V1, Vr and V2 question

[100LL... Again!]

A compromise in structural integrity or uncontained fire in the cabin are probably the only reasons I would consider an abort after V1.

BTW:
Depending on the aircraft data, even a perfectly executed stop at one knot prior to V1 can put you off the end. Some aircarft manufacturers specify the EXACT distance from start of roll to stop - of the main gear. That can put the nose of the end by a few feet.

Oh, and the Vmu thing?

I think that guy is being a bit of a harda$$ on his FO.

Vmu can be unpublished even if it is part of the flight test program if it is not relevant for pilot operations.

Also, I'll take a pilot who can stick to SOP when the $--- hits the fan ANY day over someone who can spew data like savant, then handles a V1 cut like a frightened monkey.

If you can fly it well, not knowing the minutia is unlikely to get you in an accident. Besides, if the real thing happens, are you going to sit there and get all philosophical about FAR 25 certification requirements? And if it never happens, who cares? Fly the plane, man.

That's what I love about flying - the very instant that I learn something new, every who doesn't know it is a bloomin' idiot.

 

[SkyWestCRJPilot]

"NO matter what"? how about if both wings fell off? I can see it now...wings laying 1000' behind you on the runway, you past V1, pulling back...at least you could say "I died trying" , then again, I guess you couldn't say that.

blott, sorry I've never encountered a scenario when my wings have fallen off, nor have I ever heard of that scenario. On the CRJ you just don't have time to think about aborting after V1. Things happen too fast. After V1 you go, before V1 you stop. Today for example our V1 and VR were both the same speed at a very fast 145 knots. If I were to abort after V1 in that instance then I would also be aborting after rotating. Perhaps there may be some obscure reason to abort after V1 but I've never heard of a realistic one. For what things would YOU abort after V1? I mean would you make a list and brief that on the takeoff briefing? The risks of aborting after V1 and crashing off the end or side of the runway are far greater than taking off and dealing with the emergency airborne. For me I abort for warning messages only before V1 and after V1 it's an inflight emergency and we handle it once we're stablized in the second segment climb or later.

 

[metrodriver]

I don't know if Vmmu applies to smaller planes. On long bodied planes it is a big factor since you can achieve an angle of attack that will sustain flight at lower speeds than normal Vr, but you will be scraping the tail over the ground. You will be above the stall speed. In a short bodied aircraft your Vmmu will pretty much be your stallspeed in ground effect at max angle of attack, but you will not necessarily be scraping the tail (that might require even more rotation).
On long bodied aircraft you rotate only a few degrees nose-up, lift off and then rotate to your climb pitch angle when you're sure the tail isn't going to touch the pavement anymore.

 

[Brother Francis]

If a problem occurs after V1 which renders the airplane unairworthy, you are just screwed. The Concorde is an example of that. They were well beyond V1 when the situation went south. If they had tried to abort, it is likely the result would have been the same, just at the end of a long set of skidmarks.

It's a no brainer if an engine quits at V1-5 and you are beyond V1 by the time you react. You know it will fly with an engine out. It gets interesting when an anomaly is a little less clear cut, such as an unidentified noise, smell or vibration at V1-5.

Would you rather your stop on two flat tires begin at the last possible instant (high speed abort) or from the 1000 ft markers at the approach end of the longest runway after plenty of time to evaluate, plan and call the fire trucks? On the flip side, did the shrapnel from the disintegrating tires cripple the plane?

Is the smell from a fire in the avionics bay? Will it burn through structure, hydraulic lines or fail your flight displays before you can get around the pattern?

If you are convinced the plane will not fly, don't fly it. But high speed aborts are one of the more dangerous procedures with which you can be faced even if initiated at V1, much less above it. That is why V1 is called "Decision Speed" and that's why, as they say, they pay you the big bucks.