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Why no bird strike mechanisms these days?

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  • 24-02-2019 9:29pm
    #1
    Registered Users Posts: 15,913 ✭✭✭✭


    OK,

    I have no idea. I am not an aviator, but enjoy reading the threads here.

    So I just wondered (in my amateur mode), what are the reasons a shield cannot be put in front of the engines in case of bird strike? I am sure someone will tell me.

    I am very well aware of Cully Sullemburger on the Hudson. Kudos.

    Seems weird to me, that with all the electronics etc. available that a bird can take a bird down.


Comments

  • Registered Users Posts: 2,979 ✭✭✭Stovepipe


    A shield, such as a wire mesh, in front of any jet engine would disturb the airflow into the inlet and it would be very inefficient and you would have to have some means of de-icing it as it would ice up in flight. Engines do have wire mesh shields put in front of them when being tested by the manufacturer. So, it wont happen to standard engines on airliners.


  • Registered Users Posts: 15,913 ✭✭✭✭Spanish Eyes


    Stovepipe wrote: »
    A shield, such as a wire mesh, in front of any jet engine would disturb the airflow into the inlet and it would be very inefficient and you would have to have some means of de-icing it as it would ice up in flight. Engines do have wire mesh shields put in front of them when being tested by the manufacturer. So, it wont happen to standard engines on airliners.

    Thanks. But no real reason either?


  • Registered Users Posts: 2,781 ✭✭✭amen


    a little off topic but can you notice the bird in time ?

    https://www.youtube.com/watch?v=OTCqDmvg0iQ


  • Moderators, Business & Finance Moderators, Motoring & Transport Moderators, Society & Culture Moderators Posts: 68,015 Mod ✭✭✭✭L1011


    You were given the reasons in that post.


  • Registered Users Posts: 15,913 ✭✭✭✭Spanish Eyes


    L1011 wrote: »
    You were given the reasons in that post.

    Yes thanks. I know, but the fact that the poster mentioned that shields were put up in trial flights made me think about why not in commercial flights.


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  • Registered Users Posts: 644 ✭✭✭faoiarvok


    Yes thanks. I know, but the fact that the poster mentioned that shields were put up in trial flights made me think about why not in commercial flights.

    I think that poster probably meant ground tests of the engine in a test building.

    I’m pretty sure all a wire mesh travelling at ~250km/h is going to do is mince the bird before it goes into the engine, which the fan blades are going to do anyway.

    Edit: ...and add a far more dangerous and damaging object with the potential to be ingested into the engines.


  • Registered Users Posts: 15,913 ✭✭✭✭Spanish Eyes


    faoiarvok wrote: »
    I think that poster probably meant ground tests of the engine in a test building.

    I’m pretty sure all a wire mesh travelling at ~250km/h is going to do is mince the bird before it goes into the engine, which the fan blades are going to do anyway.

    Edit: ...and add a far more dangerous and damaging object with the potential to be ingested into the engines.

    Thank you. To me, it is an interesting topic.

    I just wondered if there was ever a way to prevent a Hudson River episode again.

    Airports seem to be on the ball with birds although it must cost them to do this.

    Anyway I just wondered.


  • Registered Users Posts: 14,325 ✭✭✭✭ednwireland


    Yes thanks. I know, but the fact that the poster mentioned that shields were put up in trial flights made me think about why not in commercial flights.

    the shields are only there on the test beds to get stuff getting sucked in. your running the engines in buildings on test beds all manner of stuff lying around.
    bird strikes rarely cause big damage. unless you get a lot of birds. big birds fired at the engines and blocks of ice during testing.
    https://youtu.be/BnnxqQj_dDs

    only big damage I've seen is an engine cowling hit by an eagle in India.
    you get nicks on blades. mostly it's minced and slightly warmed.
    if you're going to put a cover over it it adds weight and disrupts the airflow, its only a big issue with flocks of birds.


  • Moderators, Business & Finance Moderators, Motoring & Transport Moderators, Society & Culture Moderators Posts: 68,015 Mod ✭✭✭✭L1011


    Yes thanks. I know, but the fact that the poster mentioned that shields were put up in trial flights made me think about why not in commercial flights.

    Because of the reasons they gave in that post...

    Inefficient and would need to have anti ice systems which would be a further inefficiency


  • Registered Users Posts: 15,913 ✭✭✭✭Spanish Eyes


    Thanks for the responses. I have to say I am still none the wiser!

