[Hacker15e]

Originally Posted by germb747

Critical Engine Failure Speed (CEFS) is basically the speed at which it will take the same amount of runway to go as it would to stop (Critical Field Length). Anyone know the civilian equivalent of that speed?

In a similar thread over at APC a while back, I asked for civil equivalents of the USAF terminology I've been taught and got a couple weird responses:

http://www.airlinepilotforums.com/ai...ckrides-3.html

For example, one response was that CEFS is actually a speed to fly while airborne after losing an engine and continuing the takeoff (?).

Originally Posted by a 757 driver over at APC

the speed that you must fly if you lose the most critical engine on takeoff

So, there are definitely differences between what the USAF teaches and uses and what the civilian world teaches and uses. My experience is limited to two-engined aircraft, so there is a pretty simple set of three speeds we use for this discussion. I've always thought of them in terms of one being a max speed, one being a minimum speed, and one being an exact speed:

Originally Posted by Hacker15e in a post on APC

Decision Speed: The MINIMUM speed at which I can lose an engine, then continue the takeoff in the remaining runway distance (called MIN GO speed in the F-15E).

Refusal Speed: The MAXIMUM speed at which I can lose an engine, then STOP in the remaining runway distance (called MAX ABORT speed in the F-15E).

Critical Engine Failure Speed: THE speed at which I can lose an engine, then either takeoff OR stop in the remaining runway distance.

The strangest military/civilian difference I've seen is how I see the term "decision speed" tagged to V1 in several of the forums that are discussing this issue. Seems to me that V1 is the same as "refusal speed", but this may just be another area where terminology between the USAF and the civilian world differs. If that's the case, I can see some serious potential for negative transfer for former USAF pilots going on to fly for the airlines.