Draft Part 91 MOS Landing (takeoff is similar) Performance
“For subsection (2), the following must be taken into account:
(a) the landing distance available;
(b) the pressure altitude and temperature;
(c) the gradient of the runway in the direction of the landing;
(d) the wind direction, velocity and characteristics;
(e) the landing weather forecast;
(f) the obstacles in the approach path.
(4) The weight of the aeroplane at landing must not exceed the weight limitations contained in or derived from:
(i) theAFM;or
(ii) themanufacturer’sdatamanual(ifany);or
(iii) other data approved for the purpose.”
Consider a type approved to an early version of FAR 23 and still in production - the Super Decathlon. Nil info in the AFM. Manufacturers data based on the best achievement by a test pilot with no allowance for average pilot skill nor percentage allowance for conservatism. No other data is approved (the old D.O.T. P charts are not approved nor may they be valid for a newer production variant).
Manufacturers data has other issues:
- approach speed way way below 1.3 Vs, the accepted safety standard therefore unsafe
- Sealed surface only, not grass so we can’t comply with the regs at our usual airstrips
- Nil info on runway gradient so that rules out some more airfields
- Nil info on tailwinds so will have to hold if Tower notifies a tailwind
The current model certified Pitts S-2C that I fly has takeoff and landing distances in the FAA approved POH. Hard surface runway so not short, dry grass as I normally operate from. No effect of runway gradient. Nil wind only! Gee, CASA doesn't let me extrapolate beyond the approved data so can only operate from a sealed, level runway with nil wind?
A Cessna 172S that I fly occasionally also has takeoff and landing distances per an FAA approved POH and it has some useful extra info. Paved runway plus an allowance for short, dry grass. Nil wind with allowances for headwind and tailwind provided. Nil info on runway gradient however.