Noises heard at 41 seconds

MusketeerMan

Well-Known Member
Regarding the CAL Denver incident...

"The noise was detected 41 seconds after the jet started speeding down a runway at Denver International Airport on Saturday. Four seconds later, one of the crew members called for the takeoff to be aborted, said Robert Sumwalt, a spokesman for the National Transportation Safety Board."

41 seconds after starting to speed down the runway?? Um, I don't fly it, but are there any jets that are going to be accelerating for 41 seconds down a runway and still be on the ground. OK, maybe that was the problem, but am I missing something here or is it the media being the media?

Whatever happened, major kudos to the crew!
 

kellwolf

Piece of Trash
Depends on the weight of the aircraft. If they were doing a static takeoff or had to clear the engines of de-ice fluid, then it's possible. Plus who knows what the definition of "speeding down the runway" is. Is it when the aircraft took the runway? Is it a media way of sensationalizing when the recording started? I know the CRJ takes forever to get up to rotation speed, but it doesn't take 41 seconds from brake release to get there.
 

OldTownPilot

Well-Known Member
Maybe 41 seconds from when they were cleared for take-off?

Yes, 41 seconds would get you much further than 2000 feet down the runway.

99% chance it's the media being the media.
 

B767Driver

New Member
If you took an average speed of 100 kts during the takeoff roll for 41 seconds that would put the airplane about 6800' down the runway. At Denver you can easily use a ton of runway due to the airport elevation. So 41 seconds would put the airplane at a pretty high speed on the runway.

On a 400,000# 767...it probably takes ten seconds or so from pushing the throttles up until you really start to feel the acceleration.

The MD88 took forever to begin rolling after power up.

As I recall...the 737 was pretty responsive though.
 

Yank&BankmyRJ145

New Member
I roll in the power and it takes about 3-6 seconds

"speeding down the runway"-- did I miss a speed limit sign somewhere???:sarcasm:

its the media

And to add to someone else, Denver is high so it does take longer to get up to speed.
 
R

Roger, Roger

Guest
The media do not know what they are talking about. I'm sure the full truth will come out pretty easily as the FDR and CVR are undamaged, and both pilots are still alive.
 

Orange Anchor

New Member
Regarding the CAL Denver incident...

"The noise was detected 41 seconds after the jet started speeding down a runway at Denver International Airport on Saturday. Four seconds later, one of the crew members called for the takeoff to be aborted, said Robert Sumwalt, a spokesman for the National Transportation Safety Board."

Whatever happened, major kudos to the crew!
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.
 

Orange Anchor

New Member
119kts would NOT be above V1 in a loaded 737-500
Possibly. But I thought I had read the aircraft was briefly airborne.. must be incorrect. Does Continental use reduced or min V1s? We did at my old house and there could be a 15-20kt diff between V1 and Vr.

This is why it is necessary to determine the exact definition of V1 for a given carrier and how it is calculated. V1 speeds can vary widely and an assumption of a common meaning can be an error.

And according to this website (sorry but I don't want to go digging in my 200/300/400 manuals or down cobwebbed memory banks), the Vmcg for a -500 is 106kts.
http://www.b737.org.uk/vspeeds.htm#Take-Off_Speeds_
 

MikeFavinger

Hubschrauber Flieger
99% chance it's the media being the media.
its the media
The media do not know what they are talking about.
"The noise was detected 41 seconds after the jet started speeding down a runway at Denver International Airport on Saturday. Four seconds later, one of the crew members called for the takeoff to be aborted, said Robert Sumwalt, a spokesman for the National Transportation Safety Board."
 

Velocipede

New Member
41 seconds after starting to speed down the runway?? Um, I don't fly it, but are there any jets that are going to be accelerating for 41 seconds down a runway and still be on the ground. !
Absolutely. Especially at high density altitude airports. That's why places like Denver have 14,000 foot runways. It takes a LONG time to get a jet up to speed, especially if its heavy and the weather is hot. Now, granted, this was a winter accident, but look at what your dealing with.

As another poster pointed out, you've got 8 to 10 seconds intials spool up time. Technically, you've started the takeoff roll at that point. So that leaves 31 seconds before the Captain decided to abort.

Now, if there was a wheel issue, that may have slowed the acceleration even more. Most training departments now teach that even with a tire blowout near V1 you should continue the takeoff because high speed aborts are generally unsuccessful, especially with failed tires.

Now, if the airplane drifted into the runway edge lights, the same holds true. Unless you're going off the runway, you're probably better to continue the takeoff than try to abort at that point. You'll probably be unsuccessful, if past incidents are the yardstick.

One thing about accidents, we can all learn about flying from them. I encourage everyone to read the final accident investigation reports when they are published. They're public info and availible on the NTSB website. You can learn a LOT from other guys' mistakes.
 

WacoFan

Bigly
In keeping with the general theme of this thread being aborts past V1, what about the Kalitta accident in Belgium. Apparently there was a bird strike and it failed one of the engines and the crew did a post V1 abort and overran the runway. No injuries but a totaled whale. First of all, I thought in a 747 even at MGTOW that losing one wasn't a big deal (relatively speaking)? Second, does anyone know of any post V1 aborts in a transport category aircraft that were successful? Lastly, is there EVER a reason to do a post V1 rejection? Thanks in advance for the answers.
 

