MK Airlines B747 crash at Halifax
Join Date: Jul 2000
Location: Hamburg,Germany
Posts: 58
Likes: 0
Received 0 Likes
on
0 Posts
very interesting discussion.
reg. V1:
maybe it depends on the airport whether you interrupt
your take off run after v1 (what is behind the runway should be
a main factor for such a decision ...)
i still can't understand this accident. the CVR surely would
have given the info. to my knowledge FDR and CVR are located
in the back of a plane. as the back separated from the rest of the plane before it finally crashed, i still can't see why the CVR is
unreadable. but what do i know ?
will we ever know what really happened ?
reg. V1:
maybe it depends on the airport whether you interrupt
your take off run after v1 (what is behind the runway should be
a main factor for such a decision ...)
i still can't understand this accident. the CVR surely would
have given the info. to my knowledge FDR and CVR are located
in the back of a plane. as the back separated from the rest of the plane before it finally crashed, i still can't see why the CVR is
unreadable. but what do i know ?
will we ever know what really happened ?
Join Date: Sep 1999
Location: ME
Posts: 5,505
Likes: 0
Received 0 Likes
on
0 Posts
Takeoff thrust is determined between 60-80 KIAS, if A crew initially selected 1.3 EPR prior to 80 KIAS, and then selected 1.6 EPR around V1, would they actually have their desired takeoff THRUST? Or would they just have the same EPR value?
747FOCAL
Would you please expand on this They teach us that V1 is the no go, when in reality there is a whole bunch of buffer/slop in there, what exactly do you mean by a WHOLE BUNCH?
Mutt.
747FOCAL
Would you please expand on this They teach us that V1 is the no go, when in reality there is a whole bunch of buffer/slop in there, what exactly do you mean by a WHOLE BUNCH?
Mutt.
They teach us that V1 is the no go, when in reality there is a whole bunch of buffer/slop in there. So what if you buy the field, farm or highway beyond the end of the runway. Chances of surviving increase dramatically if you never leave the ground.
The data has shown that continuing an attempted flight beyond V1 is statistically safer than attempting an abort. Of course you can cite what ifs , but lacking complete and total knowledge of the situation the crew is advised and hopefully taught to continue.
I have no problem with a crews decision making process based on knowledge of the surronding circumstances, but I would be very unhappy to be flying behind a crew that when faced with a what's going on ? circumstance decides to try an abort above V1
Join Date: Aug 2003
Location: Skagness on the beach
Posts: 882
Likes: 0
Received 0 Likes
on
0 Posts
Mutt,
All manufacturers and mod outifts inject confidence margins into their products. Even the FARs build a safety buffer into how balanced field length is calculated. Balanced Field Length is actually 115% of actual per the FARs. So right there you have 15% slop in the calculation. Add on the other 5-10% of what the manufacturer threw on there and your actual field length requirement is somewhere between 20-25% less than what you calculate.
In this case the runway is 8100 ft or so long. That means there was anywhere from 1600 to 2000 ft of slop built into the takeoff calculation.
I am not trying to say these guys made any mistakes by continueing the takeoff roll. That what we are tought to do. But in some cases if you had it to do over again, slamming the brakes on and maybe hitting something at a slow speed at the end of the runway was smarter then leaving the ground. The concorde crash was a good example of an instance where the plane should have never left the ground regardless of the consequence of crashing into something at the end of the runway.
The problem is, it's after the event when you figure out what you should have done.
All manufacturers and mod outifts inject confidence margins into their products. Even the FARs build a safety buffer into how balanced field length is calculated. Balanced Field Length is actually 115% of actual per the FARs. So right there you have 15% slop in the calculation. Add on the other 5-10% of what the manufacturer threw on there and your actual field length requirement is somewhere between 20-25% less than what you calculate.
In this case the runway is 8100 ft or so long. That means there was anywhere from 1600 to 2000 ft of slop built into the takeoff calculation.
