4
$\begingroup$

I was practising some mass and balance questions and I found that my answer is a little bit too far from the listed answers. Can anyone help me to see if I did something wrong?

The question was:

Given that the Dry Operating Mass (DOM) is 27 372 kg, there are 12 000 kg of trip fuel and 4 000 kg of fuel are expected on landing, what is the maximum allowable traffic load for the Medium-Range Jet Transport (MRJT) aeroplane?

  1. 23,923
  2. 23,528
  3. 19,005
  4. 19,428

My solution was:

Operating mass = DOM + Usable fuel

$27 372 - (12 000 - 4 000) = 19 372 kg$

That doesn't match any of the options, so what is the correct answer?

Improve this question
$\endgroup$
2
  • 3
    $\begingroup$ See this document, in particular the graphic on the last page. It seems you miss a parameter: ZFM or TOM. $\endgroup$
    – mins
    May 1, 2017 at 17:45
  • 1
    $\begingroup$ What is the MSTOM? $\endgroup$
    – mongo
    May 1, 2017 at 19:53

2 Answers 2

Reset to default
7
$\begingroup$

The answer is 19,428, but I could only get there by Googling 'MRJT' to get the missing information:

enter image description here

DOM + all of the fuel is 43,372.

And since MSTOM is 62,800, that leaves you with 19,428 for payload (allowable traffic load).

$$62,800 - (27,372 + 12,000 + 4,000) = 19,428$$

Below you can see the calculations for MTOM, MLM, and MZFM. Since the traffic load for the 'MTOM limited case' is the lowest, the maximum traffic load for the flight is 19,428 kg.

enter image description here
(Table courtesy of DeltaLima.)

Improve this answer
$\endgroup$
0
-3
$\begingroup$

It strikes me that your formula is correct, you just didn't follow it -- Operating Mass = DOM + usable fuel = 27 372 + (12 000 - 4 000) = 35 372

Improve this answer
$\endgroup$
1
  • 2
    $\begingroup$ Your answer is not included in the set of options. $\endgroup$
    – kevin
    May 1, 2017 at 19:34

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .