Question for RumRunner

[Linda Z]

I'm asking you because you seem qualified to answer.

I've been thinking ever since the US Airways flight had to ditch into the Hudson River, why hasn't someone come up with some sort of device that's mounted on these planes that would scare the birds away? Or have they, and it just isn't effective? I wonder if there's a sound, or a pitch of sound that would frighten the bejeezus out of them and make them fly the other way instead of straight into the front of a jet engine.

I gather from the news reports that these occurrences are quite rare, but sheesh, if I were one of those people swimming around in the freezing cold river, I'd be wishing someone had invented such a thing.

Is it simply not practical? What do you think?

[RumRunner]

Thanks for asking - a couple of comments interspersed below - however understand I am an applied mathematician not a fluid dynamicist.

I'm asking you because you seem qualified to answer.

I've been thinking ever since the US Airways flight had to ditch into the Hudson River, why hasn't someone come up with some sort of device that's mounted on these planes that would scare the birds away? Or have they, and it just isn't effective? I wonder if there's a sound, or a pitch of sound that would frighten the bejeezus out of them and make them fly the other way instead of straight into the front of a jet engine.

That technology is already "in place." A lot of coastal airports, where sea birds are a major issue, use "cannons" (no actual projectiles) to scare the birds off. The problem with airports in general is that birds go deaf - sooner or later no sound is heard - no cannon - no jet engine - and in coastal areas the size of bird flocks tends to be much higher than inland areas - and of course - birds fly - as do planes - there have been ornithologists who have suggested that there may be a "mother" relationship between the bird and the plane - "big bird" as it were.

I gather from the news reports that these occurrences are quite rare, but sheesh, if I were one of those people swimming around in the freezing cold river, I'd be wishing someone had invented such a thing.

They are not as rare as you might think. Birds routinely enter engine intakes. All planes certified to land in the US have to be able to handle a 4lb bird in the intake. However people don't generally know how delicate the stators (the small vanes in the from end compressor stage) are.

Is it simply not practical? What do you think?

Now to answer a question you didn't ask but it would the next logical question for you to ask. Jet or turbine engines have three stages - the first being a multi level compressor stage - typically three compressors. People have asked me about whether or not you could screen the front end of the engine intake. The simple answer is no. The compression stage requires enormous air intake - and even though in the end a lot of it is shunted around the igniter stage rather than through it the compression stage itself requires enough intake to compress "tightly" Once compressed you use the bit you need and shunt the rest - BUT you need that much input to get it that compressed.

Hope that helps - anything else I could post would be filled with rather boring mathematics

Best,

RR

[Linda Z]

Thanks, RR. It never occurred to me that birds might go deaf if they live around an airport...interesting.

As for the last part of your answer, when I first started thinking about this, I envisioned some sort of a shield in front of the engine, but then I realized, oh duh, that wouldn't work because it would block the air intake.

Maybe they should paint all airplanes to look like giant, mean-looking hawks, ready to swoop down and devour smaller birds. Then only hawks (and maybe whatever preys on hawks) would be all they had to worry about.

One more reason to be nervous about flying. Yippee!

[Rocky]

Thanks, RR. It never occurred to me that birds might go deaf if they live around an airport...interesting.

As for the last part of your answer, when I first started thinking about this, I envisioned some sort of a shield in front of the engine, but then I realized, oh duh, that wouldn't work because it would block the air intake.

Maybe they should paint all airplanes to look like giant, mean-looking hawks, ready to swoop down and devour smaller birds. Then only hawks (and maybe whatever preys on hawks) would be all they had to worry about.

One more reason to be nervous about flying. Yippee!

One more reason for wusses like me to just NOT GET IN an airliner!

I imagine if I lived next to a runway without something to block the noise, I'd go deaf pretty quickly!

All in all, compared to other incidents in the NYC area with planes going down, THIS was amazingly NON-tragic. I'm very thankful for the outcome.

I don't know how Sully can be honored enough, yet maintain his humanity without getting too big for his captain's hat.

[RumRunner]

One more reason to be nervous about flying. Yippee!

LOL no sweat Linda - you have approximately a seven times higher chance of dying in a car wreck than in a plane wreck.

[Linda Z]

Yeah, yeah, I know. It's just the thought of that realllllllly long drop!

[now I see]

I imagine if I lived next to a runway without something to block the noise, I'd go deaf pretty quickly!

LOL!!!!  Some people gladly pay hundreds of thousands if not millions of dollars to live next to airports.  :)

Edited January 18, 2009 by now I see

[coolchef]

rr

what great info

i learned something tonight

thanks

[Linda Z]

LOL, now i see, now that you mention it, I do live close to a large airport. I can practically count the rivets on the bellies of the planes as they buzz over my house during landing. I'm not deaf yet, but then I'm not a little birdie. Maybe we can get them hearing aids so they'll get the he|| out of the way!

[now I see]

Well...I meant more like this...

