Originally Posted by aussieflyboy (Post 322622)

When I was sitting through basic systems training as a new-hire about 1 1/2 years ago, we had a discussion about this very topic, and the most senior ground instructor in the training center was brought into the class to answer some questions.
As some people have said in this thread already, most regional airlines (including us at XJT) claim to use balanced field numbers when calculating the takeoff performance data for all runways system-wide.

This is complete and utter b/s.

Somebody mentioned that their CRJ V1 and Vr numbers are often quite far apart, and i know this to be the case in larger jets like the 747. In our E-145 and E-135 aircraft, V1 and Vr are always the same.

Recently I was flying back to IAH from CRW (a 2.5 hour flight requiring nearly 10000 lbs of fuel) in a 135. It's a 6300ft runway at 1000' MSL which requires a flaps 18 takeoff (instead of the normal flaps 9).

This airport is built on top of a large hill, with sharp drop-offs on all sides including either end of this short runway.

Even with the flaps 18 takeoff, our V1 and Vr speeds were reached with much less than 2000' remaining on that runway. If this field was balanced, then I'll be a monkey's uncle...

There is NO WAY on earth that we could have even come close to stopping the airplane even at 10 knots below V1.

This is not a one off situation, either. Many times on shorter runways the end of the runway is fast approaching when the "V1, rotate" call is made leaving me thanking my lucky stars we hadn't had an engine failure or some other reason to have made a high speed abort...

Balanced... My arse...

Originally Posted by aussieflyboy (Post 322622)

In our E-145 and E-135 aircraft, V1 and Vr are always the same.

Originally Posted by Bohica (Post 322941)

Doesn't matter how long the runway is, it is still only 150' (or whatever) wide. Many botched aborts or rejected takeoffs go off the side of the runway, not the end, especially when one pilot decides to use his experience to abort past V1 while the other pilot is following procedures and trying to continue flying.

At V1 you are already flying, the wheels just happen to still be on the ground. You'd rather have the whole runway to get her stopped than whatever happens to be remaining.

Of course, if you don't think the plane will fly, then you really don't have much choice, do you?

Originally Posted by FlyerJosh (Post 322871)

Out of curiousity, what does everybody use for performance data these days?

ACA used to use Jepp data, and then switched to AeroData performance. AD was superior in my opinion since it was run about 1 hour before launch and considered many various factors. We then used the lower of the AD V1 speed or the "book" V1 which might be significantly higher. AD numbers guaranteed both balanced field and SE takeoff performance at/above V1. (IE if the engine fails at a V1 of 85 knots on a contaminated runway, at the performance weight limit you still have enough runway to accelerate on 1 engine and takeoff).

Originally Posted by ToiletDuck (Post 323003)

How's hitting V1 at 115kts and stopping harder than landing at 125kts and stopping? The only way the other guy is still trying to fly is if there's a failure of communication. Plus the guy flying is the one making that decision. His hands are on the thrust levers and his feet are on the brakes. The only way the other guy should be "trying to fly" is if he's over there making the wrong callouts. His hands shouldn't be on the controls.

Originally Posted by Bohica (Post 322941)

At V1 you are already flying, the wheels just happen to still be on the ground. You'd rather have the whole runway to get her stopped than whatever happens to be remaining.