bristolflyer
Posts: 2103
Joined: Fri May 14, 2004 1:35 am

Easy Runway Length Question

Sat Mar 05, 2005 12:39 pm

Couldn't fit a relevant sentance in the Topic field.

Are there any/many runways out there at major airports where the pilot could be at take off speed (in any aircraft) and still abort if there was a problem? I think it's called V1 - the point of no return - is that correct?

When I say 'any aircraft' I mean the one with the longest take off distance - I'm guessing 747 or A340.

BF

PS I once saw a crop duster plane doing a demo in the UK that took off at 26mph, I guess that could take off and land about a dozen times on an average runway!
Fortune favours the brave
 
corey07850
Posts: 2335
Joined: Wed Feb 04, 2004 4:33 am

RE: Easy Runway Length Question

Sat Mar 05, 2005 1:00 pm

Yes.... Occasionally Vr and V1 can be equal... This would depend on favorable weather conditions, runway length, aircraft weight, among other factors......
 
PhilSquares
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Joined: Sun Mar 28, 2004 6:06 pm

RE: Easy Runway Length Question

Sat Mar 05, 2005 1:32 pm

It is not uncommon on twin engine transport aircraft such as the 75/320 to have V1 and Vr equal.

However, on the 744 you will always have a V1 VR V2 being different speeds. V1 and Vr will never be the same as the case of a twin.
Fly fast, live slow
 
Capt.Fantastic
Posts: 834
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RE: Easy Runway Length Question

Sat Mar 05, 2005 1:38 pm

Many vairables are factored into consideration when deciding whether or not to reject a take-off.

A TWA L-1011 that aborted take-off after Vr at JFK is an interesting example of what could happen - If I recall correctly, the pilot did rotate, but than decided to abort for some reason. The airplane was over landing weight and the main gear punctured the wing upon contact w/ the ground.

I recall after that Lauda Air 767 crash over Thailand, 767s with PW4000 engines were not using thrust reverse for a brief period, at least AA 767s. During that time, they would select a longer departure runway because in the event of a rejected take-off, they could not use thrust reverse. (I don't remember if there was an Airworthyness Directive or if this was just something AA did for precautionary reasons.)
 
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Starlionblue
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RE: Easy Runway Length Question

Sat Mar 05, 2005 2:05 pm

I recall after that Lauda Air 767 crash over Thailand, 767s with PW4000 engines were not using thrust reverse for a brief period, at least AA 767s. During that time, they would select a longer departure runway because in the event of a rejected take-off, they could not use thrust reverse. (I don't remember if there was an Airworthyness Directive or if this was just something AA did for precautionary reasons.)

This must have been precautionary since the effect of reversers is never included in braking calculations. They are just a bonus.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
CRJ200Mechanic
Posts: 200
Joined: Fri Feb 18, 2005 5:37 pm

RE: Easy Runway Length Question

Sat Mar 05, 2005 2:43 pm

Quoting Starlionblue (reply 4):
They are just a bonus


I didn't know TR's were a bonus. I thought that they were always included
Always remember the responsibilies you hold with an A&P license
 
eadc8
Posts: 105
Joined: Sat Mar 05, 2005 2:03 pm

RE: Easy Runway Length Question

Sat Mar 05, 2005 2:56 pm

I've been reading this forum for quite sometime now and I did not think that this would be my first post, but here it goes:

This is in response to Capt.Fantistic's comments about the TWA L-1011 crash at JFK. That particular flight was departing from 13R bound for SFO in Aug of '92. The control tower notified the Capt that "your tail is on fire" just as he was lifting off the ground. If my memory serves me correct, he had climbed to about 100 ft and decided to put her back down on the runway. He proceeded to do so and the Tristar ran off the runway to the left. Emergency evacuation procedures were implemented and everyone onboard got out alive.
The plane itself was burned beyond recognition, with the exception of the tail. Quite ironic, because the fire started in the tail engine.

As far as the subject of this thread goes, this is a perfect example of how runway length saved the lives of a couple of hundred pax (I don't remember the exact number). 13R/31L at JFK is roughly 15,000 feet long. My guess is he probably rotated somewhere between 7000 and 9000 feet.
Once he was informed that he was on fire, he obviously realized that he had plenty of runway to set her back down and stop.

If the runway would have been any shorter, he would not have made the decision that he did. He would have had no choice but to continue his climb and then try to make an emergency landing. Who knows what the results would have been, but my guess is that they would not have been good.
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LeanOfPeak
Posts: 496
Joined: Thu Oct 21, 2004 2:18 am

RE: Easy Runway Length Question

Sat Mar 05, 2005 3:10 pm

CRJ200Mechanic:

FAR accelerate-stop distances are certified on two bases.

On a dry runway, you are not allowed to use thrust reversers. On a wet runway, you are.
 
andz
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RE: Easy Runway Length Question

Sat Mar 05, 2005 3:10 pm

Quoting CRJ200Mechanic (reply 5):
I didn't know TR's were a bonus. I thought that they were always included


It makes sense not to include them, as one of the reasons for aborting a take off is engine failure and hence no reverse thrust available.
After Monday and Tuesday even the calendar says WTF...
 
HaveBlue
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Joined: Fri Jan 30, 2004 3:01 pm

RE: Easy Runway Length Question

Sat Mar 05, 2005 3:24 pm

I believe you, but strangely its not in the NTSB records. I used the Database indexed by month, and nothing for it. I then queried any L-1011 accident/incident from 1982 to present, and in 4 pages of replies not one was at JFK.

Weird.
Here Here for Severe Clear!
 
eadc8
Posts: 105
Joined: Sat Mar 05, 2005 2:03 pm

RE: Easy Runway Length Question

Sat Mar 05, 2005 3:42 pm

I believe you, but strangely its not in the NTSB records. I used the Database indexed by month, and nothing for it. I then queried any L-1011 accident/incident from 1982 to present, and in 4 pages of replies not one was at JFK




Is it possible that because there were no fatalities it is not listed? Though that really doesn't make sense.

I have a copy of the NY POST with the headline "THEY ALL LIVED", with a picture of the wreckage on the front page. I also have personal video of the wreckage that myself and a friend took two or three days after it happened.

I'm not saying this to defend myself, you already stated that you believe me. But, I just find it weird that there could be no online record of this incident

[Edited 2005-03-05 07:56:20]
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Starlionblue
Posts: 17208
Joined: Fri Feb 27, 2004 9:54 pm

RE: Easy Runway Length Question

Sat Mar 05, 2005 10:01 pm

"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
1MillionFlyer
Posts: 1937
Joined: Wed Sep 08, 2004 8:55 am

RE: Easy Runway Length Question

Sat Mar 05, 2005 10:08 pm

I was on DL MD-11 flight 39 from AMS to ATL that had smoke in the cabin and made an emergency landing at IAD in December 2002 that does not show up in the NTSB database either.
Golf Foxtrot you are cleared for departure
 
bristolflyer
Posts: 2103
Joined: Fri May 14, 2004 1:35 am

RE: Easy Runway Length Question

Sat Mar 05, 2005 10:26 pm

I often wondered what would have happened if the captain had tried to put the 'Paris crash' AF Concorde back down on the deck once he realised that he was on fire. I know he was past the point of no return but with the fire raging that badly crashing through a few fences at the end of the runway seems preferable. I guess he wouldn't have known how bad things were at that stage.

BF
Fortune favours the brave

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