Noises heard at 41 seconds

Good discussion and great points all around.

Yes, you're right that an ejection seat and a tail hook give a military fighter a completely different set of options...and that was my point that "absolutes" like "you ALWAYS continue the takeoff after V1" aren't necessarily absolutes. That in other aircraft and other circumstances that may not necessarily be true.

Although today's fighters have zero-zero ejection seats, there is always inherent risk when you pull the handles, too. Like with a high speed abort, you have to assess and compare risks. Also as with other emergencies you have to decide beforehand what you will and won't eject for. We have an adage that goes "the decision to eject is made on the ground."

But the fact of the matter remains, you need to accept that you've got a good chance of going off the runway after V1. Now as you said, that might be preferable to taking the plane airborne, but what if you're on a 7,000' runway with a 100' drop off at the end of the runway? I'd take almost any problem into the air as opposed to taking that drop off at the end of the runway, as that's going to be certain to cause a hell of a lot of damage to the aircraft and I'm willing to bet get everybody on the airplane killed.

Again, this is a decision that you make given the set of circumstances...not a binary one based only on a number in the TOLD.
 
I have to go with the V1 continue takeoff crowd on this one. While Pat has a valid point about a situation where you still have 7000 feet remaining, I personally prefer to continue the takeoff if it happens within 5 knots of V1. Granted, you may not want to take a problem flying, but when V1 rolls around, you're going to have a lot more trouble getting an airplane stopped than just flying it around the pattern and coming back for landing.

Of course the airplanes I rountinely fly can fly a long time in one engine. Your mileage may vary depending on your airframe.

And comparing an engine failure at V1 to the DC-8 crash in Miami is apples to oranges.
 
I like to not have to think. At v1, unless the airplane physically does not rotate or we are asphyxiating from fire/smoke in the cockpit, we are flying.

Because at v1, there is almost nothing that would necessitate an abort to the point that it would be safer than a quick trip around the pattern.

Especially when you factor in human decision making ability, your assessment of what is wrong (how do you KNOW it's a structural fire that's gonna burn through the control cables and not a coffee pot that got too hot), and the amount of time you have to make that call.
 
I like to not have to think. At v1, unless the airplane physically does not rotate or we are asphyxiating from fire/smoke in the cockpit, we are flying.

Because at v1, there is almost nothing that would necessitate an abort to the point that it would be safer than a quick trip around the pattern.

Especially when you factor in human decision making ability, your assessment of what is wrong (how do you KNOW it's a structural fire that's gonna burn through the control cables and not a coffee pot that got too hot), and the amount of time you have to make that call.

:yeahthat:

I'm even of the opinion that, at least in the Lears and Citations that I fly, it's better to get rid of the 80 knot decision mantra as well. We typically only have a short time between the 80 knots and V1 calls anyway, so I say forget about that "after 80 knots we'll only abort for loss of engine, engine fire, loss of directional control, or T/R deployment" stuff. I brief that we'll abort for anything before V1, because by the time I decide if that blinking light I see out of the corner of my eye is just a generator failure, or the first indication of an engine that's eating itself up, I'm probably already past V1. Others might make a different decision based on the characteristics of their airframes, but that's the way I approach it in the airplanes that I command.
 
Hmmm. An interesting, on topic thread with good points made all around and no name calling. Who are you and what have you done with jetcareers?
 
Hmmm. An interesting, on topic thread with good points made all around and no name calling. Who are you and what have you done with jetcareers?


Its about time. Frankly I like detailed discussions on the "absolutes" or the "this is how it should be done" topics because it makes for interesting discourse that everybody walks away from a little more knowledgeable.

I think being airframe and mission specific is incredibly important in this discussion, stevec was talking about the acceleration rates being so high that 80 - v1 is so fast that there's not really much time to even think about it, whereas at 80kts in the 1900, there's still plenty of time to v1 (couple seconds at least). Further, we'd get faulty annunciations in ours all the time. We'd get {L/R Bl. Air Fail} sometimes for no reason (electrical gremlins, the Bleeds always worked great) and the temptation to abort was great, but as soon as it appeared it was gone, just a phantom flickering. If we'd have aborted at 80kts to v1, we'd have done so for no reason. We'd get a {Bat. Charge} light all the time too, which would be disconcerting.
 
