Interpolation of fuel figs
Thread Starter
Joined: Dec 2004
Posts: 115
Likes: 0
From: uk
Interpolation of fuel figs
just wondering what method people use for the "interpolation" of fuel figs in flt planning.
Eg if a ac suffers a 4% penalty for every 4000ft below it optimum, and 10% penalty at 8000ft, what would the penalty be at 5200ft below???
iv been trying to factor each one in a table eg
below by / penatly
4000 ...... 4
5000 ...... 6.5
5250 ...... 6.63
5500 ...... 6.75
6000 ...... 7
8000 ...... 10
but im not getting an accurate enough answer, is this the wrong method or just poor exicution of the correct one? any help would be appreciated.
Eg if a ac suffers a 4% penalty for every 4000ft below it optimum, and 10% penalty at 8000ft, what would the penalty be at 5200ft below???
iv been trying to factor each one in a table eg
below by / penatly
4000 ...... 4
5000 ...... 6.5
5250 ...... 6.63
5500 ...... 6.75
6000 ...... 7
8000 ...... 10
but im not getting an accurate enough answer, is this the wrong method or just poor exicution of the correct one? any help would be appreciated.
Moderator
Joined: Feb 2000
Aviation Qualifications: CPL
Posts: 14,480
Likes: 178
From: UK
If I was serious but the only thing available was a lookup table like that, I'd get some graphpaper, plot the curve, and read off that. (Or do the same in, say, Excel).
If playing safe, I'd just use the more conservative value either side.
If being lazy, I'd do an O-level standard linear interpolation, and round up!
G
If playing safe, I'd just use the more conservative value either side.
If being lazy, I'd do an O-level standard linear interpolation, and round up!
G
