Crash-Cork Airport
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sevenstrokeroll
Thank you for the excellent description of the systems. I think it will be interesting to see if a possible engine failure was involved here or not, though regardless of that, I have learnt something new today
What I was trying to work out was whether the prop could feather to the position in the photograph on its own (allowing the possibility of failure very shortly before the accident), or whether it could only have ended up there after the drills had been carried out (suggesting it may have happened earlier on in the approach or previous hold).
Obviously this is all total guesswork on my part (and also assuming that the position of the prop is not just a result of the accident itself), but just a thought that had occurred to me...
Thank you for the excellent description of the systems. I think it will be interesting to see if a possible engine failure was involved here or not, though regardless of that, I have learnt something new today
What I was trying to work out was whether the prop could feather to the position in the photograph on its own (allowing the possibility of failure very shortly before the accident), or whether it could only have ended up there after the drills had been carried out (suggesting it may have happened earlier on in the approach or previous hold).
Obviously this is all total guesswork on my part (and also assuming that the position of the prop is not just a result of the accident itself), but just a thought that had occurred to me...
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Even if the apparently feathered position of the port prop blades is due to loss of oil pressure, the damage to the blades would indicate that there was little or no rotation on impact, whereas the stbd prop blades appear to be sheared off
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LAI
yes, I was thinking that sort of thing too.
my working theory though is this...normal approach to another go around and due to some reason an engine failed and the plane got too slow and rolled inverted.
fuel?
fuel starvation due to the above crossflow thing ( the fuel valve could be found open as I recall as electrical failure opens the valve...but folks its been awhile and I can't remember)
sucking a bird
flameout due to moisture runback if prop spinner de/anti ice selected on with large amount of ice on the spinner
so many things
I am surprised that this type has CVR and DFDR, but if they do have these boxes, we should know soon.
yes, I was thinking that sort of thing too.
my working theory though is this...normal approach to another go around and due to some reason an engine failed and the plane got too slow and rolled inverted.
fuel?
fuel starvation due to the above crossflow thing ( the fuel valve could be found open as I recall as electrical failure opens the valve...but folks its been awhile and I can't remember)
sucking a bird
flameout due to moisture runback if prop spinner de/anti ice selected on with large amount of ice on the spinner
so many things
I am surprised that this type has CVR and DFDR, but if they do have these boxes, we should know soon.
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The accident investigation team has just stated on RTE TV News that the aircraft skidded along the RWY for about 190 yds and that the stbd wing hit the surface before the aircraft rolled inverted
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Yes, your theory does sound plausible, and is pretty much what I was thinking as well.
edit: Or maybe not!
As you say, the fact that there is apparently a CVR and FDR will hopefully reveal all.
edit: Or maybe not!
As you say, the fact that there is apparently a CVR and FDR will hopefully reveal all.
Last edited by LAI; 11th Feb 2011 at 20:43. Reason: Just seen IslandPilot's post...
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with the most recent post of island pilot
I now think the plane was over corrected in poor visibility, dragging the right wing until it flipped over
engine failure is less likely a scenario with the post indicating the wing was dragging.
it is so easy to lose visual reference and over correct in low vis.
I now think the plane was over corrected in poor visibility, dragging the right wing until it flipped over
engine failure is less likely a scenario with the post indicating the wing was dragging.
it is so easy to lose visual reference and over correct in low vis.
