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"Birdstrike, Birdstrike... going down"


ecoli

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It was an Airbus A320, but they're about the same size. Bird strikes are a familiar and frequent problem for aviation, with special measures often taken around busy airports to reduce their numbers. When they're ingested they often (usually?) break fan blades, which in turn cause so much damage that the engine more or less breaks apart.

 

The planes can fly on one engine, but in this case it sounds like BOTH engines were struck, so he had no power at all. The 320 has a little propeller it drops into the airstream when that happens in order to give it flight controls so it can glide under control, but they don't glide real far, especially at that altitude.

 

Interestingly, the 320 also has a "ditch mode", and when the pilot smacks that rarely used button all openings in the air frame (and there are a lot of them) close up in order to facilitate floating. I haven't heard yet if the pilots used it here, but it's a safe assumption given how long that thing stayed afloat even after the doors were opened.

 

It's notable that in this image the plane is perched *exactly* as it's supposed to be in this situation:

 

690px-Plane_crash_into_Hudson_Rivercroped.jpg

 

Note the nose-high attitude caused perhaps by the floats on the front doors. You just know there are engineers today at Airbus who are clapping each other on the back over that. It's absolutely perfect. 150 thousand pounds of aluminum and aviation fuel, drifting along on the surface like that was its plan all along, saving the lives of its passengers as if it were no big thing. Wonderful.

 

It also looks like the pilot managed to avoid the problems that the Ethiopian 961 pilot ran into when trying to dead-stick his 767 in 1996.

 

180px-Ditching_of_Ethiopian_Airlines_Flt_961.JPG

 

Ever since that accident there's been a kind of standing question of whether an airliner with two engines mounted under the wings could ever land on water. That question was answered today -- a very rare thing in air accident investigation.

 

On the whole it's an incredible story. My first reaction when I saw that thing in the water was "welp, there goes the streak". The US has been deadly-accident-free since August of 2006, when Comair 191 took off from the wrong runway in Kentucky. But as with the walkaway in Denver a few weeks ago, the streak continues.

Edited by Pangloss
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I'm impressed and awed. I was listening to the radio about this in the car on NPR. This pilot seems to deserve the credit being hoisted upon him. Amazing really. They were fortunate, too, for landing so close to so many tug boats and ships, who arrived at the plane within minutes of it's skipping across the water like a rock. Wild stuff.

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Engines can chop up quite a bit of bird... but at some point it is just too much. They're jet engines, not meat grinders. There have been many incidents where airplanes had to abort a takeoff because of too many birds in the engine. (For example a Ryanair airplane had a similar incident in Rome, Italy a few months ago - note all the red spots on the nose of the airplane - yuck).

 

I'm mostly impressed with the landing, because of the things Pangloss already wrote. I'd like to know the details: how did the pilot manage to land the airplane without breaking it into pieces?

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I'm guessing it's not so much a matter of whether they're powerful enough to chop up birds as it is how much tolerance such precisely engineered machines have for getting dinged up. But yeah, pretty amazing landing nonetheless. Usually when you hear that many sirens it's big trouble, but that landing looked like it would have actually been fun if you knew you were going to survive it (and if it wasn't so effing cold out). The sight of a jetliner bobbing peacefully down the river was pretty surreal.

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I just figured that the engines and propellers on that thing must be pretty darn big. Then again, Canada geese are fairly large birds themselves so it would be a lot of meat and bone to chop up.

 

 

Destroyed jet engine due to bird strike. Aircraft on takeoff phase, 50 ft. AGL, 140 knots.

BirdAvoidance4.jpg

 

 

 

View of Fan blades of JT8D Jet engine after a bird strike

800px-JT8D_Engine_after_Bird_Strike.jpg

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if the blades were stationary then a blade would be fine after getting impacted by a bird at a few hundred miles an hour, the fact that it is under lots of stress from spinning really fast(especially so under take off conditions where a higher throttle setting is used and there is a change in air temperature as the plane rises) makes it much more likely to fail when hit by something, like a bird. if enough blades are damaged badly enough, the engine will break apart and hopefeully the kevlar shielding on the inside of the casing will do what it is designed to and hold all the shrapnel in as it could easily pierce the fuselage.

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According to New Scientist, jet engine regulations require that they be able to ingest small birds without incident. For larger birds, they just require that the engine not explode. Bird-proofing the engines is technically possible, but would drastically decrease the efficiency of engines, which would be a large continuous cost, and likely also a constant danger due to less power at takeoff.

