V1 Cuts and checkrides... - Page 3

Rama · 08-12-2007, 12:42 AM

Our profile (74 classic) is fly up to 800 feet level off, accelerate and clean up while the non-flying pilot and fe work the problem. Nothing is done earlier since happy hands could shut down the wrong engine and leave you with a big problem if you lose 2 on the same side at 830,00 pounds.

Hacker15e · 08-13-2007, 12:07 AM

All right, can someone help translate this into the terminology that I've been taught as a military guy? I read one civilian FO's rant on military guys going through the schoolhouse at one of the Majors, where he said "and the military guy didn't even know how to do a V1 cut!"

He was right...that's not terminology that is used in the USAF, at least. Flying multiengine airplanes is the same, regardless of the terminology, so I'm sure that it's something I've practiced before, but I just didn't recognize the name.

So, here are the terms that we use in takeoff data:

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 way I understand it, a "V1 Cut" is an engine failure that happens after max abort speed (in other words, a "go" mentality vs a high speed abort).

Thanks.

EDC757 · 08-13-2007, 12:44 AM

Quote:

Originally Posted by Hacker15e

All right, can someone help translate this into the terminology that I've been taught as a military guy? I read one civilian FO's rant on military guys going through the schoolhouse at one of the Majors, where he said "and the military guy didn't even know how to do a V1 cut!"

He was right...that's not terminology that is used in the USAF, at least. Flying multiengine airplanes is the same, regardless of the terminology, so I'm sure that it's something I've practiced before, but I just didn't recognize the name.

So, here are the terms that we use in takeoff data:

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 way I understand it, a "V1 Cut" is an engine failure that happens after max abort speed (in other words, a "go" mentality vs a high speed abort).

Thanks.

Mostly correct. But Decision Speed is a calculation that guarantees that you can stop the aircraft on the remaining runway or takeoff and reach 35 feet at the end of the runway, climb to 1500 feet and return for a landing. If the runway is short then the aircraft may be weight limited to be able to perform as such.
Critical Engine Failure Speed is the speed that you must fly if you lose the most critical engine on takeoff. Lower than this speed on a multi engine aircraft the aircraft will roll over.

EDC757 · 08-13-2007, 12:52 AM

Quote:

Originally Posted by aero550

Relax. I'm assuming ghilis meant to let it burn/run just long enough to get to some predetermined safe altitude. Last thing anyone needs is panicked, flailing hands, and heads down at 50 feet off the deck.

Be a shame to ball up the airplane trying to be a hero when it may just be an indication problem.

That's not what he said, he said that if it was producing power you let it burn and keep the power. So with something like that I would not relax.
But like I said, assuming the aircraft is under control you get the checklist out and shut it down. No panicking necessary.

OrionFE · 08-13-2007, 04:24 AM

Quote:

Originally Posted by EDC757

Mostly correct. But Decision Speed is a calculation that guarantees that you can stop the aircraft on the remaining runway or takeoff and reach 35 feet at the end of the runway, climb to 1500 feet and return for a landing. If the runway is short then the aircraft may be weight limited to be able to perform as such.
Critical Engine Failure Speed is the speed that you must fly if you lose the most critical engine on takeoff. Lower than this speed on a multi engine aircraft the aircraft will roll over.

Refusal and V1 are the same. In the navy we called "refusal" and that is when the flying pilot took his hands off the power levers. Here in the Civie world, we call V1 and the Captain removes his hands.

Decision Speed will be equal to or less than Refusal Speed. If it is more, than you are overweight for takeoff.

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