Excel B767 and bmibaby B737 collision at Manchester
Not sure if this has already been said.
When manouvering your Aircraft you should know if you have room to get past any obstruction. If in doubt STOP request assistance. PERIOD
When manouvering your Aircraft you should know if you have room to get past any obstruction. If in doubt STOP request assistance. PERIOD
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Been doing some maths. Using freely available data concerning the wingspan of a B767, the length of a B737-300 and the physical characteristics of the clearance distances at a licensed airport. I’ve taken the latter from CAP168 Chapter 3.
Firstly the half wingspan of a B767 is 23.8m
The length of a B737-300 is 33.4m
S2 protects Taxiway V so is 47.5m from the TWY V centreline.
Assuming 1m collision overlap 23.0 plus 33.0 = 56.0
Minus 47.5 = 8.5m the length the bmiBaby’s nose may be over S2
It’s a further 75m approximately from S2 to T1 and 75m more to the centreline of 24R
Manchester’s runways are 395.0m apart and Taxiway V is midway e.g. 197.5m from the two runways.
Regarding many posters differing views on what constitutes a clearance maybe CAP 168 helps again.
The Code E taxiway strip should be 95m. Within this area there should be no fixed objects that an aircraft of the maximum wingspan can collide with.
However an aircraft, or vehicle, is a temporary obstacle so cannot be assumed to comply with the foregoing.
If as has been said the crew were cleared to hold at T1 and there was an aircraft already there I would be interested to hear why the crew of the bmiBaby a/c elected to stop 66m, minus the aircraft ahead, from the T1 stopbar.?
This meant that 24.9m of their a/c was inside the taxiway V strip.
No doubt the AAIB will do their usual thorough investigation, however the Swiss Cheese safety analogy is already looming in my mind. Several seemingly unconnected events joining up to breach the layers of defence normally in place.
Some questions.
Could this incident have occurred previously?
If nothing is changed , could it happen again?
What needs to be changed to ensure it won’t?
What parallels at other airports can be drawn?
What solutions on a wider basis can we introduce to reduce the risk?
Sir George Cayley
Firstly the half wingspan of a B767 is 23.8m
The length of a B737-300 is 33.4m
S2 protects Taxiway V so is 47.5m from the TWY V centreline.
Assuming 1m collision overlap 23.0 plus 33.0 = 56.0
Minus 47.5 = 8.5m the length the bmiBaby’s nose may be over S2
It’s a further 75m approximately from S2 to T1 and 75m more to the centreline of 24R
Manchester’s runways are 395.0m apart and Taxiway V is midway e.g. 197.5m from the two runways.
Regarding many posters differing views on what constitutes a clearance maybe CAP 168 helps again.
The Code E taxiway strip should be 95m. Within this area there should be no fixed objects that an aircraft of the maximum wingspan can collide with.
However an aircraft, or vehicle, is a temporary obstacle so cannot be assumed to comply with the foregoing.
If as has been said the crew were cleared to hold at T1 and there was an aircraft already there I would be interested to hear why the crew of the bmiBaby a/c elected to stop 66m, minus the aircraft ahead, from the T1 stopbar.?
This meant that 24.9m of their a/c was inside the taxiway V strip.
No doubt the AAIB will do their usual thorough investigation, however the Swiss Cheese safety analogy is already looming in my mind. Several seemingly unconnected events joining up to breach the layers of defence normally in place.
Some questions.
Could this incident have occurred previously?
If nothing is changed , could it happen again?
What needs to be changed to ensure it won’t?
What parallels at other airports can be drawn?
What solutions on a wider basis can we introduce to reduce the risk?
Sir George Cayley
Last edited by Sir George Cayley; 6th Nov 2004 at 20:17.
Completely correct...
The captain has ultimate responsibility for the safety of his aircraft and all persons onboard. (I am not here implying liability in this incident because none of us have the FULL facts).