I am not trying to say these guys made any mistakes by continueing the takeoff roll. That what we are tought to do. But in some cases if you had it to do over again, slamming the brakes on and maybe hitting something at a slow speed at the end of the runway was smarter then leaving the ground. The concorde crash was a good example of an instance where the plane should have never left the ground regardless of the consequence of crashing into something at the end of the runway.
The problem is, it's after the event when you figure out what you should have done.
Join Date: Sep 1999
Location: ME
Posts: 5,505
Likes: 0
Received 0 Likes
on
0 Posts
747FOCAL
Would you please give me the actual FAR reference for this Balanced Field Length is actually 115% of actual per the FARs
In this case the runway is 8100 ft or so long. That means there was anywhere from 1600 to 2000 ft of slop built into the takeoff calculation. This is so ludicrous that its not even funny!
Please refer to:
FAR 25-109
FAR 25-113
An aircraft manufacturer MAY build in a greater buffer than required by the FAR’s, however flight crews are not made aware of that buffer and therefore are not in a position to count on it!
The Boeing Jet Transport Performance Manual states that the B747-100/200/300 were certified using reaction times for Brake Application plus thrust reduction and the time increment from engine failure to spoiler activation. For certification, 1 second was added to each reaction time to account for in service delays in pilot reaction
Based on how Boeing certified that particular model of aircraft, I totally fail to see where you get the idea of a whole bunch of buffer/slop
We operate B747’s from FIELD LENGTH LIMITED runways at the RTOW, it is totally wrong to give the impression that there is 1600-2000 feet built into the takeoff calculation. That luxury doesn’t exist!
Mutt.
Would you please give me the actual FAR reference for this Balanced Field Length is actually 115% of actual per the FARs
In this case the runway is 8100 ft or so long. That means there was anywhere from 1600 to 2000 ft of slop built into the takeoff calculation. This is so ludicrous that its not even funny!
Please refer to:
FAR 25-109
FAR 25-113
An aircraft manufacturer MAY build in a greater buffer than required by the FAR’s, however flight crews are not made aware of that buffer and therefore are not in a position to count on it!
The Boeing Jet Transport Performance Manual states that the B747-100/200/300 were certified using reaction times for Brake Application plus thrust reduction and the time increment from engine failure to spoiler activation. For certification, 1 second was added to each reaction time to account for in service delays in pilot reaction
Based on how Boeing certified that particular model of aircraft, I totally fail to see where you get the idea of a whole bunch of buffer/slop
We operate B747’s from FIELD LENGTH LIMITED runways at the RTOW, it is totally wrong to give the impression that there is 1600-2000 feet built into the takeoff calculation. That luxury doesn’t exist!
Mutt.
Join Date: Dec 1999
Location: Ottawa, Ontario, Canada
Posts: 330
Likes: 0
Received 0 Likes
on
0 Posts
747FOCAL,
I wasn't questioning your account of the crew's actions in setting the EPR before and during TO, only your interpretation of the underlying rationale for their actions. You think that the crew member who advanced the throttles at around V1 would have firewalled the throttles only if he didn't know what the proper EPR setting was. Further, you imply that he believed the correct EPR setting for TO was 1.6 , so that when he noticed at around V1 that the EPR was at 1.3, he raised the setting to 1.6. That's a 23% increase - pretty hefty IMHO.
Is it normal practice for a crew to adjust the PWR setting by such a large amount at such an advanced stage of the TO roll?
I can only conclude that the crew must have grossly underestimated the TOW.
Rockhound
I wasn't questioning your account of the crew's actions in setting the EPR before and during TO, only your interpretation of the underlying rationale for their actions. You think that the crew member who advanced the throttles at around V1 would have firewalled the throttles only if he didn't know what the proper EPR setting was. Further, you imply that he believed the correct EPR setting for TO was 1.6 , so that when he noticed at around V1 that the EPR was at 1.3, he raised the setting to 1.6. That's a 23% increase - pretty hefty IMHO.
Is it normal practice for a crew to adjust the PWR setting by such a large amount at such an advanced stage of the TO roll?
I can only conclude that the crew must have grossly underestimated the TOW.
