Delta B767 in multiple bird strike
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Surely we should be asking why so much engine damage was done by an encounter with a flock of birds. Flocks of gulls are not uncommon.
And the more curious of us will ask what the results of the engine bird ingestion certification tests looked like, and whether they match current knowledge of the bird threat.
And the more curious of us will ask what the results of the engine bird ingestion certification tests looked like, and whether they match current knowledge of the bird threat.
And please feel free to correct me if I am wrong - not the first time, won't be the last....
The test is not for whether the engine will survive an encounter with a bird and keep on ticking in one piece, but whether, upon encountering said bird, there is an uncontained blade failure or not.
The last thing you want is ruptured fuel tanks with bits of (hot) engine sticking out of them or ruptured SLF with bits of (hot) engine sticking out of them.
PanmaN
Last edited by Panman; 11th Jul 2007 at 03:01. Reason: formatting
The test requirements for flocking bird encounters is performance based and requires that the engine be able to provide enough power to safely land the aircraft.
You can pretty much make a shambles of the fan (scrap every blade) and still make enough power to safely land.
the key is the fan blade tip clearance and what happens to that
The certification requirements have increased since the engines powering the B767 were designed.
Still there has to be a degree of avoidance coupled with even today's stronger engines else you can break anything that man makes, including the aircraft. With the latest generation engines the aircraft is the weakest link in a large bird encounter once in the air.
You can pretty much make a shambles of the fan (scrap every blade) and still make enough power to safely land.
the key is the fan blade tip clearance and what happens to that
The certification requirements have increased since the engines powering the B767 were designed.
Still there has to be a degree of avoidance coupled with even today's stronger engines else you can break anything that man makes, including the aircraft. With the latest generation engines the aircraft is the weakest link in a large bird encounter once in the air.
XetroV:
Where was that disaster with the C-130?
In the 1970s a Lockheed Electra with passengers crashed into Boston Harbor after hitting a flock of starlings. Nobody survived.
A Republic Airlines (or North Central) Convair 580 many years ago in the upper midwest hit a duck or a goose. The Captain was hurt, lost the vision in one eye but was able to demonstrate some sort of depth perception in the simulator etc and went back to flying.
We have never trained for bird strikes.
For years, the experts believed that using radar would induce birds to avoid airplanes, but they found out after better research that there were no noticeable benefits.
But maybe a slow-flying Mig 25 Foxbat's radar might give birds some incentive to steer away.
Where was that disaster with the C-130?
In the 1970s a Lockheed Electra with passengers crashed into Boston Harbor after hitting a flock of starlings. Nobody survived.
A Republic Airlines (or North Central) Convair 580 many years ago in the upper midwest hit a duck or a goose. The Captain was hurt, lost the vision in one eye but was able to demonstrate some sort of depth perception in the simulator etc and went back to flying.
We have never trained for bird strikes.
For years, the experts believed that using radar would induce birds to avoid airplanes, but they found out after better research that there were no noticeable benefits.
But maybe a slow-flying Mig 25 Foxbat's radar might give birds some incentive to steer away.
From an airport point of view, the problem in this case is that the gulls were there, or, if that was unavoidable, that the crew was not warned.
It is NOT impossible to have a system of alerting crews, via ATC, of flocks that might affect a departing aircraft. It IS expensive because it requires people on the ground, in all operating hours in daylight. One day, radar may be good enough, but even that will not spot a flock on the ground which can fly up into the climb-out path after an aircraft is committed to take off.
As some posters have pointed out, loss of take-off power on both sides, or full loss on one side and partial on the other, is not regularly practised in the normal training cycle.
Unfortunately it is a matter of sheer luck, assisted perhaps by avoiding action if that is possible (unlikely), for a multiple bird strike to be on one side only. The probability, it seems to me, is that it will be on both sides if and when it happens.
