of flight is:

3
2
1
None

Do a load sheet to ZFW.

Total weight at ZFW = 2590
Total moment at ZFW = 699.5
Present CofG = 6995000 ÷ 2590 = 2701mm
Shift in CofG required = 2701 - 2680 = 21mm

The question asks for the minimum number of packets to be removed so you would remove them from the rear compartment.

Weight to remove = 2590 x 21 ÷ 2320 [the difference between the required CofG and the rear compartment arm]= 23kg

So you need to remove 3 x 10kg packets.

Bob,

I understand the working out you have supplied... however why can we not move one of the 10kg pack to the nose locker, rework the new moment and then remove just one of the 10kg packets from the rear locker?

or am I missing something simple here.

Hi Adrian.

Yes, according to the load data provided, 10 kgs could be added to the nose locker. There could be several reasons why this is not possible, the nose locker could be physically full with no space for another package or the packages are too large to fit in the nose locker.

The bottom line is, the examiner has asked for the number of packages to be removed from the aircraft and that is what he/she will be looking for.

Cheers W