Rockhound
Join Date: Aug 2003
Location: Skagness on the beach
Posts: 882
Likes: 0
Received 0 Likes
on
0 Posts
Okay I actually said that kinda wrong........
FAR 25.113 Takeoff Distance and Takeoff Run.
[(a) Takeoff distance on a dry runway is the greater of--
(1) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 35 feet above the takeoff surface, determined under Sec. 25.111 for a dry runway; or]
(2) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to the point at which the airplane is 35 feet above the takeoff surface, as determined by a procedure consistent with Sec. 25.111.
[(b) Takeoff distance on a wet runway is the greater of--
(1) The takeoff distance on a dry runway determined in accordance with paragraph (a) of this section; or
(2) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 15 feet above the takeoff surface, achieved in a manner consistent with the achievement of V2 before reaching 35 feet above the takeoff surface, determined under Sec. 25.111 for a wet runway.
[(c) If the takeoff distance does not include a clearway, the takeoff run is equal to the takeoff distance. If the takeoff distance includes a clearway--
(1) The takeoff run on a dry runway is the greater of--
(i) The horizontal distance along the takeoff path from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, as determined under Sec. 25.111 for a dry runway; or
(ii) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, determined by a procedure consistent with Sec. 25.111.
(2) The takeoff run on a wet runway is the greater of--
(i) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 15 feet above the takeoff surface, achieved in a manner consistent with the achievement of V2 before reaching 35 feet above the takeoff surface, as determined under Sec. 25.111 for a wet runway; or
(ii) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, determined by a procedure consistent with Sec. 25.111.]
If you read the entire section on calculating runway performance one will notice it is all based on worst case scenarios for which they build in conservatism for the pilot of avg skill. Everything is 105 to 115% of actual.
Your accelerate stop distance is based on failing the critical engine at V1. If you know you have all engines then you know your stopping power will stop you before what you calculated.
Maybe you have not noticed or cared, but most commercial aircraft rotate way before where the takeoff calculations told you it should.
Example: MD-80 has a balanced field length comperable to a 767 (~10600 ft @ MTOW 160K). I guarantee you, the MD-80 will accelerate to Vr, reject the takeoff, slam the brakes and full reverse and be stopped again in way less than 10,000 ft.
Rockhound,
If your pretty sure your going to die, I think they will try anything that helps regardless of what point of takeoff you are at.
FAR 25.113 Takeoff Distance and Takeoff Run.
[(a) Takeoff distance on a dry runway is the greater of--
(1) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 35 feet above the takeoff surface, determined under Sec. 25.111 for a dry runway; or]
(2) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to the point at which the airplane is 35 feet above the takeoff surface, as determined by a procedure consistent with Sec. 25.111.
[(b) Takeoff distance on a wet runway is the greater of--
(1) The takeoff distance on a dry runway determined in accordance with paragraph (a) of this section; or
(2) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 15 feet above the takeoff surface, achieved in a manner consistent with the achievement of V2 before reaching 35 feet above the takeoff surface, determined under Sec. 25.111 for a wet runway.
[(c) If the takeoff distance does not include a clearway, the takeoff run is equal to the takeoff distance. If the takeoff distance includes a clearway--
(1) The takeoff run on a dry runway is the greater of--
(i) The horizontal distance along the takeoff path from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, as determined under Sec. 25.111 for a dry runway; or
(ii) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, determined by a procedure consistent with Sec. 25.111.
(2) The takeoff run on a wet runway is the greater of--
(i) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 15 feet above the takeoff surface, achieved in a manner consistent with the achievement of V2 before reaching 35 feet above the takeoff surface, as determined under Sec. 25.111 for a wet runway; or
(ii) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, determined by a procedure consistent with Sec. 25.111.]
If you read the entire section on calculating runway performance one will notice it is all based on worst case scenarios for which they build in conservatism for the pilot of avg skill. Everything is 105 to 115% of actual.
Your accelerate stop distance is based on failing the critical engine at V1. If you know you have all engines then you know your stopping power will stop you before what you calculated.