If I am being marshalled onto stand and am worried about colliding with a ground obstruction, be it a vehicle or an incorrectly parked airbridge, should I blindly obey the instructions of the marshaller and wait for the bang. Then say "He told me to continue"?. NO. If you are in doubt, STOP and request assistance. How can you be sure the marshaller or controller can see what you feel may be a hazard?
Obviously in this incident, there was no marshaller. Likewise NO controller can have blame apportioned to them, because they are not responsible for separation on taxiways. They can request ground assistance if they foresee potential conflicts if, for example, an aircraft is pushed back farther than normal and may overhang another taxiway.
One of the most important aspects here is that too many people are trying to lay the blame too quickly. What has CRM taught any of us yet? Accidents and incidents should be used to learn. Find out what happened, then why, then develop means to avoid any recurrence.
As said earlier, no deaths or serious injuries, so wait for the facts to emerge before tying the noose.
The captain has ultimate responsibility for the safety of his aircraft and all persons onboard. (I am not here implying liability in this incident because none of us have the FULL facts).
If I am being marshalled onto stand and am worried about colliding with a ground obstruction, be it a vehicle or an incorrectly parked airbridge, should I blindly obey the instructions of the marshaller and wait for the bang. Then say "He told me to continue"?. NO. If you are in doubt, STOP and request assistance. How can you be sure the marshaller or controller can see what you feel may be a hazard?
Obviously in this incident, there was no marshaller. Likewise NO controller can have blame apportioned to them, because they are not responsible for separation on taxiways. They can request ground assistance if they foresee potential conflicts if, for example, an aircraft is pushed back farther than normal and may overhang another taxiway.
One of the most important aspects here is that too many people are trying to lay the blame too quickly. What has CRM taught any of us yet? Accidents and incidents should be used to learn. Find out what happened, then why, then develop means to avoid any recurrence.
As said earlier, no deaths or serious injuries, so wait for the facts to emerge before tying the noose.
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You are partly right. The only time a controller does not have any responsibility for separation on a taxiway or manouevering area, is when he or she can't see the aircraft, in which case the taxi clearance will have a clearance limit or a caution attached to it.
In any case, my point is not to apportion blame to a controller, rather to NOT apportion blame to a pilot.
Your marshalling example is spurious as well. A marshaller has little training and does not issue clearances. More to the point, if you are being marshalled onto stand, your protection is in the white lines to either side of you that ensure your clearance from fixed objects.
Now, if we are sitting in our 767, and a vehicle that we can't see drives into the way of the wingtip that we also can't see, and we hit it... how can you possibly lay the blame with the pilot, who was unable to see the problem? You can't stop and ask for assistance if you are unaware of the problem, and if the marshaller doesn't advise you.
In this case, marshallers are often held responsible in that they lose their jobs on the spot.
If you want to see an example of controllers ensuring separation, look no further than LVP's. That is a clear illustration of where responsibility lies when on the taxiway.
Sir George Cayley
At many airfields, aircraft are expected to hold in a "block", which has a single yellow line to signify the rear of the block. Holding in the block ensures your clearance. I don't know if Manchester uses these, but if not, they should.
I agree with the swiss cheese analogy, because if the 737 had been at the holding point, it wouldn't have happened... and if the controller had KNOWN that the 737 was holding a way back from the hold point (which is hard to understand), he or she would no doubt have passed a "caution the 737 holding" advisory... and so on and so forth.
In any case, my point is not to apportion blame to a controller, rather to NOT apportion blame to a pilot.
Your marshalling example is spurious as well. A marshaller has little training and does not issue clearances. More to the point, if you are being marshalled onto stand, your protection is in the white lines to either side of you that ensure your clearance from fixed objects.
Now, if we are sitting in our 767, and a vehicle that we can't see drives into the way of the wingtip that we also can't see, and we hit it... how can you possibly lay the blame with the pilot, who was unable to see the problem? You can't stop and ask for assistance if you are unaware of the problem, and if the marshaller doesn't advise you.
