engine falilure after V1 before VR and a long runway?

[atr42flyer]

what would you do?

I would think that you would continue with how you pre-briefed the departure with the other crewmember. I also remember somthing about a max V1 which is usually higher than both v1 and vr. i know there are lots of people smarter than me so what would you do? lets just say your in a regional jet of some sort.

 

[KeroseneSnorter]

what would you do?

I would think that you would continue with how you pre-briefed the departure with the other crewmember. I also remember somthing about a max V1 which is usually higher than both v1 and vr. i know there are lots of people smarter than me so what would you do? lets just say your in a regional jet of some sort.

V1 is defined as takeoff decision speed......so I am not sure what your question is. Anything after V1 and you are going, period.

Maybe the only other issue would be massive structural damage from a catastrophic engine failure that makes the airplane unflyable or something, Maybe a deer strike or something else like that will put the ability to fly into question, in that case maybe sliding off the end is better than trying to go in when flight ability is in doubt.

There are few runways long enough to get a transport catagory jet stopped before running off the end if you are past V1 speed.

EDIT: I see what you are asking now....but unless you specifically calculated the absolute maximum V1 for the takeoff, you have no idea if you have enough runway or brake energy left to get stopped, so you go with what you know, after v1, you go. Simple engine failure it is never a queston, post v1 you go.

 

[fogrunner]

V1 is defined as takeoff decision speed

Not anymore.. The definition was changed in 1994 by the FAA


V1 means the maximum speed in the takeoff at which the pilot must take the first action (e.g., apply brakes, reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance. V1 also means the minimum speed in the takeoff, following a failure of the critical engine at VEF, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance.

At Gemini we call V1 5 knots early. Our training is basically once we hear V1 we are committed to the t/o. Even at our max weight, with reduced power settings we can safely meet all climb requirements.
Why compound your problems with an abort after V1 IE very hot brakes, brake fire, blown tires, now you have controllabilty problems.

 

[81Horse]

At Gemini we call V1 5 knots early. ... Why compound your problems with an abort after V1 IE very hot brakes, brake fire, blown tires, now you have controllabilty problems.

Oh, man -- I'm with you. I don't like waiting until it's very V1.

 

[CA1900]

...unless you specifically calculated the absolute maximum V1 for the takeoff, you have no idea if you have enough runway or brake energy left to get stopped, so you go with what you know, after v1, you go.

Yup. Here's an extreme example of what happens

Mesa 5326 Report (Cached version, as the NTSB database is down right now. If that link fails, here's the live link whenever it's back online.)


In short, the airplane got airborne, and the frozen-up stall horn started going off. 20 feet in the air and climbing, the captain said, "Abort! Abort!" It wasn't a simple engine failure as we were discussing, but the criteria are the same: You're above V1 and the airplane's flying, you continue. You have no idea if you have enough runway left to stop. (And in the case of this accident, they didn't.)

 

[User546]

Interesting report.

Can someone explain this phrase:

"The sound of the horn ceased, at 0922:28, and the captain called out, "abort Doris Doris," at 0922:29. The CVR recorded the sounds of impact and the recording ended, at 0922:31."

 

[avbug]

If you're above V1, you're going, period. That you have more runway in front of you means you have an obstacle free clearway...that's good...but it's not there for stopping.

High speed aborts are dangerous. Period. Ever wonder why the FAA limits abort demos on practical tests to 40% of your refusal speed? The FAA knows, based on history and statistics, that a high speed abort stands a fairly high probability of ending badly, and there's no reason for it.

If I have a long runway, I may leave well enough alone and use the calcualted V speeds. If it's a shorter runway, I may include a primary refusal speed; any malfunction prior to that speed, I'll abort. Above that, I'm only aborting for critical items, such as engine fire, engine failure, or loss of directional control. My decision, made before ever entering the runway environment, may also be tempered by surrounding terrain, runway gradient, runway surface condition (eg, contaminated runway), and so forth. NBAA and other safety organizations have suggested 80 knots as an all encompassing refusal speed (or decision speed, if you will), where one will abort for any light or indicated malfunction.

You should have briefed the contingencies. If you're past V1 and encounter a problem, you're way, way beyond the time to be reconsidering or second guessing your preflight planning and briefing.

By the time you hear V1, you're right on top of or passing through Vr and well on your way to V2 in many cases. In most aircraft, that transition period doesn't last long, and trying to split knots or one second from the next is thinking too much...it can get you hurt.

A more interesting possibility that I've seen in practice on actual take offs and in simulator sessions, is a split between crewmembers. In the sim, for example, I see a malfunction. The PF is so keyed into the takeoff that when I call "Abort! Abort! Abort!," the pilot continues the takeoff. I've seen this happen under actual conditions. The more interesting question then becomes what to do when faced with a reason to abort, and the other pilot disregards the instruction.

A worldwide generic industry rule, given in various forms, is that one challenges once, and then challenges again. If no response at the second challenge, one assumes incapacitation and takes control. However, that's awfully darn generic, and may be downright unsafe. I've had to do it twice in my career, and on both occasions there was no time to second guess and there was no other choice. But what about on a takeoff roll?