Maybe you have not noticed or cared, but most commercial aircraft rotate way before where the takeoff calculations told you it should.
Example: MD-80 has a balanced field length comperable to a 767 (~10600 ft @ MTOW 160K). I guarantee you, the MD-80 will accelerate to Vr, reject the takeoff, slam the brakes and full reverse and be stopped again in way less than 10,000 ft.
Rockhound,
If your pretty sure your going to die, I think they will try anything that helps regardless of what point of takeoff you are at.
Join Date: Oct 2004
Location: north of the harbour
Posts: 25
Likes: 0
Received 0 Likes
on
0 Posts
747Focal quote "Maybe you have not noticed or cared, but most commercial aircraft rotate way before where the takeoff calculations told you it should."
Mutt quote: "We operate B747’s from FIELD LENGTH LIMITED runways at the RTOW, it is totally wrong to give the impression that there is 1600-2000 feet built into the takeoff calculation. That luxury doesn’t exist!"
I'm totally with you on that one, Mutt. We are more often than not field length limited, and I don't think I've been surprised yet by the fact that our plane "rotated way before the calculations told us it would". Maybe we just fly the wrong types?
Mutt quote: "We operate B747’s from FIELD LENGTH LIMITED runways at the RTOW, it is totally wrong to give the impression that there is 1600-2000 feet built into the takeoff calculation. That luxury doesn’t exist!"
I'm totally with you on that one, Mutt. We are more often than not field length limited, and I don't think I've been surprised yet by the fact that our plane "rotated way before the calculations told us it would". Maybe we just fly the wrong types?
Join Date: Aug 2003
Location: Skagness on the beach
Posts: 882
Likes: 0
Received 0 Likes
on
0 Posts
Its right there in the FARs.... How you calculate you distance to 35 ft is based on 115% of actual. Its buried in the AFM, but it is there. So no matter what runway you are on, just from the FARs alone there is 15% of buffer or slop. On 8100 ft runway that is 1215 ft or if everything is as it should the aircraft should be at 35 ft around 1200 ft before what you calculated said it should.
Join Date: Oct 2002
Location: Canada
Posts: 108
Likes: 0
Received 0 Likes
on
0 Posts
747focal:
As a safety person, it is my job to identify how and why unsafe events and conditions occur. Your point is not relevant from a safety perspective. There are many safety buffers built into the way aircraft systems and performance parameters are certified. Those buffers are there to allow for minor errors and ommissions, component wear and tear, and imperfections in human performance. There is no way to quantify where you are in a given circumstance relative to a safety buffer. No professional pilot worth his salt wants to enter the ragged edge between the safety margin and a negative (and maybe deadly) result.
You are taking the focus away from the important issue, which is how and why the MK crew erred in setting the power. Remove that error, and the accident doesn't happen. You can play test pilot if you wish, but I'm not so sure your colleagues and your customers would wish to join you during your experiment. As I said before, unless I'm faced with an un-flyable airplane,when V1 arrives, I am going flying.
SG
As a safety person, it is my job to identify how and why unsafe events and conditions occur. Your point is not relevant from a safety perspective. There are many safety buffers built into the way aircraft systems and performance parameters are certified. Those buffers are there to allow for minor errors and ommissions, component wear and tear, and imperfections in human performance. There is no way to quantify where you are in a given circumstance relative to a safety buffer. No professional pilot worth his salt wants to enter the ragged edge between the safety margin and a negative (and maybe deadly) result.
You are taking the focus away from the important issue, which is how and why the MK crew erred in setting the power. Remove that error, and the accident doesn't happen. You can play test pilot if you wish, but I'm not so sure your colleagues and your customers would wish to join you during your experiment. As I said before, unless I'm faced with an un-flyable airplane,when V1 arrives, I am going flying.
SG
Join Date: Aug 2003
Location: Skagness on the beach
Posts: 882
Likes: 0
Received 0 Likes
on
0 Posts
Safety Guy,
Your missing the point. Go back and read the previous bunch of posts. I am not endorsing changing how we look at how we operate. All I said was that sometimes in hindsight some pilots might choose to throw the brakes on after V1. But in the end at that point it really does not matter.
