Originally Posted by
QuebecLima
Good morning / ... all,
in preparation for an interview I'm reviewing my atpl stuff amongst which are altimetry and M&B.
If possible, can someone confirm whether my thinking is correct:
1) Altimetry
Flying at FL 130
grid MORA 12.600 ft
QNH950 hPA
ISA conditions
Will we clear the obstacles?
I would say yes based on following calculation:
hPa correction: 1013 hPa - 950 hPa = 63 hPa = 1.890 ft;
FL130 = 13.000 ft
--> Pressure height = 13.000 ft + 1890 ft = 14.890 ft
My confusion: it mentions flying at FL 130 so do I then assume we have standard on the altimeter, clearing the MORA by 400 ft?
In addition, a small confirmation request:
let's say it's ISA + 4, which is warmer so higher, I'd have to add 480 ft (120 ft/ ° isa deviation), right?
2) M&B calculation
Given weights:
DOM
fuel (general fuel, so simple calculation (not taxi, trip,..)
MTOM
MLM
MZFW
What is the max payload?
my calculation
A] Get the lowest of MLM, MTOM and MZFW
B] Calculate Operating mass by adding DOM + FUEL
C] Subtract Operating mass from the lowest in A
Would this be correct?
Thanks
When flying on STD (1013) so in Flight Levels remember that:
- If local QNH is
low (so lower than your 1013) -> look out
below!
- if local QNH is
high (higher than your 1013) ->
look happy the sky!
The rest is math.