I was once departing LAX in a Learjet with a newly minted captain. He was very, very weak, and I'd been sent with him on the theory that a "strong" (don't laugh; it wasn't my decision) pilot would make up for his deficiencies. This individual was scared to death of flying into LAX; just mention of the place made him nervous. He missed the call to position and hold on 25L, and seemed nearly overloaded. I could tell he was very focused on his takeoff. Just prior to airspeed coming alive I got a master warning and a main cabin entrance door light (forgive me if I get the annunciation wrong; it's been a little while).

I called out the malfunction, and called for an abort. It was within our prebriefed abort criteria, and within the speed envelope. He failed to abort. I called it again, but noted the airspeed rapidly increasing through indicated and then 80 knots. I glanced over my shoulder, noted both the upper and lower door handles forward (door had to be locked, it was probably a handle not fully down or a microswitch issue). Satisfied that continuing was far safer than trying to wrestle the airplane away from him and execute a high speed abort, we continued. I called V1, rotate, and called positive rate.

No response. Again I called positive rate. No response. I said "I have your gear," and raised his gear. The remainder of the initial after takeoff was the same way. After the after takeoff checks were complete, I poitned at the master warning and then the door light, and repeated, "You ARE aware we have a door ligth and a master warning light?"

For the first time he saw it, and I could see him nearly panic. He completely lost his focus, demanding to know "what shall we do? What should I do? We're going to abort! Declare an emergency, let's do a 180 and land!" Absolutely useless.

I told him we were airborne, continue the climb, and once we were passed over to the high altitude controller I'd go back and have a look. I did, and upon pressing the lower handle down, the light went out.

Sometimes an abort, even though technically warranted, isn't the wisest choice, nor is insisting on it.

 

[FreightGod]

Yeah, but the guy asking the question seems to be flying ATR42s.

Them things may be a different animal than a high-performance jet.

Never flown an ATR or heavy turboprop, but guessing on a V1 speed of 88 knots, Vr 92..?

On a 12000 feet runway?

Perhaps a safe abort after V1 could be made.

If we painted the same scenario with a B-747-200 @ 833,000 lbs and hot temps and reduced power, ya may not want to even think about aborting close to V1...You may fly, but you may not stop.

 

[avbug]

Perhaps a safe abort after V1 could be made.

W(h)eather or not it can be made, it should NOT be made...that's really the point.

 

[Propnose]

Our call outs are 80kts, v1, & vr. We call them out 5kts ahead as well, simply because by the time you get them out of your mouth, you're there. We fly out of IAD all the time which has very long runways, and we never consider aborting after v1. Our pre-departure briefing is probably like everyone else's - we will abort for any malfunction below 80kts, 80kts to v1 we will abort for engine fire, failure or loss of directional control. After v1 we will go flying and take care of the problem in the air.

 

[CA1900]

Yeah, but the guy asking the question seems to be flying ATR42s.

Them things may be a different animal than a high-performance jet.

Never flown an ATR or heavy turboprop, but guessing on a V1 speed of 88 knots, Vr 92..?

On a 12000 feet runway?

Perhaps a safe abort after V1 could be made.

Then what's the point of calculating it at all? "Perhaps" doesn't cut it. All your runway and performance data is predicated on following the speeds and procedures properly, and that includes continuing if there's a problem after V1. Trying to abort past V1 is inviting disaster.

That was my reason for posting the link to the Mesa accident in Bangor, in fact. They took off from an 11,500-foot runway, with a fairly small and agile turboprop (~17000 pounds). They tried to "abort" after V1 (in fact, right as they got into the air), and they had so much momentum at that speed, they couldn't stop it in time, even with the engines in reverse. They touched back down nearly 8,000 feet down the runway, and ended up ripping open the fuselage after they lost control in the snow.

I don't have the numbers for the ATR, but a full 1900 will have a V1 speed of 107 knots, and rotation at 109. At that speed, an abort is extremely risky.

 

[FreightGod]

Well hell, what is the point.

Lets make it even more extrme then:
Say ya are flying empty in a Cessna Twinahawk, or whatever the lighest twin is>
Ya take of from Edwards Air base with their 15K runway and their 15K overuns.

ya are light and ya loose one after V1, Vr, etc...Ya only burnded 2000 feet taking off, ya got 13,000 feet ahead to land on.

A) Should ya disregard any kind of commn sense and airmanship to try to take this sick bird around the pattern and land becuase the you have passed V1..?

B) Or should you chop the power, select full flaps and land straight ahead?
(If the gear is still down)

We do get paid fairly well to throw the book away from time to time and just fly the plane instead of the book.
Again, if this was a heavy jet, ya don't even want to think about aborting after V1......

 

[DC8 Flyer]

Disregard, I misread, we are talking engine failures.

Here is something "curious". From the DC8 chats at 220K pounds
V1 120, VR 125, V2 143. At 325K pounds (max gross) V1, VR, and V2 are 142, 152, 169. I know that the 325K numbers are good for TOL on a "cool" day. So if I am taking off at 220K my V2 is the same as the 325K's V1. The airplane will stop on the runway if the abort is at 142 knots at 325K, why wont the airplane stop on the runway at V1 + 15 at 220K pounds?? Takeoff power is temp based, not weight based (for max that is).