Your wrong about my collegues and what they will go do with or for me in a real airplane. Modification of what the OEM certified for the airplane is what I do. If I can deviate from what the OEM certified and prove it safe to the regulators I have no problem enhancing the usability of my customer's aircraft. You line pilots think you know everything about what goes into making an airplane safe. There is a whole other group of us out there that do that and it is invisable to you other than you get to go home at night. What the pilots that I deal with will do in an airplane would make 90% of line pilots shat themselves.
Your missing the point. Go back and read the previous bunch of posts. I am not endorsing changing how we look at how we operate. All I said was that sometimes in hindsight some pilots might choose to throw the brakes on after V1. But in the end at that point it really does not matter.
Your wrong about my collegues and what they will go do with or for me in a real airplane. Modification of what the OEM certified for the airplane is what I do. If I can deviate from what the OEM certified and prove it safe to the regulators I have no problem enhancing the usability of my customer's aircraft. You line pilots think you know everything about what goes into making an airplane safe. There is a whole other group of us out there that do that and it is invisable to you other than you get to go home at night. What the pilots that I deal with will do in an airplane would make 90% of line pilots shat themselves.
Join Date: Dec 1999
Location: Ottawa, Ontario, Canada
Posts: 330
Likes: 0
Received 0 Likes
on
0 Posts
747FOCAL,
I don't seem to be making myself understood to you. If that's my fault, I apologize.
However, your last response to me (edited by me)
____________________________________________________
If you're pretty sure you're going to die, I think [you] will try anything that helps regardless what point of takeoff you are at.
____________________________________________________
exactly illustrates my point. Why did the MK crewmember not firewall the throttles instead of merely upping them a few notches from 1.3 to 1.6 EPR?
And my question remains:
Is it acceptable practice for a pilot to correct the power setting by a significant amount (or any amount, for that matter) at as late a stage as VI during the takeoff roll?
I would be really grateful for answer from you experts.
Thanks in advance.
Rockhound
I don't seem to be making myself understood to you. If that's my fault, I apologize.
However, your last response to me (edited by me)
____________________________________________________
If you're pretty sure you're going to die, I think [you] will try anything that helps regardless what point of takeoff you are at.
____________________________________________________
exactly illustrates my point. Why did the MK crewmember not firewall the throttles instead of merely upping them a few notches from 1.3 to 1.6 EPR?
And my question remains:
Is it acceptable practice for a pilot to correct the power setting by a significant amount (or any amount, for that matter) at as late a stage as VI during the takeoff roll?
I would be really grateful for answer from you experts.
Thanks in advance.
Rockhound
747Focal
Dont see any reject after V1 on a field limited runway resulting in a low speed overrun.
Think you spend too much time at zero g zero airspeed, the risks you will end up on fire dead off the end off the runway rejecting are high speed above V1 are significant, espically with an old airframe, old tires, old engines, and a tired crew.
Dont agree with your extra flap idea either, will that improve things for all segments in the case of an engine failure, or you taking about a 4 engine takeoff roll only ?
Oh well ... interested to hear what response you get Safety Guy, I guess we will never know who set those powers, the engineer or pilot
Rockhound
It is common for the flight engineer to trim the power levers at any stage, on the ground or airborne, the pilots will remove their hands from the throttles at V1
All I said was that sometimes in hindsight some pilots might choose to throw the brakes on after V1.
Dont see any reject after V1 on a field limited runway resulting in a low speed overrun.
Think you spend too much time at zero g zero airspeed, the risks you will end up on fire dead off the end off the runway rejecting are high speed above V1 are significant, espically with an old airframe, old tires, old engines, and a tired crew.
Dont agree with your extra flap idea either, will that improve things for all segments in the case of an engine failure, or you taking about a 4 engine takeoff roll only ?