 

http://www.newscientist.com/article/dn16438-comment-why-we-cant-stop-birds-downing-aircraft.html

 

Reminds me of a joke I heard (I remembered the joke as being about a plane, but oh well)

Message --- Sometimes it DOES take a Rocket Scientist!!

Scientists at NASA built a gun specifically to launch standard 4 pound

dead chickens at the windshields of airliners, military jets and the space shuttle,

all traveling at maximum velocity. The idea is to simulate frequent incidents of

collisions with airborne fowl to test the strength of the windshields.

 

British engineers heard about the gun and were eager to test it on

windshields of their new high speed trains. Arrangements were made,

and a gun was sent to the British engineers. When the gun was fired, the

engineers stood shocked as the chicken hurled out of the barrel,

crashed into the shatterproof shield, smashed it to smithereens, blasted

through the control console, snapped the engineer's back-rest in two, and

embedded itself in the back wall of the cabin, like an arrow shot

from a bow.

The horrified Brits sent NASA the disastrous results of the

experiment, along with the designs of the windshield and begged the US

scientists for suggestions.

 

NASA responded with a one-line memo --

"Defrost the chicken."

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  • 3 weeks later...

This is insane. Here is audio between the pilot and the air traffic controllers. It's like they're discussing what they are having for dinner. Amazing.

 

 

http://www.nytimes.com/2009/02/06/nyregion/06crash.html?ref=nyregion

In the recording, Captain Sullenberger’s voice is deep and a bit gravelly, with a brisk cadence and clipped syntax that is normal for communications between cockpits and controllers. If there was a sign of stress, it was that the captain fumbled his call sign; “Cactus” is the correct sign for US Airways, but he was Flight 1549, not 1539.

 

The controller replied instantly, “O.K., yeah, you need to return to La Guardia; turn left heading of, uh, 220,” that is, to the left. Captain Sullenberger acknowledged, and instantly the controller, in a windowless radar room at the New York Terminal Radar Approach Control on Long Island, used a land line to reach the control tower. “Tower, stop your departures. We got an emergency returning,” he said.

 

The controller’s voice was urgent but not evidently stressed, until he, too, bungled the call sign, calling it “1529.”

 

The controller turned his attention back to the plane. “Cactus 1529, if we can get it to you, do you want to try to land Runway 1-3?”

 

Captain Sullenberger was in the unusual position of both flying an airliner and working the radio; talking on the radio is normally the job of the other pilot, but in this case the first officer, Jeffrey B. Skiles, was running through an “engine restart checklist.”

 

“We’re unable. We may end up in the Hudson,” Captain Sullenberger replied, at 3:28:11, less than a minute after his first communication about the unfolding emergency.

 

The controller offered him directions to the runway.

 

“Unable,” Captain Sullenberger responded, in standard pilot phraseology.

 

The other La Guardia runway was also available, the controller said, and Captain Sullenberger replied, “I am not sure if we can make any runway,” and asked about “anything in New Jersey, maybe Teterboro.” Given a routing there, he replied, “We can’t do it.”

 

“O.K.,” said the controller. “Which runway would you like at Teterboro?”

 

“We’re gonna be in the Hudson,” the captain replied. He never used the word “emergency,” although the controllers in the radar room on Long Island and the towers at La Guardia and Teterboro reacted instantly as they were drawn into the problem.

 

His last communication was at 3:29:28, a few hundred feet over the Hudson.

 

Captain Sullenberger, the co-pilot and three flight attendants will describe their experiences in an interview with Katie Couric on “60 Minutes,” scheduled to be broadcast on Sunday on CBS, which released a short transcript of the interview on Thursday.

 

 

Full audio on the left of the page at the link above.

 

"We're unable. We may end up in the Hudson."

Out-friggin-standing. I'm really looking forward to the 60 Minutes interview this Sunday.

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Yeah I heard that earlier today, and was really impressed not only by the pilot's calm but by the professionalism and rapid action of the controllers. Especially with the Teterboro guy, who accepted without hesitation something that likely represented hours of tedious, time-consuming work to get back on schedule.

 

Pilots will tell you that the controllers in that part of the country are the best in the world. I guess that's a good example of that.

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Indeed. I recall a documentary about a British Airways flight that went through volcano ash which subsequently killed all engines of the 747.

 

http://en.wikipedia.org/wiki/British_Airways_Flight_9

 

Actually the whole appeared to be extremely calm regarding the circumstances. Although, they had the advantage of being British.

 

Ladies and gentlemen, this is your captain speaking. We have a small problem. All four engines have stopped. We are doing our damnedest to get it under control. I trust you are not in too much distress.'
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  • 4 weeks later...

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