Not advocating aborting above V1 for an engine failure, I just think it is a new way to look at your speeds and your options should you need it.

 

[avbug]

Nothing in aviation is absolute. If there is a question if the airplane will or will not fly, ABORT!

I believe I said that...when I said every situation is unique. However, departing from a briefed takeoff is far more likely to cause problems, and high speed aborts statistically are far more likely to end up badly. Once in a blue moon something occurs that demands an abort anyway...but very, very rarely.

I've had several occasions to experience genuine priority moments during the takeoff roll, and have both aborted and continued...but attempting to abort after I've made the decision to continue would have ended badly in virtually every case.

Those extremely rare moments might occur in which one can and should still get stopped; jammed controls may certainly be among them...again, rare, rare moments, and far, far more the exception than the rule...by orders of magnitude.

 

[DC8 Flyer]

I believe I said that...when I said every situation is unique. However, departing from a briefed takeoff is far more likely to cause problems, and high speed aborts statistically are far more likely to end up badly. Once in a blue moon something occurs that demands an abort anyway...but very, very rarely.

I've had several occasions to experience genuine priority moments during the takeoff roll, and have both aborted and continued...but attempting to abort after I've made the decision to continue would have ended badly in virtually every case.

Those extremely rare moments might occur in which one can and should still get stopped; jammed controls may certainly be among them...again, rare, rare moments, and far, far more the exception than the rule...by orders of magnitude.

Absolutely right, BUT, those are, I think, what is going to end up in disaster more ofter than engine failures. The DC10 out of ORD, if the FO had not pitched to V2, the airplane would have most likely been able to limp around, but following procedure allowed the slats to retract and thus the crash. Im not advocating anarchy, but I am very much against robotism. Think outside the box, take off briefings should be short and sweet, not this below 80 knots, blah blah blah, above 80 knots blah blah blah. I think that programs everyone to go or not based on a set of standards and if something pops up that isnt within those standards, the programming takes over and the decision to continue may be made when a decision to stop would have been better.

 

[CA1900]

Once in a blue moon something occurs that demands an abort anyway...but very, very rarely...

Those extremely rare moments might occur in which one can and should still get stopped; jammed controls may certainly be among them...

Exactly. "Well, we have lots of runway left" should not be one of the factors in whether to abort after V1. "It won't fly" is about the only reason I can think of for a post-V1 abort. And those are extremely rare. As others have pointed out, high-speed aborts tend to end badly, whatever the reason.


We had just such an abort a while back -- one of our planes got to rotation speed, and the elevator wouldn't move. They aborted at a little over 100 knots on a 7000-foot runway. Fortunately it was dry and the airplane was light, so they were able to stop it in time.

As it turns out, the trim wheel was removed for a maintenance procedure, and was reinstalled 90 degrees from where it was supposed to be. Unfortunately, the trim index is on the knob, not the pedestal, so the crew had no way to know. (Raytheon's poor maintenance manual doesn't directly address this, as I understand it. Ours does -- now.)

The elevator was trimmed severely nose-down, hence the elevator feeling jammed on takeoff. We've added a procedure to the crew-change preflight to run the trims to their stops and back to center, to be sure they stop at the red lines, and that should catch it if it ever happens again.

 

[100LL... Again!]

If there is a serious concern as to whether the aircraft could actually fly, I would consider such an abort.

An extreme example might be a collision with wildlife. Anyone see the posters with the bizjet that is severely damaged by an elk, I think?

That said, COULD you abort a slower turboprop on a very long runway even after getting airborne? Sure, propbably, but why would you want to?

These are transport category aircraft, and it is important not to fly them with a GA light-twin philosophy.

 

[100LL... Again!]

We had just such an abort a while back -- one of our planes got to rotation speed, and the elevator wouldn't move. They aborted at a little over 100 knots on a 7000-foot runway. Fortunately it was dry and the airplane was light, so they were able to stop it in time.

I that situation, I think the crew made the right call. I've met some pilots that mechanically think that V1 is inviolable under any and all circumstances. Too much book-learnin' and not enough common sense.

 

[Groucho]

V1 is not a hard number anymore

With the advent of computerized weight and balance and performance data, V1 is now computed on a specific airplane, weight, temperature, and runway condition at our airline. There is no specific hard number. It can be increased for incrased cliimb performance, if runway lenght and aircraft weight are not limiting. It can be reduced with an incrased flap setting for contaminated runways to improve stopping capability.

For high hot and heavy operations, such as Las Vegas in August, V1, V2 will be upagainst the limiting tire speed, runway length considered, to improve second segment climb performance.

The fact of the matter is, is that with computerized performance data V1, V2 and other factors can be computed on a case by case basis to optimize performance.

To answer the orginal question, yes V1 can be increased to improve climb performance or some other paramater. You do not however change the way we handle V1. Once computed, by whatever method, prior to V1 for an engine failure, we stop. After V1 we continue the takeoff.

I hope we are all confused now at a much higher leve.