Oh well ... interested to hear what response you get Safety Guy, I guess we will never know who set those powers, the engineer or pilot
Rockhound
It is common for the flight engineer to trim the power levers at any stage, on the ground or airborne, the pilots will remove their hands from the throttles at V1
Join Date: Nov 1999
Location: Mk. 1 desk at present...
Posts: 365
Likes: 0
Received 0 Likes
on
0 Posts
Confused ramblings... confused due to the very recent arrival of an 8lb 1oz Junior Ranger 
V1...
I can see merits in the views of both Flight Safety and lomapaseo - perhaps there *is* some room for a pre-briefed consideration of the options in the event that a problem occurs at or just past V1. The statistics which lead V1 to be considered an unconditional 'fly or die' speed can't be argued, as others have pointed out, and there are dangers with interfering with this mindset. But perhaps there should be a field-specific briefing item to cover the eventuality that the MK crew encountered: a problem that occurs at, or isn't noticed until, V1, and the question that requires a millisecond answer is 'what kind of an accident do we want to have today?'...
EPR...
Not familiar with type; perhaps someone who is can answer this. The MK guys are reported to have set 1.6 at V1. How much more would they have got if they had firewalled it?
EFB...
I use an ADR EFB. JeppView, Jepp FliteStar, Exxon Avitat database... very useful. But not a replacement for common sense.
R1
V1...
I can see merits in the views of both Flight Safety and lomapaseo - perhaps there *is* some room for a pre-briefed consideration of the options in the event that a problem occurs at or just past V1. The statistics which lead V1 to be considered an unconditional 'fly or die' speed can't be argued, as others have pointed out, and there are dangers with interfering with this mindset. But perhaps there should be a field-specific briefing item to cover the eventuality that the MK crew encountered: a problem that occurs at, or isn't noticed until, V1, and the question that requires a millisecond answer is 'what kind of an accident do we want to have today?'...
EPR...
Not familiar with type; perhaps someone who is can answer this. The MK guys are reported to have set 1.6 at V1. How much more would they have got if they had firewalled it?
EFB...
I use an ADR EFB. JeppView, Jepp FliteStar, Exxon Avitat database... very useful. But not a replacement for common sense.
R1
Join Date: Aug 1998
Location: The World
Posts: 388
Likes: 0
Received 0 Likes
on
0 Posts
Safety Pilot
Your quote; “As I said before, unless I'm faced with an un-flyable airplane, when V1 arrives, I am going flying.”
Hmm I lost an engine on a 767 at V1 max wgt and did a RTO and safely stopped with 4000ft remaining. The ‘go’ ‘no go’ decision should also depend upon the circumstances and that’s why maintaining situational awareness is so important. I would question your judgment if you went flying with 7000ft of runway remaining after an engine failure.
Your quote; “As I said before, unless I'm faced with an un-flyable airplane, when V1 arrives, I am going flying.”
Hmm I lost an engine on a 767 at V1 max wgt and did a RTO and safely stopped with 4000ft remaining. The ‘go’ ‘no go’ decision should also depend upon the circumstances and that’s why maintaining situational awareness is so important. I would question your judgment if you went flying with 7000ft of runway remaining after an engine failure.
Last edited by Tan; 18th Nov 2004 at 20:59.
Join Date: Oct 2002
Location: Canada
Posts: 108
Likes: 0
Received 0 Likes
on
0 Posts
Tan:
I accept your point, but you said the failure occurred at V1. There's a little room at V1 for a judgement call. Some days there may be lots of room, as in your situation, but on most others there's not enough for me to even consider stopping once the speed needle reaches the V1 bug, unless I have reason to believe the airplane may not fly.
I have to ask how long that runway was to begin with? If you got a fully loaded 767 to V1 and stopped with that much runway left, I believe you were on a very long runway. Hardly a typical circumstance that most of us find ourselves in on most long haul takeoffs.
I hope that you make a habit of briefing your First Officer that you may reject a takeoff once you've reached V1. It's doubtful that he's expecting it otherwise.
swh:
For the record, I am not involved in the MK investigation. Like all of you, I wait with baited breath for a reasonable explanation.