Although today's fighters have zero-zero ejection seats, there is always inherent risk when you pull the handles, too. Like with a high speed abort, you have to assess and compare risks. Also as with other emergencies you have to decide beforehand what you will and won't eject for. We have an adage that goes "the decision to eject is made on the ground."
I guess the Captains hands coming off the thrust levers at v1 is the transport category aircraft equivalent of "making that decision on the ground". It is probably the best decision 99.9% of the time, and very few people would have the presence of mind to think about anything other than safely flying the aircraft off the ground in the very limited amount of time. So while I agree we are not robots, as you have pointed out, some things decisions need to be made beforehand.

On another note, I had a buddy that flew A-6s. I remember discussing the differences between TACAIR EPs and ours. The NATOPS boldface procedures were somtimes very short. (It has been awhile, but as I remember...)

Engine fire
1. Confirm by secondary indications.
2. eject

Electrical fire
1. eject

Departure below x feet agl
1. eject
 
Why are we speculating on whether or not this crew rejected past V1 when there's not even a preliminary report out yet?

I always thought V1 was the speed at which you were committed to flying if an engine failed, due to the inability to stop on the remaining runway if you aborted at that speed or higher.

Sometimes, but not always. If V1 and Vr happen to be different numbers, then that's a good clue it's impossible to stop after V1.

V1 could be selected from a range of values depending on whether you (or your company) "go" oriented or "stop" oriented. In the military, we calculate a speed that is greater than or equal to Vmcg and CEFS but less than or equal to Vrotate, Vrefusal, and VBmax. 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? Vrefusal is another number we compute that does actually represent the speed you could accelerate to and then stop on the remaining concrete. On long, dry runways this speed is usually higher than V1 because you'd be flying by then anyway. However, on short wet runways this speed will be controlling and you had better abort prior to then or you're not stopping on the runway.

With all that said, there's a reason we have a V1; pass it and you're going flying.
 
Anyone that uses flex thrust on a CRJ on a short runway has had this thought, I know I have:

"Holy crap. That's all the runway that's left at V1?"

Having to stop this thing right at V1 taking off in somewhere like Panama City would have me sucking my seat straight into my colon. I'm not even gonna THINK about aborting a takeoff AFTER V1. Even flex thrusting in DTW, you're a pretty decent ways down that 12,000 ft runway. If you're doing Flaps 8 instead of Flaps 20, you're at about 144 kts on top of that.

Like most everyone else has said, except in some extemely rare occasions, getting off the ground and coming back to land is safer than a high speed abort.
 
A -200 takes around 2000'-3000' to actually bring to a stop for touchdown upon landing. I would think it could be stopped in that or less when aborting, especially because you are getting on the brakes and thrust reversers immediately.
 
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/airline-pilot-knowledge-base/12521-v1-cuts-checkrides-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 (?).

a 757 driver over at APC said:
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:

Hacker15e in a post on APC said:
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.
 
A -200 takes around 2000'-3000' to actually bring to a stop for touchdown upon landing. I would think it could be stopped in that or less when aborting, especially because you are getting on the brakes and thrust reversers immediately.

Sure, it CAN be done, but when you're rotating while QUICKLY coming up on the TDZ for the opposite end of the runway, it gets the blood flowing. Just b/c it can be done doesn't mean I'm itching to do it.
 
Hacker,

The part 121 definition for v1 would be your Critical Engine Failure Speed.

IE the max speed at which it can reach and be stopped in the ASD.

and

the min speed following a CE failure where it can continue the takeoff with the obstacle clearance requirements being met.

Both criteria have to be met. It may or may not resemble a balanced field condition, and it will be above vmcg. So below it, you abort and above it you go.
 
:yeahthat:

I'm even of the opinion that, at least in the Lears and Citations that I fly, it's better to get rid of the 80 knot decision mantra as well. We typically only have a short time between the 80 knots and V1 calls anyway, so I say forget about that "after 80 knots we'll only abort for loss of engine, engine fire, loss of directional control, or T/R deployment" stuff. I brief that we'll abort for anything before V1, because by the time I decide if that blinking light I see out of the corner of my eye is just a generator failure, or the first indication of an engine that's eating itself up, I'm probably already past V1. Others might make a different decision based on the characteristics of their airframes, but that's the way I approach it in the airplanes that I command.

Great thread and info. :yeahthat: I also 100% agree with this. My takeoff breif is JUST like this.
 