In this case, marshallers are often held responsible in that they lose their jobs on the spot.
If you want to see an example of controllers ensuring separation, look no further than LVP's. That is a clear illustration of where responsibility lies when on the taxiway.
Sir George Cayley
At many airfields, aircraft are expected to hold in a "block", which has a single yellow line to signify the rear of the block. Holding in the block ensures your clearance. I don't know if Manchester uses these, but if not, they should.
I agree with the swiss cheese analogy, because if the 737 had been at the holding point, it wouldn't have happened... and if the controller had KNOWN that the 737 was holding a way back from the hold point (which is hard to understand), he or she would no doubt have passed a "caution the 737 holding" advisory... and so on and so forth.
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I fail to understand why the baby 737 was holding at S2 when it had been cleared to hold at T1 for "some time". "Some time" seems to have been enough time to comply with the ATC instruction.
Holding a few metres short of the allocated point is one thing, but this was tens of metres.
-----------------------------------------
In general, unless the taxiway centerline ensures clearance from all aircraft types holding where instructed then this sort of incident will proliferate. The centerlines and holding point markings should serve to assure of adequate clearances provided that pilots use them as instructed in the Air Pilot or as instructed by ATC. Non-compliance equals negligence, does it not?
The "Heathrow Getout Anouncement" just is'nt good enough. It's becoming impossible to judge wingtip clearance from the cockpit on some types.
Holding a few metres short of the allocated point is one thing, but this was tens of metres.
-----------------------------------------
In general, unless the taxiway centerline ensures clearance from all aircraft types holding where instructed then this sort of incident will proliferate. The centerlines and holding point markings should serve to assure of adequate clearances provided that pilots use them as instructed in the Air Pilot or as instructed by ATC. Non-compliance equals negligence, does it not?
The "Heathrow Getout Anouncement" just is'nt good enough. It's becoming impossible to judge wingtip clearance from the cockpit on some types.
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Vd'I
Please provide the quote from the 'Air Pilot' or whatever that says exactly what you must do in order to hold "at" a particular point? And what is the prescribed distance from the Holding Point at which you must be?
If you actually read the AAIB report I gave a link to above, and even provided an extract from, the AAIB confirmed that (then anyway) they could find no reason why a pilot must go "right up" to a holding point - and supported a pilot who again was "10s of metres from his cleared point".
In short, there are countless possible reasons why the BMI aircraft did not move forward... and they should not result in a collision (risk).
You seem to be advocating the sort of people who, if they have a green light on the road, feel it is in your right to drive and deliberately hit the car that has intentionally or accidentally crossed the red light.
Fortunately, most drivers, and hopefully all professional pilots (maybe yourself excepted if you are one) allow for unforeseen events, and don't taxi with not a care in the world and expect ATC and procedures to cover you. I am not suggesting the 767 pilot(s) were doing this - there are countless possible explanations for why they ended up hitting the 737. The causes are determined by the AAIB... not here.
In general, unless the taxiway centerline ensures clearance from all aircraft types holding where instructed then this sort of incident will proliferate. The centerlines and holding point markings should serve to assure of adequate clearances provided that pilots use them as instructed in the Air Pilot or as instructed by ATC. Non-compliance equals negligence, does it not?
If you actually read the AAIB report I gave a link to above, and even provided an extract from, the AAIB confirmed that (then anyway) they could find no reason why a pilot must go "right up" to a holding point - and supported a pilot who again was "10s of metres from his cleared point".
In short, there are countless possible reasons why the BMI aircraft did not move forward... and they should not result in a collision (risk).
You seem to be advocating the sort of people who, if they have a green light on the road, feel it is in your right to drive and deliberately hit the car that has intentionally or accidentally crossed the red light.
Fortunately, most drivers, and hopefully all professional pilots (maybe yourself excepted if you are one) allow for unforeseen events, and don't taxi with not a care in the world and expect ATC and procedures to cover you. I am not suggesting the 767 pilot(s) were doing this - there are countless possible explanations for why they ended up hitting the 737. The causes are determined by the AAIB... not here.
