Three problems
.... TAS, NAM calculation, 0.6% correction ....
to help, don't use figure 4.5.2 to find NAM ... use
the formula:
NAM = NGM x (TAS/GS)
So .... the
answer
CAP 697 Section4 page 32
1. TAS 431 kt temp is ISA
+12° so +12 kts TAS 443kts
2. NAM = NGM x (TAS/GS) =
3200 x (443/493) = 2875 NAM
3. Start mass = 55 000kg
... from table Range = 4151 NAM ... subtract NAM range ... 4151 - 2875 = 1276
NAM
Back to table, look for
1276 NAM ... 40 600 kg ....this is END MASS
Start mass - End mass =
55 000 - 40 600 = 14 400 kg (Fuel required)
Last correction for temp,
ISA +12, +0.7%, 14 400 x 0.7% = +100kg ....Fuel 14 500kg
NB>>>>For most examples we would advise using the formula, as Fig
4.5.2 is a nightmare