Bird Strike
 

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.

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.

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

>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

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

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.

What problem???? :confused:

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.

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.

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.

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

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.

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......

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.

>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

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.

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.

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

36,000 foot Goose
 

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

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