Man. collision.
Despite some very sound posts on this subject, what the hell are we doing here, guys ?
What happened to the old adage of " no comment until we've heard the results of the inquiry,"
All we doing here is to feed the press with informed(?) analysis, good or bad, for which they would normally pay a fortune.
How about backing off until we know more ?
It was dark'ish. Crews were maybe tired / pi**ed off already, with a long night ahead (again). Delays.
There, but for the grace of God etc......... ?
Sleeve.
What happened to the old adage of " no comment until we've heard the results of the inquiry,"
All we doing here is to feed the press with informed(?) analysis, good or bad, for which they would normally pay a fortune.
How about backing off until we know more ?
It was dark'ish. Crews were maybe tired / pi**ed off already, with a long night ahead (again). Delays.
There, but for the grace of God etc......... ?
Sleeve.
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The captain has ultimate responsibility is often quoted. This is responsibility for decisions made from information and observations which he is reasonably expected to acquire from the machinery and environment.
Surely when a Clearance is issued, based on information which the captain does not have, responsibility is taken for the captain's actions. Any override would only be because of conflicting data.
An interesting situation arises when connected to a tug during pushback into a busy taxyway, especially when English is not the first language.
Surely when a Clearance is issued, based on information which the captain does not have, responsibility is taken for the captain's actions. Any override would only be because of conflicting data.
An interesting situation arises when connected to a tug during pushback into a busy taxyway, especially when English is not the first language.
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NigelOnDraft
The "Air Pilot" (guess you must be one of those old pilots!
) doesn't specify "exactly what you must do in order to hold "at" a particular point" because it doesn't need to. Some things in aviation, believe it or not, are assumed. If you are cleared to the holding point, the assumption is that any competent pilot will arrange his aircraft to be at, but not over, the prescribed point. This is what we call airmanship .
In the same way, it is assumed that when you receive a takeoff clearance, you don't taxi down the runway for a bit first, and then take off. This is because we are all taught to use all the available space, from an early point in our career. It is simple common sense.
The alternative is to legislate for ever possible aspect of aviation, which then opens the door for a very high level of scrutiny and subsequent penalties.
We all know that "hold at the holding point" means as close as you can reasonably get to the line without crossing it. Anyone who doesn't understand that, needs to go back to PPL school and start again.
What possible reason could there be for not pulling forward to the holding point (in general terms, not this specific case)?
The "Air Pilot" (guess you must be one of those old pilots!
) doesn't specify "exactly what you must do in order to hold "at" a particular point" because it doesn't need to. Some things in aviation, believe it or not, are assumed. If you are cleared to the holding point, the assumption is that any competent pilot will arrange his aircraft to be at, but not over, the prescribed point. This is what we call airmanship .In the same way, it is assumed that when you receive a takeoff clearance, you don't taxi down the runway for a bit first, and then take off. This is because we are all taught to use all the available space, from an early point in our career. It is simple common sense.
The alternative is to legislate for ever possible aspect of aviation, which then opens the door for a very high level of scrutiny and subsequent penalties.
We all know that "hold at the holding point" means as close as you can reasonably get to the line without crossing it. Anyone who doesn't understand that, needs to go back to PPL school and start again.
What possible reason could there be for not pulling forward to the holding point (in general terms, not this specific case)?
Just a numbered other
MOR
Well I, for one, rarely pull right up to the CAT1 holds for 27L at CDG, as having my hair parted by the wingtip of a landing big jet is even less appealing than having my tail removed by a taxiing aircraft.
Didn't ICAO get rid of blocks in favour of the system of holding points we now use?
I don't want to comment on this accident before the AAIB conclude their investigation. However I will say that if I taxi my jet into a stationary object, I will not be feeling too fireproof.
What possible reason could there be for not pulling forward to the holding point (in general terms, not this specific case)?
