Bird-strike: a superb video !

Flying-Belgian · Post by **Flying-Belgian** » 05 May 2007, 11:24

We often talk about bird-strikes on this forum. In fact such incidents shouldn't be underestimated.

Watch this video with attention and untill its end:

http://www.flightlevel350.com/Aircraft_ ... -8457.html

Well played by the pilots. Incident happened last sunday...

By the way, Simon Lowe is really doing some great videos in MAN.

FB.

jumpjet · Post by **jumpjet** » 05 May 2007, 13:03

Amazing video and I was so impressed with the pilot and air traffic control.. so calm and collected and very clear in what the options were.

Post by **Bruspotter** » 05 May 2007, 13:32

Hello

Ineed an amazing video and what makes it complet is the ATC on the background. It's very nice too see what happens when a bird strike actually occurs. Good job off all people involved in solving the problem.

Best regards: Yannick

FLY4HOURS.BE · Post by **FLY4HOURS.BE** » 06 May 2007, 01:19

Nice video!!

Wrong terminology is used, PAN-PAN-PAN should have been used instead of MAYDAY-MAYDAY-MAYDAY as the aircraft was in an emergency, not a distress situation.

Bracebrace · Post by **Bracebrace** » 06 May 2007, 10:13

There are situations where an engine failure only requires a panpan. But on takeoff it's a standard mayday call in many companies.

The pilots revert to standard engine out procedures, including a standard engine out procedure (or an appropriate escape route) which usually differs from the cleared SID. The mayday gives full priority to the pilots to do whatever they think is necessary, that's also why you include your intentions ("proceeding straight ahead...").

Post by **sn26567** » 06 May 2007, 10:25

Superb video indeed. It is amazing to see how the engine was pulsing (fire and noise).

Watch specially the two last seconds of the video, where the author was able to capture the bird just before the strike.

Devon Rex · Post by **Devon Rex** » 06 May 2007, 11:46

Maybe a small technical question, but can someone explain why the engine starts making these pulsation after the birdstrike? Does it try to restart? I was more expecting a continuous trail of smoke, since I presume the engine doesn't stop running after the strike? Or am I wrong?

Post by **Bruspotter** » 07 May 2007, 20:36

Hello

Devon Rex: I think it's perfectly possible that what you hear is the engine that is beiing totally destroyed. It might be a broken fanblad that is destroying all others still running in the engine and penetrating deeper in the engine.

But anyway, I'm going to try to tell you what it is exactly, I will search further.

By the way: check out how much effort the pilot has to do to keep the plane level on the runway when landed, especially during reverse, the only running engine is pulling the plane slant out of it's wheeltrack.

Best regards: Yannick

[/quote]

FLY4HOURS.BE · Post by **FLY4HOURS.BE** » 07 May 2007, 21:24

What I don't understand is that engines are built with standars for bird-strikes. What if both engines have a bird ingestion at the same time?
I don't think you can rely on the plane's maximum glide performances in such cases...

Bracebrace · Post by **Bracebrace** » 07 May 2007, 23:51

What you see is the result of a surging compressor. The bird ingestion can cause anything from a temporary "hickup" in pressure buildup (could cause a single surge, usually no damage to the engine) to fan blade failure and total engine destruction.

If the compressor stops to provide air at the required pressure for a small period of time (ie because the bird entry distorted the airflow over the compressor blades and some blades stalled), the high pressure burning fuel/air mixture in the combustion chamber has an easier way out up front. In stead of flowing backwards, it flows forward into the compressor. In some surge cases you can see flames exiting the engine at the inlet. This forward flow creates a pressure drop in the combustion chambers and the result is that the burning fuel/air mixture is now propelled backwards again, all the way to the engine exhaust.

However, the engine is still running. It provides thrust, but not the max amount. If the compressor does not recover fast enough, the engine can become unstable (as it did in this vid). The full process will then repeat itself continuously since there is fuel supply and the compressor still rotates: pressure buildup with distorted compressor, forward flow, backward flow (burst of flames at the exhaust), pressure buildup, forward flow, backward flow (burst of flames),...

Sometimes it's a single hickup (one bang, ie in heavy crosswind takeoffs, immediate compressor recovery), sometimes the compressor is unable to recover, becomes unstable. This requires thrust reduction, or sometimes engine shutdown.

Hope this helps

FLY4HOURS.BE · Post by **FLY4HOURS.BE** » 08 May 2007, 08:31

Well thanks very much, very interesting.

Devon Rex · Post by **Devon Rex** » 08 May 2007, 12:44

Bracebrace wrote:What you see is the result of a surging compressor. The bird ingestion can cause anything from a temporary "hickup" in pressure buildup (could cause a single surge, usually no damage to the engine) to fan blade failure and total engine destruction.

If the compressor stops to provide air at the required pressure for a small period of time (ie because the bird entry distorted the airflow over the compressor blades and some blades stalled), the high pressure burning fuel/air mixture in the combustion chamber has an easier way out up front. In stead of flowing backwards, it flows forward into the compressor. In some surge cases you can see flames exiting the engine at the inlet. This forward flow creates a pressure drop in the combustion chambers and the result is that the burning fuel/air mixture is now propelled backwards again, all the way to the engine exhaust.