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NTS 331
Having spent many years building the 331 I thought I would give you fly boys some hard facts about the NTS system
The NTS system is purely a drag reduction system, it will not auto-feather. On an engine failure or flame-out the prop will now drive the engine. This is sensed by the NTS (negative torque, the clue is in the name) system and it will dump oil pressure out of the prop and it will start to move toward feather. However, once the prop moves toward feather it is now no longer driving the engine so the negative torque is no longer sensed and the whole system resets and the prop moves away from feather in an attempt return to the speed currently set on the prop governor, for landing 100% (remember it was never feathered anyway). If auto ignition is fitted it would be triggered by the NTS system and hopefully relight the engine. If auto ignition is not fitted or does not succeed the engine will remain in the NTS mode until a manual feather is carried out by the crew. As has been mentioned, the prop must be placed onto the start locks during normal shutdown. If this is not done the prop will slowly creep toward the feather position due to internal leakages, so in the case of this accident, even if both engines were running at the time of the crash, both props will feather once stationary (internal damage excluded) Obviously, none of this would be the happen in the case of a catastrophic failure of the engine, prop or gearbox
The NTS system is purely a drag reduction system, it will not auto-feather. On an engine failure or flame-out the prop will now drive the engine. This is sensed by the NTS (negative torque, the clue is in the name) system and it will dump oil pressure out of the prop and it will start to move toward feather. However, once the prop moves toward feather it is now no longer driving the engine so the negative torque is no longer sensed and the whole system resets and the prop moves away from feather in an attempt return to the speed currently set on the prop governor, for landing 100% (remember it was never feathered anyway). If auto ignition is fitted it would be triggered by the NTS system and hopefully relight the engine. If auto ignition is not fitted or does not succeed the engine will remain in the NTS mode until a manual feather is carried out by the crew. As has been mentioned, the prop must be placed onto the start locks during normal shutdown. If this is not done the prop will slowly creep toward the feather position due to internal leakages, so in the case of this accident, even if both engines were running at the time of the crash, both props will feather once stationary (internal damage excluded) Obviously, none of this would be the happen in the case of a catastrophic failure of the engine, prop or gearbox
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Thanks for that Templer, good to have a proper description of the TPE 331 system from the "horses mouth". While this could explain the apparent feathered position of the port prop in the photo in Post 267, do you think that the prop was rotating under power at impact?
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Unless the engine has seized or the gearbox failed it will remain in an NTS condition until feathered. The NTS system is only temporary until the crew manually feather the prop. Although it is a "drag reduction system" there is still plenty of drag you would want to get rid of ASAP, so if no auto relight or air start possible then the crew will feather it soon rather than later. As for picture in 267, 2 blades are clearly bent, maybe that would indicate some rotation but as for spectulating, that is up to the crash pro's, not me
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Quote:
That said, listening to a mate who returned into Blackpool in a J31 on Monday at 30 degrees of yaw, you do wonder. that said, they got them down, but how differently that could have turned out one begins to wonder on the back of this.
What rubbish. Have you any idea what the crosswind limit is on a J31? I fly a turboprop not that much bigger than a J31 and the crossind limit is 35 knots. Have you ever seen a crabbed approach in that kind of wind? What utter and utter bull*it some people come out with on these forums. Stick to your bloody armchairs for gods sake.
- he has literally tens of thousands of pax hours. If he felt compelled to comment on it, as he saw it, then I tend to listen.
That said, listening to a mate who returned into Blackpool in a J31 on Monday at 30 degrees of yaw, you do wonder. that said, they got them down, but how differently that could have turned out one begins to wonder on the back of this.
What rubbish. Have you any idea what the crosswind limit is on a J31? I fly a turboprop not that much bigger than a J31 and the crossind limit is 35 knots. Have you ever seen a crabbed approach in that kind of wind? What utter and utter bull*it some people come out with on these forums. Stick to your bloody armchairs for gods sake.
- he has literally tens of thousands of pax hours. If he felt compelled to comment on it, as he saw it, then I tend to listen.
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metroliner and wing draging
to look at a metro 4 or 3 for that matter, one sees the wing
but looking at a Metro 2 or 2a you see a much shorter wing. the spar runs tip to tip.
the wing on the 4 or 3 is extended...but does not run the spar all the way to the tip...its just sort of bolted on without a spar carry through. so it might easily collapse if draged and perhaps allows the plane to flip over?
take a look some time...the ailerons tell the whole story...almost all the way to the tip on the earlier metros, and stops where the wing extension starts on the latter more powerful metroliners
to look at a metro 4 or 3 for that matter, one sees the wing
but looking at a Metro 2 or 2a you see a much shorter wing. the spar runs tip to tip.
the wing on the 4 or 3 is extended...but does not run the spar all the way to the tip...its just sort of bolted on without a spar carry through. so it might easily collapse if draged and perhaps allows the plane to flip over?
take a look some time...the ailerons tell the whole story...almost all the way to the tip on the earlier metros, and stops where the wing extension starts on the latter more powerful metroliners
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IslandPilot
Your reference to the Ariana accident at Gatwick, ....good call. Essential reading for any pilot who operates down to 'minimums' for a living.
As a 150hr PPL, I managed to read the report the month it was published.
Much of it I couldn't understand at the time, but on re-reading it sometime later, I was able to take on board a number of lessons that could be gleaned from it. These I carried with me through my next 15K hours and in to retirement.
I think sometime after this accident 'state minimum RVR's' were introduced in the U.K.
As a 150hr PPL, I managed to read the report the month it was published.