Just for information sake, the stopping distance required after a V1 reject does not take into account using reverse thrust, at least not at Continental. Having both engines operating and using reverse would certainly cushion your stop distance should that ever be a consideration. I am generally a "Go Mode" captain which I brief that way. Even at slower speeds I like to press on unless there is a compelling reason not to. An amber warning light is not overly compelling to me and like an old captain once told me " If Boeing thought it was that important they would of made it a red light." I agree with most here and can't imagine aborting a takeoff after V1 unless I felt there was no other option.
 
Great thread and info. :yeahthat: I also 100% agree with this. My takeoff breif is JUST like this.

Remember, he's in a Citation/Lear with V1 being fairly close to 80kts.

At the airline you fly at do the FOs perform the aborts? I ask because at many airlines it is the captains call and also he/she who performs the abort procedure.

Additionally, you fly a pretty modern aircraft, does the plane inhibit many of the warnings at high speeds? I know my aircraft inhibits certain messages at V1 minus a certain speed.

Have you ever had a spurious message go off above 80kts? I've had a bag door indication before V1 and continued. Aborting at 115kts would have been much riskier than continuing. In my head it wasn't a difficult choice because it didn't fall into a fire, power loss, directional control issue. I looked, the message wasn't one of those, I said "Continue" and that was it.

Sorry, I guess I'm just thinking that if someone briefed me that they're going to abort for anything below V1, we'd chat about it. There are just too many runways where we'd be aborting with a few thousand feet remaining for non emergency items that would be easily handled airborne.
 
For us it is CA's call on the abort. After we set the power CA has his hand on the power levers. The Saab also has a take off inhibit which limits the amount of erroneous annuciator. I brief most of my FO's that we will only abort for engine fire, failure, and controllablity issues. Saab is part 25 certified and you have TLR data that guarantee's your performance if you follow the procedures layed out(configuration, #'s etc.). However if you do have a structural failure you have to become a pilot and take what ever action you feel is necessary. For and engine failure at/after V1 we are flying period.
 
As it would go...

" Any problems or warnings below V1, pilot noticing bring it to my attention. It will be my decision to continue or abort. If I do abort, it will be "MY Controls, ABORT ABORT ABORT" You coordinate with ATC, If it is significant we will stop on the runway, otherwise take it clear and run the checklists. Engine Failure before V1 stop on the Runway, After V1, standard * Profile Memory items at 1000 feet. Bring it back here and call it a day."

Can't think of many reasons why I would want to abort past V1 unless i left the control lock in :banghead:

Used to make an 80kt brief... pertaining to RKD, and "poor" reported braking action. The other 1900 guys know why RKD got that :)

I will be interested to see exactly what happened though.
 
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/airline-pilot-knowledge-base/12521-v1-cuts-checkrides-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 (?).



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:



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.

There's the Air Force way, and then there's the everybody else way; why they always have to be different, who knows, but it can be a pain in the arse to keep the two distinct when you do both. In any event, I'll be furloughed in a few days anyway so looks like I'm back to the military way!
 
Anyone that uses flex thrust on a CRJ on a short runway has had this thought, I know I have:

"Holy crap. That's all the runway that's left at V1?"

Was just thinking that coming out of Norfolk yesterday.

As for Lear Jets, it's still situational. With less than 5000' runways in 24s, 25s and 35s, there's no way you'd abort after 80 knots - V1 is only a second or two away at 110-120 knots. Over 5000' the thing can get airborne and land in that distance but your decision has to be instant because of how quickly you accelerate - even on a single engine. Again, a good take-off briefing for the situation would cover it well.
 
way back when I was in the USAF we had 'minimum acceleration checks' which have never been used in the airlines or gen av to my knowledge. However, I began timing takeoff and all things being equal, from time of application of takeoff thrust (including using reduced thrust when applicable), you are rotating after about :30 seconds. If you go beyond that, you are heavy, it is hot, it is high, the runway is contaminated or a combination of all. At DIA and ABQ it was not unusual to have a takeoff roll of :45 seconds or greater.

The question is.. why the abort after V1.


Everybody... look at were the skid marks begin... I think I saw them start near the end of the touchdown zone (less then 2,000 feet down the runway). SO, if it took me 41 seconds to get that far, I think I might abort because I am not getting enough thrust.

41 seconds must be from when they appied power to taxi onto the runway for takeoff. I don't think they were above V1....
 
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