Bird Strike

[mutt]

I was kinda surprised yesterday to hear that one of our B747 suffered a bird strike at 35,000 feet, this caused enough damage to one engine that the flight diverted to a home airport rather than the destination.

I know that its migration season, but what sort of European birds cruise along at 35,000 feet ??

Mutt.

[lomapaseo]

Previous reports of this kind have been investigated by reviewing the DFDR or FADEC along with collection of laboratory examination bird debris/species from the engine.

All such investigations have disproven high altitude strikes.

[OzExpat]

ALLLLL high altitude bird strikes have been disproved? Forgive my confusion, but what cause are we left with? :eek:

[lomapaseo]

>ALLLLL high altitude bird strikes have been disproved? Forgive my confusion, but what cause are we left with?<

That they occurred earlier in the flight.




Sherlock

[BlueEagle]

Over South America Condors have been seen/collided with well above 30,000'. Ask Lufthansa.

[mutt]

lomapaseo,

I found your comments extremely interesting, but was waiting to see if there were any other responses, these are the facts that i know of...

1: Night time takeoff
2: 3 hours into the flight, engine vibration started increasing to the extent that the engine was shut down.
3: Flight turned around to one of the airlines hubs rather than the destination.
4: Bird remnants, feathers, blood were found around the engine.


From this i can only see two options.

1: The aircraft hit bird during climb but the engine survived for up to 3 hours.
2: The aircraft hit a bird at altitude and suffered an immediate problem.



Mutt.

[RadarContact]

What problem???? :confused:

[lomapaseo]

Mutt, if you can private me through the forum hardware, I'll try to see that this does get a proper investigation, but with the passage of time I can't guarantee it.

[slingsby]

Memory failure perhaps, but some decade in the past, didn't a PanAm B747 classic suffer a bird strike in the cruise over Nova Scotia or somewhere. Impacted on the Radome and bits of the bird (a goose I seem to recall) were recovered.

[gas path]

Slingsby

Yes! I vaguely remember being involved in the repair of that. I thought that it was an eagle........but the mists of time:(
Besides the radome and scanner the fwd pressure bulkhead was badly damaged.

[Iceman49]

Couldn't there be a posssbility of a bird strike on descent, after the engine was shut down? Where is Boracay?

[lunkenheimer]

Bar-headed geese have been observed flying over the Himalayas, even over Everest, so it is at least theoretically possible to have a birdstrike at 30,000 ft. I've seen this information in several reputable journals, so tend to believe it.

Also found this report, but haven't attempted to verify:

"The altitude record is held by a Rüppell's griffon Gyps rueppelli, a vulture with a 10-foot wingspan. On November 29, 1975 one was sucked into a jet engine 37,900 feet above the Ivory Coast in West Africa"

This might be the Lufthansa incident BlueEagle is thinking of.

[Canuckbirdstrike]

Just to set the record straight.... I spent almost two years working with Transport Canada writing five chapters and editing a comprehensive safety publication on bird strikes titled "Sharing the Skies" and high altitude bird strikes do occur!

The evidence is well documented from a number of reliable sources. There is extensive radar evidence of bird movements at altitudes above 30,000 ft. in certain parts of the world. These high altitude strikes do not occur frequently, but are not unknown.

The area to pay attention to with respect to bird strike risk is operations at 10,000 ft. and below, particularly during migratory bird seasons. With increasing migartory bird populations and mean weights coupled with the current airframe and engine certification standards we all need to take care when conducting high speed operations (>250knots) below 10,000 ft. Hitting an 8 lb goose at 280 IAS at 5,000 feet can exceed the certified impact force on many aircraft.

Just something to think about during the autumn season......

[OzExpat]

I wonder if there's any research to suggest that a jet engine can eat a bird, at any altitude, and not get indigestion straight away? I'd have thought that either the engine would get sick straight away, or not at all. A local RR-Spey engine operator here gets more than their fair share of bird ingestions and it always seems to "fowl" the engine pretty much straight away.

