Old 12-28-2008, 05:17 AM
  #85  
Sluggo_63
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Originally Posted by BoeingTanker View Post
A minor correction for you, the distance is actually 2,000 feet, and all it's based on is entering the charts with a runway available minus 2,000 ft. It has been that way in the -1-1 for many many years dating back to the A model long before the thrust reversers of the E and the new carbon brakes. Why??? Good question. My guess, only General LeMay knows for sure.

Like I said it's been that way a long time, I started in SAC in 1984 and it was there then. All it says is that if you are figuring the MINIMUM power setting for takeoff you use Runway Available (RA) - 2000 ft. You can use full runway available, it was just that now you were magically labeled a "critical takeoff" and it is recommended that you use TRT or MCL power settings. It may be one of those things that came out of a SAC reg, like 51-135 and maybe long before my time there was a limititaion on A/C's making the takeoff if it was "CRITICAL" (CFL>RA-2000). Remember in SAC safety was EVERYTHING, and the loss of a single asset was unacceptable, they would put strange restrictions like that in effect. Even today you see some strange policies placed on aircraft in AMC, but now I think it is based on lack of understanding the airframes or the infamous "the C-17 world has never done that why should the tankers?"

I do want to remind everyone that there are no absolutes in our line of work and every situation can be different. We all talk about not aborting after V1 or S1 (for those still flying military heavies). But let me quote the KC-135 flight manual:

"This manual provides the best possible operating instructions under most circumstances, but it is a poor substitute for sound judgement. Multiple emergencies, adverse weather, terrain, etc may require modification of the procedures"

and:

"In those cases where the decision to stop or go may be borderline, experience shows in general, more difficulty is experienced in attempting to stop than in attempting to continue."

and:

"Takeoff will not be aborted after S1 unless, in the opinion of the pilot, the emergency renders the airplane incapable of flight (loss of thrust exceeds the equivilent of one engine). In those cases where an abort is attempted after S1, be aware that the aircraft will probably fail to stop within the confines of the runway when S1 is at or near Refusal Speed."

With those quotes in mind I don't think you can say I would NEVER abort above V1 or S1. I will tell you that I always knew what the actual refusal speed was on each and every takeoff I made in the 135. I made my decision at S1, but in the event I experienced a severe emergency after, I would know whether I would stop on the runway of not. Did I ever use that option? No, but it was in my hip pocket in case.

And as far as second guessing crews innvolved in accidents, I'll throw this one into the mix, what if the KC-135 crew at Dyess in the 80's had decided to abort? They were well after S1 when they lost water. That aircraft was, by the takeoff data, incapable of flight. They would have departed the runway, but at a much slower airspeed. Would they have hit the ditch? would anyone have survived? I don't know, but I think this is one case where they had zero chance of flying, they were still on the ground, and I think they should have stayed there. And to answer the next question, yes I did know several people on board that plane, and their wives AND their children.

Not trying to pick a fight with anyone, this is a great discussion to have and get people thinking and talking (typing). There is no hard and fast absolute. In general, it IS better to continue after V1 , S1, but I don't think you can say never abort after V1, S1. Sometimes it is better to hit something going 60 knots instead of going 150 knots.
No one has brought up, what, in my mind is the biggest difference between S1 and V1. In the AF (at least the KC-135), S1 is the speed where you can start to make the decision to abort. It gives you several seconds of acceleration to make the decision to abort, and retard the throttles. For V1, the throttles have to be coming back by V1 to make the abort work. When I was at United, they called V1 5 knots prior to the charted V1 for that exact reason... to make the decision. I always wondered why we didn't do that at FedEx. (sorry to throw the F-word in there.)
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