Mass and Balance Help
Thread Starter
Joined: Jan 2023
Posts: 13
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From: County Durham
Mass and Balance Help
Folks,
I'm reaching out for a bit of support, after banging my head for a while. I'm currently studying for my CPL exams for FI (PPLA) through the exempted route (no formal ground school) and am stumped as to why I cannot get the right answer on one of the Oxford Mass and Balance example questions.
The question is the Example Question on Page 77 of the Mass and Balance Performance book and goes;
A scheduled flight of three hours estimated time, within Europe, is to be conducted. Using the data given and the information in the CAP 696 MRJT1, calculate the maximum mass of freight that may be loaded in the following circumstances:
Performance limited take-off mass 67900 kg
Performance limited landing mass 56200 kg
MZFM 51300 kg
DOM 34960 kg
Fuel on board at ramp 15800 kg
Taxi fuel 450 kg
Trip fuel 10200 kg
Passengers (adults/each 84 kg) 115
(Children/each 35 kg) 6
Flight crew (each 85 kg) 2
Cabin crew (each 75 kg) 5
Allow standard baggage for each passenger (13 kg)
By both the calculation method and Load & Trim Sheet I cant seem to get the correct answer of 1047kg.
The closest I can get is 1137kg and that is with a traffic load of 11353kg (accounting for crew being included in DOM and that the MSTOM in CAP696 is 62800kg (with the performance limited one a rouse as its higher than the structural max).
Pulling my hair out so any guidance would be gratefully received.
I'm reaching out for a bit of support, after banging my head for a while. I'm currently studying for my CPL exams for FI (PPLA) through the exempted route (no formal ground school) and am stumped as to why I cannot get the right answer on one of the Oxford Mass and Balance example questions.
The question is the Example Question on Page 77 of the Mass and Balance Performance book and goes;
A scheduled flight of three hours estimated time, within Europe, is to be conducted. Using the data given and the information in the CAP 696 MRJT1, calculate the maximum mass of freight that may be loaded in the following circumstances:
Performance limited take-off mass 67900 kg
Performance limited landing mass 56200 kg
MZFM 51300 kg
DOM 34960 kg
Fuel on board at ramp 15800 kg
Taxi fuel 450 kg
Trip fuel 10200 kg
Passengers (adults/each 84 kg) 115
(Children/each 35 kg) 6
Flight crew (each 85 kg) 2
Cabin crew (each 75 kg) 5
Allow standard baggage for each passenger (13 kg)
By both the calculation method and Load & Trim Sheet I cant seem to get the correct answer of 1047kg.
The closest I can get is 1137kg and that is with a traffic load of 11353kg (accounting for crew being included in DOM and that the MSTOM in CAP696 is 62800kg (with the performance limited one a rouse as its higher than the structural max).
Pulling my hair out so any guidance would be gratefully received.
Last edited by ChecksD; 7th September 2024 at 12:38.
Joined: Feb 2002
Posts: 324
Likes: 0
From: Sunny Solihull
You can get 1047 by :-
115 A x84 = 9660
6 C x35 = 210
121 bags x 13 = 1573
Traffic Load = 11443
Then 62800 - (DOM 34960 + TL 11443 + T/O Fuel 15350) = 1047 kg (which I believe is incorrect - see below)
You should of course check all 4 potential limits, which unless I am going crazy you are actually limited by Max Structural Taxi/Ramp Mass of
63060 - (34960+11443+ Ramp Fuel 15800) = 857 kg
115 A x84 = 9660
6 C x35 = 210
121 bags x 13 = 1573
Traffic Load = 11443
Then 62800 - (DOM 34960 + TL 11443 + T/O Fuel 15350) = 1047 kg (which I believe is incorrect - see below)
You should of course check all 4 potential limits, which unless I am going crazy you are actually limited by Max Structural Taxi/Ramp Mass of
63060 - (34960+11443+ Ramp Fuel 15800) = 857 kg
Last edited by RichardH; 7th September 2024 at 18:42. Reason: Minor correction
Thread Starter
Joined: Jan 2023
Posts: 13
Likes: 0
From: County Durham
Thanks so much...
you know when you've been staring at something for so long..
. Seems my errors were;
Calculating - used the performance limited landing mass in the calculations which meant I selected landing mass as the limiting figure, not the ZFM.
In the sheet - a simple transposition of 9870 versus 9780 in the PAX load was mucking the job up.
As an aside, I concur on the ramp limitation. Max Taxi Mass - 63,060kg which with a taxi AUW of 62,203, is 857KG
you know when you've been staring at something for so long... Seems my errors were;Calculating - used the performance limited landing mass in the calculations which meant I selected landing mass as the limiting figure, not the ZFM.
In the sheet - a simple transposition of 9870 versus 9780 in the PAX load was mucking the job up.
As an aside, I concur on the ramp limitation. Max Taxi Mass - 63,060kg which with a taxi AUW of 62,203, is 857KG