[lomapaseo]

>I wonder if there's any research to suggest that a jet engine can eat a bird, at any altitude, and not get indigestion straight away? I'd have thought that either the engine would get sick straight away, or not at all. A local RR-Spey engine operator here gets more than their fair share of bird ingestions and it always seems to "fowl" the engine pretty much straight away.
<

They get sick right away, however in some cases the symptoms become more pronounced (and reported by the pilot) much later. Symptoms like surge or vibration

[Canuckbirdstrike]

There are a number of interesting cases of "delayed" damage to engines. A recent case led to three RTO's after boroscope inspections supposedly revealed no engine damage following a birdstrike. Each time the aircraft accelerated for take off there were compressor stalls and an RTO. Net result a new engine was installed and an interesting public relations problem for the airline.

This is not an isolated case. The lesson is to be wary following a bird strike. Visual inspections without a boroscope may not be sufficient and even the boroscope may not reveal all internal damage.

[lomapaseo]

On some older engines, the bird ingesion sometimes produced internal stator damage in a localized area which was not always detectable by borescope, thus leading to a compressor stall/surge at some pinch point like TOD etc.

On the new large fan engines, twisted blades may sound funny, but be very hard to see during walk-around. Unfortunately they may also fatigue rather rapidly in this condition.

[OzExpat]

Thanks guys, I've just learned something! :)

[Cyclic Hotline]

ACFT, UPS28, A B757, ENROUTE FROM SDF TO MHR, STRUCK A GOOSE AT FL360.

ACFT DESCENDED TO FL280, DUE TO THE WINDSHIELD BEING CRACKED AND CONTINUED ON TO DESTINATION. PILOT DID NOT DECLARE AN EMERGENCY. OVER COLORADO SPRINGS, CO

36,000 foot Goose (http://www.faa.gov/data_statistics/accident_incident/preliminary_data/media/A_1104_N.txt)

[md-100]

by the way... is it true that turning on the radar on runway before T/O and LND keeps the birds off the way??

[Old Smokey]

md-100, that one's been thrashed to death before. The consesus is absolutely NO!

I was interested to read Canuckbirdstrike's contribution (as always) wherein he states that bird movements are observable on radar. I'm aware that our Wx radar transmissions are frequency optimised to detect water droplets, and return little else except highly reflective targets. Would a second radar optimised for bird density / reflectivity be feasible? If feasible, it could be a worth-while investment.

Failing that, the only way to use weather radar to avoid birds would be to seek active thunderstorms and fly through them deliberately. No self-respecting bird would fly there:D

Regards,

Old Smokey

[Slasher]

Dont be too sure bout that Smokes! I struck a sparrow while descending through a line of thundereys into Da Nang just on dusk. His head got stuck under the wiper arm while the rest of his torso went south.

Little bugger was either stupid or accidentley got sucked up into it.

[Old Smokey]

Dammit Slasher, you just shot down my preferred bird avoidance technique.:(

Regards,

Old Smokey

[OzExpat]

Onya Slash and welcome back mate, long time no see!

[Canuckbirdstrike]

Old Smokey:

Once again the issue of using the weather radar to scare away birds is raised. This has got to be the most pervasive myth in aviation - it doesn't work!

As for your comments on a second radar unit configured for bird tracking, it is not beyond the realm of possibility.

Currently there is a great deal of research and field trial work being done with ground based radar units that provide raw data to software applications that are able to identify and track bird movements and also use predictive algorithms to generate future "threat paths". The objective is to produce a product that can be used to map potential aircraft/bird interactions and feed back the information to the flight crew. This work is well past the theoretical stage, but it will take time to refine the product and make it useable by ATC and flight crews. Discussion has also occurred on the issue of developing mechanisms to either build units for aircaft or to provide real time datalink and display information for flight crews.

I have seen the current product and am very excited with the results. I believe that the developers are well on the way to producing a practical safety enhancement tool.

Richard

[BOAC]

Mutt - having had a Pegasus (Harrier GR3) compressor disintegrate around me 6 hrs after FOD caused a stress point on a blade, have you considered prior damage? What was the reuslt of the boroscope?

[Sir George Cayley]

In the UK there's a Govt research lab with a modified missle radar set up to track birds. It has X and Y band and was imported from the US.

Being used at a far north RAF station to track Geese (Canada I think) and Gulls near ABZ too.

