Hi all,

Stumbled upon this question, don't quite understand why Bob's method of choosing the limiting TOW is not used. Any help is greatly appreciated.

Given the following data, determine the maximum weight of baggage that may be carried in the rear compartment of an echo aeroplane in flight.
Weight of empty aeroplane, pilot, passengers, forward and wing compartment baggage: 2455kg
Fuel on board at takeoff: 270kg
Fuel burn to first landing: 100kg
Aeroplane is not limited by aerodrome dimensions.
Assume aeroplane can be loaded in balance.

A. 100kg
B. 155kg
C. 175kg
D. 225kg

Answer is 100kg.

Doesn't matter how you go about the solution so long as you check each and every limitation. The most limiting case is the critical limit which, in turn, gives the solution. The question is super easy as you don't have to worry about performance or CG calculations.

I suggest the easiest way to proceed is -

(a) set up a standard load calculation in whatever manner you routinely use

(b) run up the table, adding weights and checking limitations along the way

(c) the initial load of 2455 kg cuts you off at the rear hold limit of 155 kg for a ZFW of 2610 kg which is below the MZFW of 2630 kg

(c) add in the fuel gives you a TOW of 2880 kg which is OK compared to the limit of 2950 kg

(d) subtract the burn gives you a LW of 2780 kg which exceeds the MLW of 2725 kg. The rear baggage load has to reduce to fix this up so you need to remove 2780 - 2725 = 55 kg

(e) end result is a maximum rear baggage load of 155 - 55 = 100 kg.

You have checked out all the limitations so that be your final, limiting solution.

Any other way you might approach the problem will just be ayres and variations on a basic theme. I just find it easier to use the one standard calculation, fill in the bits I know, and figure out the bits I either don't know or which give me a problem. So long as you work out a protocol which suits your way of thinking and then follow it - that way you minimise the probability of getting yourself tripped up along the way.

Bob's approach is as good as any.

As you are concerned with whatever solution approach was suggested, perhaps you might post that solution and we can comment on it ?

Thanks John, your explanation makes it super easy!

The provided explanation for the question was:
2455+270kg = 2725kg
MLW = 2725kg
100kg burn off means we can take an extra 100kg of baggage to land at MLW.

Avoid that approach like the plague.

We are trying to teach people generic techniques which can be applied to whatever aircraft you find yourself flying down the track.

The solution given doesn't consider checks on

(a) hold load limit

(b) MZFW

(c) MTOW

but, rather, presumes that the MLW will be the limiting case. Works fine for this question but not a good approach at all from a training POV.

My guess is that the solution was run in the normal fashion and then, knowing the answer the quoted solution is a very terse summary of the critical bits. However you might look at it, bad training technique.