However, the engine is still running. It provides thrust, but not the max amount. If the compressor does not recover fast enough, the engine can become unstable (as it did in this vid). The full process will then repeat itself continuously since there is fuel supply and the compressor still rotates: pressure buildup with distorted compressor, forward flow, backward flow (burst of flames at the exhaust), pressure buildup, forward flow, backward flow (burst of flames),...

Sometimes it's a single hickup (one bang, ie in heavy crosswind takeoffs, immediate compressor recovery), sometimes the compressor is unable to recover, becomes unstable. This requires thrust reduction, or sometimes engine shutdown.

Hope this helps

Clear enough! Thanks

a380man · Post by **a380man** » 08 May 2007, 16:43

That was a nice watch and it was so calm!Poor bird!

jan_olieslagers · Post by **jan_olieslagers** » 08 May 2007, 19:31

FLY4HOURS.BE wrote:Wrong terminology is used, PAN-PAN-PAN should have been used instead of MAYDAY-MAYDAY-MAYDAY as the aircraft was in an emergency, not a distress situation.

You sure about this? I was taught to say "MAYDAY" when in dire trouble myself, and "PAN" when seeing some other plane in difficulties.
What do you consider the difference between "an emergency" and "a distress situation"?

I only hope you are very sure about your information, after all the people on the radio took profound training on the matter so I do hope they know what they're doing!

Post by **Bruspotter** » 08 May 2007, 20:22

Hello

FLY4HOURS:

What I don't understand is that engines are built with standars for bird-strikes. What if both engines have a bird ingestion at the same time?
I don't think you can rely on the plane's maximum glide performances in such cases...

Indeed , then you have like they say in dutch 'str. aan de knikker'

Yes they are build for it, but yet they will have heavy damadge every birdstrike how little it may be. BUT... the engine will keep running and if the birdstrike is whiting the 'designed damage rate' the engine kan still keep running for a wile and it can still produce a small amount of thrust if not to much damaged. But eventually it will break down or it must be replaced. I've seen some compressors/fans wich where really so terrible broken up. And yet the plane made it to the ground (talking about F-16).

Bracebrace:

Ok , thanks a lot for the answere

. Didn't know that you could hear a 'surge' so clearly. Interesting. So you can indeed clearly hear how fast compressor 'stall' and 'choke' follow up each other and create the surge. Cool

Best regards: Yannick

smokejumper · Post by **smokejumper** » 08 May 2007, 21:38

In past years, a bird strike test was performed as part of the enginne certification program. A chicken carcass was fired from a pneumatic canon at about 175 miles per hour (280 Km) into the engine. I recall seeing the neatly carved sections exiting the fan assembly.

When the chicken is fired into the turbine, it just shreads, mushes and burns.

Today, much of the testing is performed via computer simmulation, but an actual test verifys the result.

Flying-Belgian · Post by **Flying-Belgian** » 09 May 2007, 09:19

Bracebrace wrote:What you see is the result of a surging compressor. The bird ingestion can cause anything from a temporary "hickup" in pressure buildup (could cause a single surge, usually no damage to the engine) to fan blade failure and total engine destruction.

If the compressor stops to provide air at the required pressure for a small period of time (ie because the bird entry distorted the airflow over the compressor blades and some blades stalled), the high pressure burning fuel/air mixture in the combustion chamber has an easier way out up front. In stead of flowing backwards, it flows forward into the compressor. In some surge cases you can see flames exiting the engine at the inlet. This forward flow creates a pressure drop in the combustion chambers and the result is that the burning fuel/air mixture is now propelled backwards again, all the way to the engine exhaust.

However, the engine is still running. It provides thrust, but not the max amount. If the compressor does not recover fast enough, the engine can become unstable (as it did in this vid). The full process will then repeat itself continuously since there is fuel supply and the compressor still rotates: pressure buildup with distorted compressor, forward flow, backward flow (burst of flames at the exhaust), pressure buildup, forward flow, backward flow (burst of flames),...

Sometimes it's a single hickup (one bang, ie in heavy crosswind takeoffs, immediate compressor recovery), sometimes the compressor is unable to recover, becomes unstable. This requires thrust reduction, or sometimes engine shutdown.

Hope this helps

Many thanks for that explanation.

Indeed, I had already heard that noise on the tarmac in Kinshasa recently. It was when a Bravo Air Congo DC9 landed and reversed thrust. At that time, I had the same explanation from a captain.

FB.

earthman · Post by **earthman** » 09 May 2007, 11:21

smokejumper wrote:In past years, a bird strike test was performed as part of the enginne certification program. A chicken carcass was fired from a pneumatic canon at about 175 miles per hour (280 Km) into the engine. I recall seeing the neatly carved sections exiting the fan assembly.

When the chicken is fired into the turbine, it just shreads, mushes and burns.

Isn't that how McDonalds makes Chicken McNuggets?

I do recall one of those programs about the A380 where they shot something like 6 chickens at once into a RR engine.