In terms of daily risk operating in the UK I'd put Birds second to MAPADS with runway incursion slipping as education improves.

If you fly a twin and take birds in both - who ya gonna call?

Sir George Cayley

[Blip]

Don't migratory birds migrate to AVOID the harsh winter cold (amongst other things)? If so, what the $#%$# are they doing climbing to an altitude where the temperature is around -45 degrees C??

Why would they bother expelling so much energy to climb so high? Soaring thermals associated with ground heating wouldn't get them that high. They'd have to make the effort themselves.

And don't birds suffer hypoxia??

With such little heads at the end of a long neck such as a duck or goose, with little feather insulation, wouldn't their brains just freeze solid at -45 degrees C??

I can believe that some birds might fly too close to the bottom of a very active thunderstorm and find themselve spat out the top. In fact I remember an article in an aviation magazine about planes striking snakes, mice, even fish that were probably sucked up via dust devils, tornadoes and water spouts. However I just find it hard to believe a bird would intentionally climb so high. And there would be that much super cooled water inside a thunderstorm, they'd be covered in ice and dead in no time.

[manuel ortiz]

Birds in clouds...

It was night time, descending IMC through 16000 feet when we felt the impact.
BAC 111-500, 30 years ago, radome got a prety good size hole.
Brown feathers inside the area.


Rgds.

Manuel
DC-3>>>>>>A-320

[RatherBeFlying]

Why would they bother expelling so much energy to climb so high? Soaring thermals associated with ground heating wouldn't get them that high. They'd have to make the effort themselves. My guess is that they enjoy the TAS advantage and resultant efficiency that comes with altitude -- same physics as with airplanes. Winds at altitude tend to be faster and they do generally wait for winds in the right direction.

Too bad it's geese and swans that like to fly high. Wing loading likely keeps ducks and loons lower down -- not that you'd want to hit one of those either.

Hit something at 2am. at 8000' -- the landing light gave me enough warning to stuff my head under the panel. Very big bang and messy windshield.

[Gargleblaster]

Can't they be equipped with a mode S transponder ? :D

[discostu]

Can't they be equipped with a mode S transponder ?

Yes, but who would tell them what to 'SQUAWK'? :p

(Sorry about that. I'll get back in the cupboard)

[forget]

Anyone have a sensible answer to Blip's question?

'With such little heads at the end of a long neck such as a duck or goose, with little feather insulation, wouldn't their brains just freeze solid at -45 degrees C??'

[stuckbee]

Googled a bit.

Seems some of these little beasts are rather resilient at 29000ft and up...

Please see http://magazine.audubon.org/birds/birds0011.html

[Blip]

stuckbee Thank you very much for that link. Isn't nature amazing!! I am now a believer.

Nice one discostu. Made me laugh. :)

[visibility3miles]

I can believe that some birds might fly too close to the bottom of a very active thunderstorm and find themselve spat out the top.


William Rankin: In 1959, Lt. Col. William Rankin was flying at 47,000 feet when he had to eject from his F8U jet over Norfolk, Virginia due to an engine failure. He parachuted into the middle of a severe thunderstorm that carried him over 65 miles to Rich Square, North Carolina. The trip took over 40 minutes.

Didier Dahran: In May of 1993, Frenchman Didier Dahran parachuted at 1,000 feet and was caught in a cyclone that lifted him to 25,000 feet. His first parachute collapsed at that point and he used his reserve to descend to earth some 30 miles from where he started. The incident happened in the vicinity of Boulac, France.

Mathieu Gagnon: In June of 2002, Gagnon was sucked into a dark storm cloud while parachuting in Ontario and was pulled up by the storm. After rising 1,000 meters, he cut away his main parachute and fell out of the clouds. Using his reserve he came down about 25 kilometers south of the airfield where he was supposed to land.

http://www.greenharbor.com/fffolder/unlucky.html

Doesn't sound like fun.

[mutt]

BOAC,

I originally opened this thread in 2004, I cant remember the outcome of the investigation.

Mutt

[unwiseowl]

I think the PanAm 747 strike over Nova Scotia was a canada goose at FL290.