Much of it I couldn't understand at the time, but on re-reading it sometime later, I was able to take on board a number of lessons that could be gleaned from it. These I carried with me through my next 15K hours and in to retirement.
I think sometime after this accident 'state minimum RVR's' were introduced in the U.K.
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Additional information from TV News reports
Time someone mentioned a few things that appear to have been lost in the verbal fog
From today's RTE news coverage, there are several factors that I suspect will be significant to the eventual report outcome.
When the remains of the aircraft were being lifted for removal, a number of relevant things became clearer.
There is no apparent damage to the landing gear, the mains are pretty much where they should be, and there is no apparent tyre damage, or contamination with mud or grass.
There is significant displacement of the nose gear towards the starboard side, but I get the impression that this has been caused by significant structural distortion of the fusleage remains, the nose gear leg does not appear to be bent, and again, there is no evidence of contamination on the tyres.
Having said that, given that there was a post crash fire, it's possible that the water and foam used to extinguish the blaze may have washed any contamination off.
In terms of the possible cause of the inversion, it was very clear from pictures on the news report that the outboard starboard wing section has detached from the aircraft a few feet from the engine. It is not clear from the pictures if that section was torn off by impact damage, or if it failed for some other reason. It (for me) certainly explains why the aircraft became inverted.
The port engine is displaced from the thrust line in an upward direction, which gives an indication of the speed of the rotation.The damage to the blades that is visible in the picture posted above suggests that they were turning at a significant speed on impact, and that they were close to the feather position when ground contact was made, by virtue of the shape of the deformation.
There have been no suggestions of a reason for this. It was not possible to see any details of the propellor on the starboard engine.
No information has yet been given of the fuel uplift prior to this flight. The media in Ireland have reported that the expected alternate of Shannon also had poor conditions at the time of arrival at Cork, but no details have been given, and no aviation sources have confirmed this.
This evening's News report (Link below) added information that the aircraft had made ground contact on the runway, but the AAIB were at pains to make it clear that while they have a "reasonable understanding" of the sequence of events, they are not prepared to comment further until they have the data from the FDR.
No mention has been made of the experience levels of the crew, but it has been stated that the First Officer had only been working with "Manx2" for 2 weeks.
There is also a comment that has not been qualified that the aircraft has only just returned from a maintenance inspection in Spain, The implication was that the inspection was a major inspection.
The video reports that gives some of these views can at present be found at Cork Airport to resume full service tomorrow - RTÉ News
I do not know how long this link will remain valid, or know if it can be accessed from all locations.
Another piece of related news is that the Deputy First Minister of the North, Martin McGuinness, had been booked to travel on the flight, but cancelled his trip shortly before departure.
All in all, some of the factors revealed in these snippets appears contradictory. If the port engine had for some reason failed, that would be more likely to produce a wing low scenario on the port side, but the aircraft has rolled starboard.
Whatever the final report conclusions are, this has been a sad event that has caused much pain to many people. There are still 4 people in Cork Hospital with serious injuries, although they are said to be "stable".
From today's RTE news coverage, there are several factors that I suspect will be significant to the eventual report outcome.
When the remains of the aircraft were being lifted for removal, a number of relevant things became clearer.
There is no apparent damage to the landing gear, the mains are pretty much where they should be, and there is no apparent tyre damage, or contamination with mud or grass.
There is significant displacement of the nose gear towards the starboard side, but I get the impression that this has been caused by significant structural distortion of the fusleage remains, the nose gear leg does not appear to be bent, and again, there is no evidence of contamination on the tyres.
Having said that, given that there was a post crash fire, it's possible that the water and foam used to extinguish the blaze may have washed any contamination off.
In terms of the possible cause of the inversion, it was very clear from pictures on the news report that the outboard starboard wing section has detached from the aircraft a few feet from the engine. It is not clear from the pictures if that section was torn off by impact damage, or if it failed for some other reason. It (for me) certainly explains why the aircraft became inverted.
The port engine is displaced from the thrust line in an upward direction, which gives an indication of the speed of the rotation.The damage to the blades that is visible in the picture posted above suggests that they were turning at a significant speed on impact, and that they were close to the feather position when ground contact was made, by virtue of the shape of the deformation.
There have been no suggestions of a reason for this. It was not possible to see any details of the propellor on the starboard engine.
No information has yet been given of the fuel uplift prior to this flight. The media in Ireland have reported that the expected alternate of Shannon also had poor conditions at the time of arrival at Cork, but no details have been given, and no aviation sources have confirmed this.