ASpilot2be

Qbicle seat warmer
One thing about accidents, we can all learn about flying from them. I encourage everyone to read the final accident investigation reports when they are published. They're public info and availible on the NTSB website. You can learn a LOT from other guys' mistakes.
This is why I loved my aviation safety class. Each member of the class had to do a report on a major aviation accident. I learned about mistakes made, and how to possibly prevent them in the future.
 

Baronman

Well-Known Member
In keeping with the general theme of this thread being aborts past V1, what about the Kalitta accident in Belgium. Apparently there was a bird strike and it failed one of the engines and the crew did a post V1 abort and overran the runway. No injuries but a totaled whale. First of all, I thought in a 747 even at MGTOW that losing one wasn't a big deal (relatively speaking)? Second, does anyone know of any post V1 aborts in a transport category aircraft that were successful? Lastly, is there EVER a reason to do a post V1 rejection? Thanks in advance for the answers.
There was a freedom erj last year that aborted past v1 successfully. I believe the gust lock which holds the elevator did not fully disengage and the pilot was unable to rotate. As other erj drivers know you really need both hands and to pull back almost 90% of the travel to raise the nose. Of course it was an rj and not a 747 and luckily they had the long runways, I believe all the other aircraft systems performed normally.
 

ppragman

FLIPY FLAPS!
There was a freedom erj last year that aborted past v1 successfully. I believe the gust lock which holds the elevator did not fully disengage and the pilot was unable to rotate. As other erj drivers know you really need both hands and to pull back almost 90% of the travel to raise the nose. Of course it was an rj and not a 747 and luckily they had the long runways, I believe all the other aircraft systems performed normally.
I dunno, I think V1 is a good guideline, however, I don't feel that its a golden rule to be followed unthinkingly. A lot of times it depends on the airport, If I'm on a 11,000' runway in the 1900, it only takes about 3500' for us get off, if I lose a motor at exactly v1 (which was usually 114kts) I think its probably prudent to chop the powerlevers and brake to a stop, which the airplane will do no problem, additionally with beta (provided both motors are working for other emergencies) the braking roll is drastically reduced.. Why take that airplane into the air and fight with a dead motor when you still have about 8000' of runway to burn. It will take you more than 30 seconds to reach the end at 114kts or so, so slowing you have plenty of time.

I think we need a new speed called Vbrake or something, which is the speed for the field length that allows you to stop using braking power alone in the remaining runway. It'd have to be calculated before every takeoff, but it'd be useful. There are a lot of accidents on takeoff that I think could be prevented, or the circumstances at least changed for the better if the crews had a bit better idea of their options.
 

jynxyjoe

The Kickin' Chicken!
I dunno, I think V1 is a good guideline, however, I don't feel that its a golden rule to be followed unthinkingly. A lot of times it depends on the airport, If I'm on a 11,000' runway in the 1900, it only takes about 3500' for us get off, if I lose a motor at exactly v1 (which was usually 114kts) I think its probably prudent to chop the powerlevers and brake to a stop, which the airplane will do no problem, additionally with beta (provided both motors are working for other emergencies) the braking roll is drastically reduced.. Why take that airplane into the air and fight with a dead motor when you still have about 8000' of runway to burn. It will take you more than 30 seconds to reach the end at 114kts or so, so slowing you have plenty of time.

I think we need a new speed called Vbrake or something, which is the speed for the field length that allows you to stop using braking power alone in the remaining runway. It'd have to be calculated before every takeoff, but it'd be useful. There are a lot of accidents on takeoff that I think could be prevented, or the circumstances at least changed for the better if the crews had a bit better idea of their options.
If you are afraid of "fighting it" then build a few extra knots on that long ass runway and then rotate. It's a dead engine, it didn't fall off or catch on fire. Do the procedures up in the air, come back and land. Why fight training?
 

wheelsup

Well-Known Member
The reason IMO for the V1 abort go/no-go is to take all guesswork out of it. While you are thinking "hey I have enough runway to stop here even though I am past V1" you are running off the side of the runway. The fact that the airplane may be able to stop after a V1 is irrelevant.
 

WacoFan

Bigly
A lot of times it depends on the airport, If I'm on a 11,000' runway in the 1900, it only takes about 3500' for us get off, if I lose a motor at exactly v1 (which was usually 114kts) I think its probably prudent to chop the powerlevers and brake to a stop, which the airplane will do no problem, additionally with beta (provided both motors are working for other emergencies) the braking roll is drastically reduced.. Why take that airplane into the air and fight with a dead motor when you still have about 8000' of runway to burn. It will take you more than 30 seconds to reach the end at 114kts or so, so slowing you have plenty of time.
OK...going to show my stupidity here, fortunately it will come as a surprise to no one.

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. If that is indeed the case, how would Pat's comment above work? If you have an airplane that can take off within 3,500 feet, on an 11,000 foot runway - how would you calculate V1? You obviously have much more runway than is needed, and if V1 is calculated based upon the stopping distance from a given speed, then V1 would be a very high number on this runway wouldn't it?
 
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