I accept your point, but you said the failure occurred at V1. There's a little room at V1 for a judgement call. Some days there may be lots of room, as in your situation, but on most others there's not enough for me to even consider stopping once the speed needle reaches the V1 bug, unless I have reason to believe the airplane may not fly.
I have to ask how long that runway was to begin with? If you got a fully loaded 767 to V1 and stopped with that much runway left, I believe you were on a very long runway. Hardly a typical circumstance that most of us find ourselves in on most long haul takeoffs.
I hope that you make a habit of briefing your First Officer that you may reject a takeoff once you've reached V1. It's doubtful that he's expecting it otherwise.
swh:
For the record, I am not involved in the MK investigation. Like all of you, I wait with baited breath for a reasonable explanation.
Join Date: Aug 2003
Location: Skagness on the beach
Posts: 882
Likes: 0
Received 0 Likes
on
0 Posts
swh,
Would you rather be in the air on fire or on the ground? In some cases as has been pointed out, going off the end of the runway into the grass and ending up on fire...........
Its already been calcualted, at max reverse thrust at the point this flight went to 1.6 EPR, they would have ended up with the airplane hitting the bearm at around 60 knots. If the gear had sunk into the mud they would have never made the berm.
Like I have said before this is all hind sight. No fault of this crew. They followed the rules. Sorry to see them go.
Rockhound,
I don't know why the crew only moved the thrust levers to 1.6 when they realized something was wrong. All I have is the data. Death has coverd his tracks on this one.
Would you rather be in the air on fire or on the ground? In some cases as has been pointed out, going off the end of the runway into the grass and ending up on fire...........
Its already been calcualted, at max reverse thrust at the point this flight went to 1.6 EPR, they would have ended up with the airplane hitting the bearm at around 60 knots. If the gear had sunk into the mud they would have never made the berm.
Like I have said before this is all hind sight. No fault of this crew. They followed the rules. Sorry to see them go.
Rockhound,
I don't know why the crew only moved the thrust levers to 1.6 when they realized something was wrong. All I have is the data. Death has coverd his tracks on this one.
Join Date: Sep 1999
Location: ME
Posts: 5,505
Likes: 0
Received 0 Likes
on
0 Posts
747FOCAL,
You may have read the FAR's but you didnt understand them
Note the part about ALL ENGINES OPERATING I will admit that in the 747, this is usually the most limiting factor, however that doesnt mean that its an automatic 15% buffer!
Rockhound
It is common for the flight engineer to trim the power levers at any stage, on the ground or airborne, the pilots will remove their hands from the throttles at V1
Trim??? that certainly doesnt include advancing the throttles from 1.3 to 1.6 EPR! IMHO, trimming means that the PF has set the takeoff power, the FE is making sure that ALL four engines are at the same EPR!
Tan.
We operate flights out of a 15,000 ft runway, based on our normal sector length and aircraft type, crews could very easily get to 100ft, abort the takeoff and land again! Do we teach this? NO. Each situation is different, especially in this world of reduced thrust, so the safest option for 99% of crews is to follow SOP's.
Mutt
Mutt.
You may have read the FAR's but you didnt understand them
(ii) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, determined by a procedure consistent with Sec. 25.111.
I will admit that in the 747, this is usually the most limiting factor, however that doesnt mean that its an automatic 15% buffer!Rockhound
It is common for the flight engineer to trim the power levers at any stage, on the ground or airborne, the pilots will remove their hands from the throttles at V1
Trim??? that certainly doesnt include advancing the throttles from 1.3 to 1.6 EPR! IMHO, trimming means that the PF has set the takeoff power, the FE is making sure that ALL four engines are at the same EPR!
Tan.
We operate flights out of a 15,000 ft runway, based on our normal sector length and aircraft type, crews could very easily get to 100ft, abort the takeoff and land again! Do we teach this? NO. Each situation is different, especially in this world of reduced thrust, so the safest option for 99% of crews is to follow SOP's.
Mutt
Mutt.