This evening's News report (Link below) added information that the aircraft had made ground contact on the runway, but the AAIB were at pains to make it clear that while they have a "reasonable understanding" of the sequence of events, they are not prepared to comment further until they have the data from the FDR.
No mention has been made of the experience levels of the crew, but it has been stated that the First Officer had only been working with "Manx2" for 2 weeks.
There is also a comment that has not been qualified that the aircraft has only just returned from a maintenance inspection in Spain, The implication was that the inspection was a major inspection.
The video reports that gives some of these views can at present be found at Cork Airport to resume full service tomorrow - RTÉ News
I do not know how long this link will remain valid, or know if it can be accessed from all locations.
Another piece of related news is that the Deputy First Minister of the North, Martin McGuinness, had been booked to travel on the flight, but cancelled his trip shortly before departure.
All in all, some of the factors revealed in these snippets appears contradictory. If the port engine had for some reason failed, that would be more likely to produce a wing low scenario on the port side, but the aircraft has rolled starboard.
Whatever the final report conclusions are, this has been a sad event that has caused much pain to many people. There are still 4 people in Cork Hospital with serious injuries, although they are said to be "stable".
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Propeller Damage
Irish Steve, sorry but disagree with you conclusions on the prop damage and also a answer to Island Pilots question.
The port propeller is in the feathered position. This could have been feathered by the crew because the engine had stopped producing power.
However, the manufacturer has previously reported instances of the blades moving out of course pitch during impact, particularly where the airframe is still in forward motion with respect to the angle of the propeller blades. This is not uncommon on this type of propeller system.
However, the one port propeller blade is in almost perfect condition indicating little to no rotational speed of the propeller hub upon impact with the ground, with little or no torque applied, consistent with a feathered prop due to the engine not producing power before contact with the ground. All port propeller blades appear to be in the fully feathered position consistent with intentional manipulation of the controls to the stop/feather position of the controls rather than a partial feathered position caused by the impact as seen in some previous incidents.
The post incident shape of the other two port propellers is consistent with impact and post impact dynamics. The dynamics would be a combination of vertical impact force due to the weight of the aircraft and kinetic energy of the rolling motion, with very little forward momentum of the airframe, combined with some kinetic energy from the excursion from the runway, producing lateral movement (form to left to right) of the airframe while coming to rest in it's final inverted position, rather than rotational speed and or torque applied to the hub. Notice that the bend in the propellers is in an anticlockwise direction. Again consistent with the lateral movement of an inverted airframe from left to right.
Propeller contact with the ground with an engine producing high power will normally result in a catastrophic failure of the hub. This will normally cause the propellers to depart from the hub at high velocity. You can see typical evidence of this on the incident aircrafts Starboard propeller hub. i.e. No propeller and visible signs of damage to the prop spinner.
The most likely conclusion from the above, based upon visible evidence from the combination of pictures and AAIB statement to date, is that the port engine had stopped producing power pre impact and stop/feathering action had most likely been initiated by the crew, while the starboard engine was producing high power upon impact.
The port propeller is in the feathered position. This could have been feathered by the crew because the engine had stopped producing power.
However, the manufacturer has previously reported instances of the blades moving out of course pitch during impact, particularly where the airframe is still in forward motion with respect to the angle of the propeller blades. This is not uncommon on this type of propeller system.
However, the one port propeller blade is in almost perfect condition indicating little to no rotational speed of the propeller hub upon impact with the ground, with little or no torque applied, consistent with a feathered prop due to the engine not producing power before contact with the ground. All port propeller blades appear to be in the fully feathered position consistent with intentional manipulation of the controls to the stop/feather position of the controls rather than a partial feathered position caused by the impact as seen in some previous incidents.
The post incident shape of the other two port propellers is consistent with impact and post impact dynamics. The dynamics would be a combination of vertical impact force due to the weight of the aircraft and kinetic energy of the rolling motion, with very little forward momentum of the airframe, combined with some kinetic energy from the excursion from the runway, producing lateral movement (form to left to right) of the airframe while coming to rest in it's final inverted position, rather than rotational speed and or torque applied to the hub. Notice that the bend in the propellers is in an anticlockwise direction. Again consistent with the lateral movement of an inverted airframe from left to right.
Propeller contact with the ground with an engine producing high power will normally result in a catastrophic failure of the hub. This will normally cause the propellers to depart from the hub at high velocity. You can see typical evidence of this on the incident aircrafts Starboard propeller hub. i.e. No propeller and visible signs of damage to the prop spinner.