At many airfields, aircraft are expected to hold in a "block", which has a single yellow line to signify the rear of the block. Holding in the block ensures your clearance. I don't know if Manchester uses these, but if not, they should.
I don't want to comment on this accident before the AAIB conclude their investigation. However I will say that if I taxi my jet into a stationary object, I will not be feeling too fireproof.
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Assumptions?
The "Air Pilot" doesn't specify "exactly what you must do in order to hold "at" a particular point" because it doesn't need to. Some things in aviation, believe it or not, are assumed.
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Some things in aviation, believe it or not, are assumed.
But in most cases, any doubt in an instruction is queried and verified before being complied with by very cautious and suspicious pilots. What was it that makes an ‘Ass’ out of ‘u’ and ‘me’?
. . .you don't taxi down the runway for a bit first, and then take off
You do on 24L, the first 100m is not available as part of the take-off roll.
FWIW I’ve always disliked Boeing’s practice of putting the white nav lights on the wing tips, and not the tailcone, obscuring the extremities of the aeroplane in darkness and poor vis. I’ll never forget coming arse to face with the tail of a 757 in my little jet when it just loomed out of the murk. I’d like then to use all available lighting in poor conditions.
Look forward to several months of scribbling down ‘Pilots are to exercise caution when manoeuvring in the runway holding areas as wing tip clearance is not assured.’
But in most cases, any doubt in an instruction is queried and verified before being complied with by very cautious and suspicious pilots. What was it that makes an ‘Ass’ out of ‘u’ and ‘me’?
. . .you don't taxi down the runway for a bit first, and then take off
You do on 24L, the first 100m is not available as part of the take-off roll.
FWIW I’ve always disliked Boeing’s practice of putting the white nav lights on the wing tips, and not the tailcone, obscuring the extremities of the aeroplane in darkness and poor vis. I’ll never forget coming arse to face with the tail of a 757 in my little jet when it just loomed out of the murk. I’d like then to use all available lighting in poor conditions.
Look forward to several months of scribbling down ‘Pilots are to exercise caution when manoeuvring in the runway holding areas as wing tip clearance is not assured.’
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MOR
I wish you'd actually read the thread instead of making a pr*t of yourself:
1. You'll see the reference to Air Pilot was from a post by Val D'Isere - not me. I made it a quote for that reason - I don't know what it is either
2.
B*llocks. Read the thread. I have quoted from an AAIB report where another pilot held 10s of metres short of his clearance, justified it, and was supported by the AAIB who said they could find nothing to indicate why he should be right up to the Holding Point. He also had his tail clouted!
Plenty - can't be bothered to recite them all here - I've already quoted some above (the pilot referred to above) - but since you can't be bothered to read them up there, I doubt you'll be bothered to read my reply.
As an aside, at LHR, say crossing 27L from the V's I am very reluctant to go to the CAT 1 hold with landing traffic. It is just plain commonsense with 100s of tons of landing aeroplances under varying degrees of control due weather and maybe tech problems, not to try and park yourself right in the line of fire.
This is not the issue however. For some reason that is not really relevant, the 737 might have been cleared to T1, and might have been well short of it. Whatever, even if he was cleared to T1, and was at S2 (?), it does not mean he deserved having his tail hit... i.e. not being at T1 sounds maybe only a (minor) contributory factor. The major factors I'll leave to the AAIB to determine.
I wish you'd actually read the thread instead of making a pr*t of yourself:
1. You'll see the reference to Air Pilot was from a post by Val D'Isere - not me. I made it a quote for that reason - I don't know what it is either
2.
We all know that "hold at the holding point" means as close as you can reasonably get to the line without crossing it
What possible reason could there be for not pulling forward to the holding point (in general terms, not this specific case)?
As an aside, at LHR, say crossing 27L from the V's I am very reluctant to go to the CAT 1 hold with landing traffic. It is just plain commonsense with 100s of tons of landing aeroplances under varying degrees of control due weather and maybe tech problems, not to try and park yourself right in the line of fire.