At airports where there is a significant risk of multiple bird strikes in spite of all the active and passive control measures that are taken, which probably includes most within 10 miles of an estuary, large body of water, rubbish dump or coastline, there can and should be much, much better systems in place to monitor the presence of flocks, airborne or on the ground, within 500m (say) of the departure runway c/l from the start of roll for, say, 4,000m. (That's my very rough guess at the distance needed to gain enough height to (a) take proper recovery action) and (b) be above the usual maximum height at which birds are found.)
Crews can be warned via ATC of the presence of a flock, with the take-off clearance if necessary, and take the decision to delay rolling or go. (ATC sholuld apply no pressure at this point apart, maybe, from withholding the clearance in the first place.)
Rather than bewailing the fact that engines are vulnerable to multiple bird strikes, we should accept that they are (is a frozen chicken still the only test? Didn't a swarm of bees recently do some damage to an ancient B737-200?) and work on preventing multiple strikes. It is perfectly possible to do that, as long as airports have the will and the money to do so.
In the case of FCO, it would be interesting to learn whether or not there are good systems in place to prevent and/or warn crews about flocks. If there are, the evidence suggests that they don't work.
PS
BTW, I thought that the last civil aircraft built with no containment ring was the Shorts Skyvan (and possibly its derivatives?), which experienced a number of uncontained turbine disintegrations until the TPE 331 FCU was modified to prevent runaway turbine overspeeds when the gearbox drive failed, as it sometimes did.
In two cases at least in the 1970's, bits penetrated the fuel tank (in the cabin roof), and cabin, narrowly missing the quite startled passengers, who thought that simply being a Skyvan passenger was bad enough already without bombardment by shrapnel and having fuel poured all over them to enhance their customer experience.
It is NOT impossible to have a system of alerting crews, via ATC, of flocks that might affect a departing aircraft. It IS expensive because it requires people on the ground, in all operating hours in daylight. One day, radar may be good enough, but even that will not spot a flock on the ground which can fly up into the climb-out path after an aircraft is committed to take off.
As some posters have pointed out, loss of take-off power on both sides, or full loss on one side and partial on the other, is not regularly practised in the normal training cycle.
Unfortunately it is a matter of sheer luck, assisted perhaps by avoiding action if that is possible (unlikely), for a multiple bird strike to be on one side only. The probability, it seems to me, is that it will be on both sides if and when it happens.
At airports where there is a significant risk of multiple bird strikes in spite of all the active and passive control measures that are taken, which probably includes most within 10 miles of an estuary, large body of water, rubbish dump or coastline, there can and should be much, much better systems in place to monitor the presence of flocks, airborne or on the ground, within 500m (say) of the departure runway c/l from the start of roll for, say, 4,000m. (That's my very rough guess at the distance needed to gain enough height to (a) take proper recovery action) and (b) be above the usual maximum height at which birds are found.)
Crews can be warned via ATC of the presence of a flock, with the take-off clearance if necessary, and take the decision to delay rolling or go. (ATC sholuld apply no pressure at this point apart, maybe, from withholding the clearance in the first place.)
Rather than bewailing the fact that engines are vulnerable to multiple bird strikes, we should accept that they are (is a frozen chicken still the only test? Didn't a swarm of bees recently do some damage to an ancient B737-200?) and work on preventing multiple strikes. It is perfectly possible to do that, as long as airports have the will and the money to do so.
In the case of FCO, it would be interesting to learn whether or not there are good systems in place to prevent and/or warn crews about flocks. If there are, the evidence suggests that they don't work.
PS
BTW, I thought that the last civil aircraft built with no containment ring was the Shorts Skyvan (and possibly its derivatives?), which experienced a number of uncontained turbine disintegrations until the TPE 331 FCU was modified to prevent runaway turbine overspeeds when the gearbox drive failed, as it sometimes did.
In two cases at least in the 1970's, bits penetrated the fuel tank (in the cabin roof), and cabin, narrowly missing the quite startled passengers, who thought that simply being a Skyvan passenger was bad enough already without bombardment by shrapnel and having fuel poured all over them to enhance their customer experience.