The most likely conclusion from the above, based upon visible evidence from the combination of pictures and AAIB statement to date, is that the port engine had stopped producing power pre impact and stop/feathering action had most likely been initiated by the crew, while the starboard engine was producing high power upon impact.
Last edited by theavionicsbloke; 11th Feb 2011 at 23:05. Reason: correct typo
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Cork
All,
There is a golden rule: 2 approaches max then divert. Ignore this at your cost.
Sensible decisions at the planning stage in the crew room must always ensure at least one workable alternate airfield. If you can't find one, don't leave the ground. Always look at your planning minima for diversions. If the alternate airfield can provide a CAT 1 ILS, only use it if the weather on the day would ensure a successful approach if you could only use a non precision aid for its expected runway in use. This is just the most simple and basic of planning considerations and if you don't understand this you should not be flying and you are plainly not a professional or even just a competent PPL.
There is a golden rule: 2 approaches max then divert. Ignore this at your cost.
Sensible decisions at the planning stage in the crew room must always ensure at least one workable alternate airfield. If you can't find one, don't leave the ground. Always look at your planning minima for diversions. If the alternate airfield can provide a CAT 1 ILS, only use it if the weather on the day would ensure a successful approach if you could only use a non precision aid for its expected runway in use. This is just the most simple and basic of planning considerations and if you don't understand this you should not be flying and you are plainly not a professional or even just a competent PPL.
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Irish Pilot1990
You make a very good point. Rarely is it one single cause.
I know this was this F/O's 2nd week in his current post, but was this also he's 1st job commercial pilot post? I see he was out of Cabair.
Difficult situation if he was an in experienced F/O, He apparantly was rostered on this flight at the last minute, so possibly, new route, new aircraft type etc. Only takes a Captain having a bad day, bad wx, A N other problem and bingo!
You make a very good point. Rarely is it one single cause.
I know this was this F/O's 2nd week in his current post, but was this also he's 1st job commercial pilot post? I see he was out of Cabair.
Difficult situation if he was an in experienced F/O, He apparantly was rostered on this flight at the last minute, so possibly, new route, new aircraft type etc. Only takes a Captain having a bad day, bad wx, A N other problem and bingo!
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Delays don't come into this, it is always safety first, take your time, we are professionals.
Setting up for different runways, come on, Cork only has two and again we are professionals.
Missed approaches, honestly if you are unprepared for one you should give up your seat as you are a danger. Any approach could become a baulked landing / missed approach. Don't just brief for the approach, brief for the missed approach and further to that say how you will achieve it and build a mental model so that you can do it from recall. A competent crew will come up with a plan before the event about what they will do when they have flown the missed approach.
If a Captain knows that he is to operate with a low hour or new to type F.O. he must take that into consideration and factor that into how the flight will be conducted.
As regards fuel pressures can I draw your attention to safe flight planning.
Again as regards alternates and weather its only a lack of planning that will get you into trouble.
Setting up for different runways, come on, Cork only has two and again we are professionals.
Missed approaches, honestly if you are unprepared for one you should give up your seat as you are a danger. Any approach could become a baulked landing / missed approach. Don't just brief for the approach, brief for the missed approach and further to that say how you will achieve it and build a mental model so that you can do it from recall. A competent crew will come up with a plan before the event about what they will do when they have flown the missed approach.
If a Captain knows that he is to operate with a low hour or new to type F.O. he must take that into consideration and factor that into how the flight will be conducted.
As regards fuel pressures can I draw your attention to safe flight planning.
Again as regards alternates and weather its only a lack of planning that will get you into trouble.
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FOs mother spoke today of how her son had only just graduated so we can take it this was his first commercial job. Also she said on hearing of the accident she still held a glimmer of hope as her son was expecting to do a royal mail flight and must have been changed at late notice...yet another hole in the swiss cheese.
Also am I missing something with regards to saying it is bad practice, but legal, to shoot more then 2 approaches
If you have enough fuel to stay whats wrong with shooting as many approaches as you can till you hit the legal minimum of fuel needed for diversion/holiding/reserves, if alternate wx is good that is.
Also am I missing something with regards to saying it is bad practice, but legal, to shoot more then 2 approaches
If you have enough fuel to stay whats wrong with shooting as many approaches as you can till you hit the legal minimum of fuel needed for diversion/holiding/reserves, if alternate wx is good that is.
Last edited by irishpilot1990; 12th Feb 2011 at 00:40.