Quote:
Originally Posted by Fly_Unity  I have looked for my old copy of 23.149 (pre 1980) I had and couldnt find it, nevertheless Airplane flying handbook says that the the early FAR 23, AND CAR 3 didnt specify weight for VMC, and that all V-speeds are based on gross weights unless otherwise specified in the POH.
Who knows though what piper actually did though. |
You're right, we have no way to for sure. But CAR 3 went away long before 1980. My guess is that Part 23 kicked in sometime in the 60's. The section I quoted was until 1996, but I don't know if there were any other versions prior to that. I have a copy of CAR 3 at home, so I'll look just for grins, but I don't think it applies to this airplane.
Even if we could establish the laws enforce during certification, the FAA provides a lot of liberty to manufacturers in how they meet various requirements, so there are no guarantees.
Quote:
Originally Posted by Fly_Unity So your saying that they just did it because it was a common practice? |
I'm not sure what "it" you're talking about, but if you mean "light weight", yes, that's been the accepted practice for many years. Always? Well, I obviously can't say that. As you know, the further back you go, the more cavalier they were about safety.
Quote:
Originally Posted by Fly_Unity I agree that they tested it lighter, not because of performance, but because it will NOT VMC at gross weight at their altitude. The question isnt what they tested it at, but what weight, was the caculated 55 knot VMC speed based on. |
You are correct in that they do extrapolate back to sea level, and there are graphical techniques shown in the flight testing book about how they do that. I don't recall seeing any weight adjustments, though. And it doesn't make sense that they would want to do that. The V speeds that are based on max gross weight are done so to be conservative. A Vmc at max gross would not be conservative.