Last edited by old,not bold; 11th Jul 2007 at 09:16.
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here's a clip from the hollywood film 'the edge' , here's what happens when canadian geese hit your engine.......
http://www.maximonline.com/slideshow...es.aspx?film=6
http://www.maximonline.com/slideshow...es.aspx?film=6
Not available in stores.
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Where was that disaster with the C-130?
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Slinks.
The point I was making is that you are now paying a LOT less for most flights than a few years ago, while aircrew salaries are driven down partly because of that.
The point I was making is that you are now paying a LOT less for most flights than a few years ago, while aircrew salaries are driven down partly because of that.
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Reminds me of the video on flightlevel350.com of a Thomson Airline taking off with right engine failure due to a bird being ingested at the point of rotation. The situation was handled quite well then and this one too.
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No no no . Not the same thing at all. A single engine failure should be a minor event, even with an increase in crew workload.
A double engine failure on a twin could be catastrophic, hence the interest in this event.
A double engine failure on a twin could be catastrophic, hence the interest in this event.
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Originally Posted by CAAAD
No no no . Not the same thing at all. A single engine failure should be a minor event, even with an increase in crew workload.
An engine failure is NEVER a "minor event". And yes, until you've established, as well as you can, that there is still an engine on the pylon, that you're not trailing a sheet of flame a hundred feet long, and that there are no dead and injured in the cabin from an uncontained turbine disc failure going walkabout.... yes.... you could say there's an "increase in crew workload".
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Nigel...you are 100% correct...the sim is for realistic scenarios, not the double (or triple in my case) engine failure shortly after TO. However, I have had instructors load me up with so many inprobable failures (multiple engine failures, system A and B inop, loss of pressurization and cabin fire, etc) that the only option is being the first at the scene of the accident...when that happens I welcome it because it's always in the last 30 minutes of the recurrent, and when things go that bad, I know I've all ready requalified for another 6 months....again....
Slinks...thanks for your insight, I agree, a job well done that most of us will never encounter in our careers...It has happened before, however with a tragic outcome...Eastern lost an Electra at Boston due to ingestion of starlings in 3 of the 4 engines...having said that, does anyone ever think you're flying a revenue trip today where any emergency could happen, then tomorrow you go to the sim for your 6 month and they give you a few "practice" trys before the eval?
What if it happened the day before?...
That Delta crew didn't get a "practice" before taking off from Rome, and on July 23rd, I hope they don't need on when they take me from Moscow to Atlanta....
Slinks...thanks for your insight, I agree, a job well done that most of us will never encounter in our careers...It has happened before, however with a tragic outcome...Eastern lost an Electra at Boston due to ingestion of starlings in 3 of the 4 engines...having said that, does anyone ever think you're flying a revenue trip today where any emergency could happen, then tomorrow you go to the sim for your 6 month and they give you a few "practice" trys before the eval?
What if it happened the day before?...
That Delta crew didn't get a "practice" before taking off from Rome, and on July 23rd, I hope they don't need on when they take me from Moscow to Atlanta....
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Had a pleasant introduction into the double engine failure last time round in the sim.
One shut down for a flame out at V1, single eng approach to go round, and on the miss, engine compressor stalling/surging/over temping on the live engine.
Quickest circuit I've seen on the 777, and a quick relight by recall on the original failure giving stable thrust at 300' on approach.
Wouldn't have liked to see it for real, certainly an eye opener in the sim!
One shut down for a flame out at V1, single eng approach to go round, and on the miss, engine compressor stalling/surging/over temping on the live engine.
Quickest circuit I've seen on the 777, and a quick relight by recall on the original failure giving stable thrust at 300' on approach.
Wouldn't have liked to see it for real, certainly an eye opener in the sim!
If you have a close look at the images of the American 767 that Kingair9 linked to, one of them shows how far into the flight deck there was penetration on the Captain's side. A higher speed and a bigger bird could have possibly restricted the control column. While the controls can be split, with enough interference it might not matter whether you still had power or not.
