Those added 42% runway length are there for when things go pear-shaped.
Imagine a slightly damp runway, where there are rubber smears remaining on the first third of the RW from people braking hard (not unusual on short runways). Now you will suddenly find your braking action is all but gone. Then use full reverse and with a little crosswind, you may wander off into the grass.
Never base your numbers so that it will barely work when everything goes right. Aviation history is littered with bodies who relied on nothing going wrong.
OOR: I know what you want me to say.
I shall calculate for the worst case.
So whats the worst case? No reverser and no brakes !!!!
I donīt have a Graph for that in the books, so what?
Guess it? I think I would need about 6000 or maybe 7000 ft Runway with both US.
Shall I plan into 7000 ft Runways only ??
No, thats not what I am going to do.
I fly FAR 23 Aircraft comercial since 1992. Since 1995 as a Captain. We are opreating under JAR-OPS 1.
I donīt need somebody to tread me like a schoolboy telling me that the runway may slippery.
I told you, that I can stop without reversers within 3000 ft.
With reversers working it will be 2500 ft only.
The runway I am planning to land at, has to be 3550 ft long.
So plenty of reserve for me.
The next thing is, all the landing data is based on overflying the treashold at 50 ft.
All this small airfields are VFR. I donīt follow a GS there, wich will bring me just 50 ft over the treashold, leaving 1000 ft of good runway behind me when I touch down. Without this 50 ft, touching at the threashold, I need 1700 ft landingdistance only, with brakes and reversing.
No Rubber of hard braking pilots at the treashold, because they all overflying at 50 ft.
Pilots touching at the beginning of the runway donīt need to brake hard.
I know, that planning my aircraft with reversers and JAR-OPS 1 additionals are safe for me.
AND I KNOW I HAVE TO ADD ANOTHER 15% IF THE RUNWAY IS WET.
All I was asking here is:
Can I legaly do it, or is there any law against it.
regards
Inbalance