This is not the issue however. For some reason that is not really relevant, the 737 might have been cleared to T1, and might have been well short of it. Whatever, even if he was cleared to T1, and was at S2 (?), it does not mean he deserved having his tail hit... i.e. not being at T1 sounds maybe only a (minor) contributory factor. The major factors I'll leave to the AAIB to determine.
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NigelOnDraft
I have read the thread, and you have missed the point (again).
No, there is no specific instruction as to exactly where to hold. Now, please show me the specific instruction in any CAA document that tells me what speed I must taxi at? Or perhaps you could show me where I am instructed by the CAA in the precise method of establishing the risk of a birdstrike?
The fact that not every single possible permutation of maouevering an aircraft is written down, does not absolve the pilot in command from using good judgement. To use the AIB report to try and justify holding a long way short of the holding point is simply doltish.
That is such a load of crap that it barely justifies a reply. However, if you feel that the published clearances are inadequate for you, feel free to make up your own. In fact, why not just stay at the pier, you should be safe there.
Has it never occurred to you that the holding point positions are arrived at after a very long risk assessment process? And that if somebody is far enough off track to hit you whilst you are sitting at the hold, it wouldn't really matter where you were on the taxiway system - you would still be at risk? An aircraft that out of control in the approach is going to end up a fireball, and a few metres back from the hold will almost certainly make no difference whatsoever.
Do please grow up.
Arkroyal
No, Edinburgh (for one) still uses them. Or did last time I was there.
I have read the thread, and you have missed the point (again).
No, there is no specific instruction as to exactly where to hold. Now, please show me the specific instruction in any CAA document that tells me what speed I must taxi at? Or perhaps you could show me where I am instructed by the CAA in the precise method of establishing the risk of a birdstrike?
The fact that not every single possible permutation of maouevering an aircraft is written down, does not absolve the pilot in command from using good judgement. To use the AIB report to try and justify holding a long way short of the holding point is simply doltish.
I am very reluctant to go to the CAT 1 hold with landing traffic. It is just plain commonsense with 100s of tons of landing aeroplances under varying degrees of control due weather and maybe tech problems, not to try and park yourself right in the line of fire.
Has it never occurred to you that the holding point positions are arrived at after a very long risk assessment process? And that if somebody is far enough off track to hit you whilst you are sitting at the hold, it wouldn't really matter where you were on the taxiway system - you would still be at risk? An aircraft that out of control in the approach is going to end up a fireball, and a few metres back from the hold will almost certainly make no difference whatsoever.
Do please grow up.
Arkroyal
Didn't ICAO get rid of blocks in favour of the system of holding points we now use?
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MOR
We'll have to disagree... I don't understand what you mean by:
- AAIB reports are investigations into incidents / accidents whose sole purpose is to "learn" and prevent future similar occurances. I for read them, and take note of that they say and don't. Whatever, I will believe them before you!
However, you are still again missing my point. Just because the 737 was (maybe) not where he was cleared to, does not consitute the sole or major cause of the incident i.e. not being at T1 does not give the 767 the right to taxi past regardless (not that I am saying he did). The old RAF adage "Don't Assume - Check" springs to mind...
We'll have to disagree... I don't understand what you mean by:
To use the AIB report to try and justify holding a long way short of the holding point is simply doltish.
However, you are still again missing my point. Just because the 737 was (maybe) not where he was cleared to, does not consitute the sole or major cause of the incident i.e. not being at T1 does not give the 767 the right to taxi past regardless (not that I am saying he did). The old RAF adage "Don't Assume - Check" springs to mind...
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Just because the 737 was (maybe) not where he was cleared to, does not consitute the sole or major cause of the incident i.e. not being at T1 does not give the 767 the right to taxi past regardless (not that I am saying he did). The old RAF adage "Don't Assume - Check" springs to mind...