I am a believer in reducing the odds by doing 250 KIAS or less below 10,000, especialy in active bird areas.
I am a believer in reducing the odds by doing 250 KIAS or less below 10,000, especialy in active bird areas.
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Rather closer to the Engineering coalface than you, mon ami.
I repeat - aircraft safety assessments consider a single engine failure resulting in only loss of power as a minor event. Obviously.
I repeat - aircraft safety assessments consider a single engine failure resulting in only loss of power as a minor event. Obviously.
[quote] Rather closer to the Engineering coalface than you, mon ami.
I repeat - aircraft safety assessments consider a single engine failure resulting in only loss of power as a minor event. [quote]
agree
all within the trainedl pilot workload
I repeat - aircraft safety assessments consider a single engine failure resulting in only loss of power as a minor event. [quote]
agree
all within the trainedl pilot workload
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And there was the infamous EAL L-1011 triple engine failure due to inporperly assembled "O" rings fitted during a routine maint check...they were preparing to ditch just short of MIA when they got the first one they shut down re-lit to barely make it across the airport boundry...
This was a training flight with the LHS Captain doing OE with the Training Capt in the RHS...(1983 I believe)
This was a training flight with the LHS Captain doing OE with the Training Capt in the RHS...(1983 I believe)
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Justo some rumors I heard from Alitalia maintenance crew, wich had to replace the engines on the affected aircraft.
- As mentioned many blades were damaged on both engine.
- One engine had to be shut down at some point, the other one, was only able to give partial power
- crew started to dump fuel, but with both engines damaged they decided to come back immediately, with a 10 tons overweight landing.
- Due to the excess of braking required due to the higher weight/speeds but also as they were not able to use reverse most of the main landing gear tyres blew up...
hope can help the discussion...
- As mentioned many blades were damaged on both engine.
- One engine had to be shut down at some point, the other one, was only able to give partial power
- crew started to dump fuel, but with both engines damaged they decided to come back immediately, with a 10 tons overweight landing.
- Due to the excess of braking required due to the higher weight/speeds but also as they were not able to use reverse most of the main landing gear tyres blew up...
hope can help the discussion...
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Tire Fuse Plugs
loveGSM,
Is it possible that the tires did not "blow up?"
The link below is a brief summary of tire fuse plugs, which this 767 has. The design is intended to prevent tires from "blowing up." However, I was not there, and I did not speak with the Alitalia maintenance crew as you did.
http://www.freepatentsonline.com/4535957.html
A device (10) for venting aircraft tires comprises a fusible plug (42) and a spring-biased piston (30), both plug (42) and piston (30) being positioned within a single bore (B) of the device. The plug (42) is meltable out of the bore when the wheel (12) temperature increases above a specific limit set by the eutectic material which frees the piston (30) to move out of a spring-biased and bore-sealing position within a sealing ring (22) by an overpressure within the tire which overcomes the spring bias. The piston (30) will return to a sealing position when the pressure drops below a value which is insufficient to overcome the spring bias.
Is it possible that the tires did not "blow up?"
The link below is a brief summary of tire fuse plugs, which this 767 has. The design is intended to prevent tires from "blowing up." However, I was not there, and I did not speak with the Alitalia maintenance crew as you did.
http://www.freepatentsonline.com/4535957.html
A device (10) for venting aircraft tires comprises a fusible plug (42) and a spring-biased piston (30), both plug (42) and piston (30) being positioned within a single bore (B) of the device. The plug (42) is meltable out of the bore when the wheel (12) temperature increases above a specific limit set by the eutectic material which frees the piston (30) to move out of a spring-biased and bore-sealing position within a sealing ring (22) by an overpressure within the tire which overcomes the spring bias. The piston (30) will return to a sealing position when the pressure drops below a value which is insufficient to overcome the spring bias.