Edited January 18, 2009 by now I see

[RumRunner]

Thanks CoolChef - glad I was able to at least one useful thing today...

rr

what great info

i learned something tonight

thanks

[Rocky]

LOL!!!! Some people gladly pay hundreds of thousands if not millions of dollars to live next to airports. :)

I used to live less than a mile from one of those airports (Stellar Airpark, Chandler, AZ)... but noise isn't as much of a problem there... I used to live only a couple of blocks to the west (to the right of the area pictured) from here... click this link to read the captions where the pic is actually posted.

well... it didn't like my pic URL so it wouldn't post... but you can see it if you click the link above...

And Linda... that's why I mentioned about having something to block the noise...

this pic was taken directly above a school... which arrogant pilots often buzzed... but that's a different issue altogether.

[kimberly]

Remember Payne Stewart. Correct me if I am wrong but I think it was a bird that flew into the windshield of his lear jet.

[now I see]

Payne Stewart's plane was on auto pilot and went down in S Dakota when it used up all it's fuel.  The NTSB concluded crew incapacitated with lack of cabin pressure as the cause, but no one knows exactly why since all the evidence was destroyed when the plane crashed, they pretty much went straight in at a high rate of speed.  

The fighter jet pilot's that were deployed when  Air Traffic Control (ATC) discovered there was no response while in flight, noted the windows were all glazed over from the inside, which suggests a rapid decompression occurred at altitude, the ATC reported the Lear cruised up to about FL 450, or about 45,000 ft at one point, and if the rapid decompression occured at that altitude or above FL 300, all onboard would be passed out within seconds.  

The Lear 35 series jet the crew was flying had known problems with their O2 system and had departed without filling the canisters.  This flight became famous because of the relatively small numbers of runaway plane flights and because Payne was a well known golfer.  A birdstrike would be an unlikely cause, but it could be possible.

Rocky, I have been to Stellar Airpark, great place, there's a guy there that has a P-51 (WWII fighter plane aka P-51 Mustang) there, awesome plane, very distinct sound to it's piston radial engine, similar to what you might hear on a WWII war movie.  Music to the ears of aviators..btw :) .  

Also Stellar has a flight training center there, which may be part of the reason you heard low level a/c noise due to student's mistakes, and from the pic, if the school was due north of the runway, it would be in the flight path on approach to land or take off, which may account for low level flying by some.  There are notices to all airman that fly in or out of that airport to be aware of overflight of residential areas and noise, so those should have been observed.  Noise is a big problem due to urban sprawl and the fact that when alot of these airparks, airports, and runways were built, there were few houses there at the time.   Too bad not everyone likes that sound ..

Edited January 18, 2009 by now I see

[Rocky]

Payne Stewarts plane was on auto pilot and went down in S Dakota when it used up all it's fuel. The NTSB concluded lack of cabin pressure as the cause, but no one knows exactly why since all the evidence was destroyed when the plane crashed, they pretty much went straight in at a high rate of speed.

The fighter jet pilot's that were deployed when Air Traffic Control (ATC) discovered there was no response, noted the windows were all glazed over from the inside, which suggests a rapid decompression occurred at altitude, the ATC reported the Lear cruised up to about FL 450, or about 45,000 ft at one point, and if the rapid decompression occured at that altitude or above FL 300, all onboard would be passed out within seconds.

The Lear 35 series jet the crew was flying had known problems with their O2 system and had departed without filling the canisters. This flight became famous because of the relatively small numbers of runaway plane flights and because Payne was a well known golfer. A birdstrike would be an unlikely cause, but it could be possible.

Rocky, I have been to Stellar Airpark, great place, there's a guy there that has a P-51 (WWII fighter plane aka P-51 Mustang) there, awesome plane, very distinct sound to it's piston radial engine, similar to what you might hear on a WWII war movie. Music to the ears of aviators..btw :) .

Also Stellar has a flight training center there, which may be part of the reason you heard low level a/c noise due to student's mistakes, and from the pic, if the school was due north of the runway, it would be in the flight path on approach to land or take off, which may account for low level flying by some. There are notices to all airman that fly in or out of that airport to be aware of overflight of residential areas and noise, so those should have been observed. Noise is a big problem due to urban sprawl and the fact that when alot of these airparks, airports, and runways were built, there were few houses there at the time. Too bad not everyone likes that sound ..

No, noise wasn't/isn't the problem. There are property tax issues that would bore people for me to go into here (and it's not pertinent to this discussion)... otherwise, it was an interesting addition to the neighborhood.

My daughter (now 19) went to school, from Kindergarten through 5th grade at the school with the playground that pilots sometimes buzzed... yes, they have a flight school and several other businesses on the East side of the runway... and homeowners, some of whom have hangers attached to their homes, on the West side.

And my understanding of the Payne Stewart incident is that when the cabin depressurized, the oxygen supply system didn't kick in... and everyone was dead within minutes (asphixiation) while the autopilot flew until it ran out of fuel.

[now I see]

Cheap thrills for the students, stiff penalties for pilots buzzing school fields! 

You're right, the pressure loss is the main thing that affected all on board Payne's airplane, if no pressure was lost, then it probably would have been an uneventful flight as oxygen is present in the atmosphere even at 30,000 ft, just not enough pressure. 

Another similar case recently was Helios Airways out of Greece, flight 522, where under a slow depressurization, all 121 souls on board lost their lives as the plane lost altitude, ran out of fuel, and descended into a hillside.

Edited January 18, 2009 by now I see