Load and Trim Sheet Question

[manucordier]

Good morning,

I've been posting a question on atpforum.co.uk but I still haven't got any reply,... and since my M&B exam is on monday I cannot afford to wait much longer,... Thus I post it again here. If anyone has got time to give me a hand it will be very much appreciated. Thank you !
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Question 1 :

I was just wondering if I was doing the things right. Could you confirm my reasoning is ok ?

Have a look to the following graph:



The actual CG position at take-off is at 30%MAC.
If 30 passengers get out of the plane from cabin OC, the new CG postion will be at 27.5%MAC.

To obtain that answer I just made a translation to the left. Look in the diagram.

Is that way of doing right ? I am asking because I don't always find the exact right answer doing that.

Question 2:

I have another question, I think I lack a good and strong structure in my way of resolving the following exercise. Could someone give me some guidelines to resolve it :

(For this question use annexes 031- 11205A and 031-11205B: http://www.cours-de-math.eu/lrjt.jpg )

A turbojet aeroplane is parked with the following data:
Corrected dry operating mass: 110 100 kg
Basic corrected index: 118.6
Initial cargo distribution: cargo 1: 4 000 kg ; cargo 2: 2 000 kg ; cargo 3: 2 000 kg;
other cargo compartments are empty
Take-off mass: 200 000 kg; centre of gravity (C.G.) location: 32 %
For performance reasons, the captain decides to redistribute part of the cargo loading between cargo compartments, in order to take off with a new C.G. location of 34 %. He asks for a transfer of:

a). 1500 kg from Cargo 3 to Cargo 1
b). 1000 kg from Cargo 1 to Cargo 4
c). 1000 kg from Cargo 3 to Cargo 1
d). 500 kg from Cargo 1 to Cargo 3

Question 3:

In the following question they don't provide us with the DOI (Dry iperating Index). How can I find it ? I only Have the DOM (Dry Operating Mass).

(For this question use annex 031-12272A: http://www.cours-de-math.eu/MRJT1.jpg )

For the purpose of calculating traffic loads, an operator's loading manual gives the following standard mass values for passengers. (These values include an allowance for hand baggage)

Male 88 kg
Female 70 kg
Child 35 kg
Infant 6 kg

The standard mass value to be used for hold baggage is 14 kg per piece

The loading manifest shows the following details:

Passengers loaded

Males 40
Females 65
Children 8
Infants 5

Baggage in hold number 4: 120 pieces

Using the standard mass values given and the data in the appendix, select from the following the correct value for the mass of freight (all loaded in hold No1) which constitutes the remainder of the traffic load

a) 280 kg
b) 210 kg
c) 260 kg
d) No cargo can be loaded in Hold 1

Thank you very very much for your help,
Emmanuel.

[Keith.Williams.]

Question 1.

The shift to the left is OK but you do not appear to have reduced the total mass to account for the reduced passenger numbers.

If you do thsi does it get you closer to the correct answer?

Question 2.

To shift CG from 32% to 34% we need to move cargo aft, so only options B and D can possibly be correct.

The diagram is too small to see clearly on my computer screen.

Test 1. Go to Hold 1 in the digram and measure hove far to the left the line will move when you take out 500 kg and 1000 kg.

Test 2. Go into hold 4 and mesure haw far to the right the line will move if you put in 1000 kg (option B).

Test 3. Go into hold 3 and mesaure how far the line will move to teh right when you load 500 kg (Option D)

Add together the distances at Tests 1 and 2. Then apply the shift to the bottom of the graph. If thsi gives you 34% then option B is correct.

Add together the shifts at Tests 1 and 3. Then apply the shift at the bottom of the graph. If this gives you 34% then option D is correct.

Question 3.

Adding together all of the passengers and their bags givesa total mass of 10060 kg.

The Load Trim sheet show a total Traffic Load of 10320 kg.

Subtracting 10060 from 10320 gives 260 kg.

I hope taht all of thsi makes sense. I am a bit short of time at the moment.

[manucordier]

Keith,

I quickly read your post and it seems very clear too me. Thanks a lot.
I will have a closer look to that tonight or tomorrow.

And thanks again for sending that CD, I'll make a good use of it.

Have a good weekend.

Emmanuel.

[manucordier]

Ok Keith, thanks again, I have redone the exercises and I know now what went wrong.

Firstval, for Q1 everything is ok if I reduce the total mass to take into account for the reduced passenger numbers.

Next, for Q2 none of the proposed answer works. Thus I consider it to be an error from the question bank or from JAA.

Last, for Q3, I was misinterpreting the exercise. I got it now. Thanks.

Have a good day,
Emmanuel.

[Keith.Williams.]

Question 2.

The diagrams are too small so see clearly on my computer screen.

a). 1500 kg from Cargo 3 to Cargo 1.....Moves C of G forward, so it is incorrect.

b). 1000 kg from Cargo 1 to Cargo 4....Moves C of G aft but takes it beyond the rear limit, so it is incorrect.

c). 1000 kg from Cargo 3 to Cargo 1.....Moves C of G forward, so it is incorrect.

d). 500 kg from Cargo 1 to Cargo 3......Takes C of G aft to about 36% MAC. This is aft of the desired 34%, but is still within limits. So this is the only viable option.