[Piltdown Man]

I also believe that some swans can also get up into the low thirties. But I do know of a chap whose weather radar was taken out by a goose at FL330. They (and most of the pax) heard a very loud bang followed by the WX failing. The force of the impact pushed the radome into the scanner and stopped it moving.

[enicalyth]

So was it an official or an unofficial bird strike?

[RatherBeFlying]

Always wondered what microwaved swan would be like:}

[ColumbiaStudent]

I'm writing a story on bird strikes for my journalism class at Columbia. Are there any commercial pilots out there who'd be willing to share their story with me? I prefer to speak with someone who had a bird strike experience in or out of JFK or can point me to someone who did. Thanks for your help.

[ssg]

I tend to agree that while it's possible to hit a bird up high, maybe him being caught in an updraft, t storm, who knows, it's more likely that damage was done earlier.

Maybe a nick on a blade, that eventualy came apart, ect.

On a funny note, in the Mojave, they send chickens and turkeys through engines to test just this fact, on how they would affect an engine.

I am curious if anyone has any luck turning up the radar to get birds to move off the runway, never helped me, it doesn't move a herd of Elk either. :)

SSG

[jumpseater]

I've been doing some work on the issue, I have records of crew reports of 57 strikes above 3,000ft in a two year period, so they certainly occur, but there are far fewer than those at lower levels, i.e. below 3,000ft.

CS
pm me, with some details of what you're doing, I may be able to assist
rgds
js

[Centaurus]

One thing for sure. Maintaining 250 knots below 10,000 ft goes a long way to improving your chances of surviving a big bird hit on the windscreen. In Australia and Pacific Islands, it is normal for jets to ignore the dangers of high speed bird strike risk and they will deliberately climb/descend at 300 knots + below 10,000 ft. I have seen 737's level at 1500 ft over the sea at 300 knots ignoring the sea gull hazard. A most courageous decision...

A bird strike on the windscreen at those speeds risks windscreen shatter and crew injuries. That is why on some jets it is SOP to limit speed to 250 knots below 10,000 ft with windscreen heat inoperative, in recognition of the potential disastrous consequences of high speed bird strike.

[compressor stall]

Many years ago, flying a VFR lightie across Melbourne was told that there was unidentified traffic crossing right to left at three miles.

Turned out to be a flock of geese, and the often metal tags on birds were causing the return.

Presumably, weather radar would pick up such a return, if the bird had one on (and if you had the wx radar on, and were watching it).

[Canuckbirdstrike]

OK, once again the issue of using WX radar as a bird deterrent is raised and the answer is still the same - does not work!

Now the issue of bird strikes and altitudes..... A very interesting subject that requires careful analysis. Indeed, I authored a report for Transport Canada on this very subject in September 2002. I completed an in-depth risk analysis of operations at speed greater than 250 knots above 3,000 ft. AGL. the analysis was most revealing. I will check and see if I am able to make the report or sections of it available for all to read.

The critical point is that while the number of strikes may be lower, at higher altitudes, the size and number of birds (tend to be large flocking birds), the fact that these bird species populations and mean weights are increasing dramatically, the fact that as altitude increases at a fixed IAS the TAS increases, and certification standards a are based on a 4 lb bird at Vc at sea level is a recipe for disaster. When you look at this you see very rapidly that any larger bird at higher speed can and will exceed the certified impact force that the windscreen or aircraft structures were designed for.

What is even more interesting is when you look at the acceleration from 250 knots to 300+ knots. The rate of climb during acceleration is typically half the rate of climb for a steady state speed climb. This results in doubling the exposure and probability of striking a bird in the high risk altitudes. Couple this with the fact that the impact force increases as the square of the speed then we have the classic high-risk scenario - increased probability, exposure and severity.

The North American strike data supports this when you analyze the reported damage that these strikes incur vs. the total number of reported strikes.

Lesson learned - high-speed flight below 10,000 ft is a high risk activity that can exceed the certification standard of the aircraft and with the advent of more twin-engine aircraft and the increasing high-risk bird species populations the risk is increasing.

Richard

[ssg]

In the states, I smack birds all the time, generaly on approach.
I think it goes with out saying that hitting a bird at 100 knots is better then 300 kts.

-SSG