    What prompted my OP was looking at the Hudson River crash, I could not believe that a bird strike could cause something like that.

    Anyway. Appreciate the info.


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  • Registered Users Posts: 644 ✭✭✭faoiarvok


    Thanks for the responses. I have to say I am still none the wiser!

    What prompted my OP was looking at the Hudson River crash, I could not believe that a bird strike could cause something like that.

    Anyway. Appreciate the info.

    The Hudson incident involved a flock of geese rather than just one bird, which is the more “usual” and relatively uneventful type of bird strike.

    The investigation found that each engine ingested at least 2 Canada geese, which are obviously larger than most birds encountered by aircraft.
    2.2.2 Identification of Ingested Birds
    The Smithsonian Institution analyzed the feather and tissue samples from both engines and determined that the left engine contained both male and female Canada geese remains, indicating that the engine ingested at least two geese. (The average weight of a male Canada goose is from 8.4 to 9.2 pounds, and the average weight of a female goose is from 7.3 to 7.8 pounds.) The Smithsonian Institution report stated that only male Canada goose remains were found in the right engine, suggesting that it might have only ingested one bird; however, a
    comparison of the physical features and quantity of the damage in the two engines, which will be discussed in the following sections, indicated that the right engine ingested at least two Canada geese.

    All together, a really unfortunate and extremely unlikely situation which isn't typical of bird strikes as a whole.


  • Registered Users Posts: 2,139 ✭✭✭What Username Guidelines


    Thanks for the responses. I have to say I am still none the wiser!

    What prompted my OP was looking at the Hudson River crash, I could not believe that a bird strike could cause something like that.

    Anyway. Appreciate the info.

    The Hudson River incident was a massive outlier, not only because they completed a successful water landing, but because it was multiple bird strikes that effected both engines. Given the sheer number of flights that go without birdstrikes every single day, it’s not something that warrants such inefficient precautions.

    Edit: what faoiarvok said


  • Registered Users Posts: 15,913 ✭✭✭✭Spanish Eyes


    faoiarvok wrote: »
    The Hudson incident involved a flock of geese rather than just one bird, which is the more “usual” and relatively uneventful type of bird strike.

    The investigation found that each engine ingested at least 2 Canada geese, which are obviously larger than most birds encountered by aircraft.



    All together, a really unfortunate and extremely unlikely situation which isn't typical of bird strikes as a whole.

    It is usually the extremes that cause disasters. But I get your point.


  • Registered Users Posts: 23,296 ✭✭✭✭mickdw


    I wonder if some form of deflector/ protector could be designed to trigger if Bird was detected passing nose of aircraft.
    At say 200 miles per hour, or 88 m/s, I'd imagine there would easily be time to trigger some airbag type reaction where a bird would be detected. This would trigger a fine grille or deflector in front of the engine intake. Yes the engine would then loose efficiency but I'd imagine it might still give reasonable power and system would then be reset on the ground.
    With say 20m from nose to engine, there would be nearly quarter of a second to position device opon triggering.


  • Registered Users Posts: 644 ✭✭✭faoiarvok


    mickdw wrote: »
    I wonder if some form of deflector/ protector could be designed to trigger if Bird was detected passing nose of aircraft.
    At say 200 miles per hour, or 88 m/s, I'd imagine there would easily be time to trigger some airbag type reaction where a bird would be detected. This would trigger a fine grille or deflector in front of the engine intake. Yes the engine would then loose efficiency but I'd imagine it might still give reasonable power and system would then be reset on the ground.
    With say 20m from nose to engine, there would be nearly quarter of a second to position device opon triggering.

    Yeah, let’s add some explosives to the mix /sarcasm

    Even if detecting passing birds was as easily done as said, the vast majority of birds that pass the nose of the aircraft within half of the wingspan still aren’t going to go near the engines, but now you’d be firing some system which adds new potential FOD to the mouth of the engine, and then needs to be reset/replaced even if it didn’t prevent the engine ingesting a bird which it’s been designed to handle comfortably. Or if the bird does hit the grille, it gets sliced up and ingested anyway, or worse, takes some of the grille with it into the engine.

    Even if none of the above was a problem, I bet the cost of extra fuel to carry these systems (before even considering development, fitting, maintenance, and resetting fired devices) would be many many times higher than the cost of repairing/replacing the occasional bird-damaged engine.


  • Registered Users Posts: 2,979 ✭✭✭Stovepipe


    while mass bird strikes are rare, they do happen and the Hudson River A 320 wasn't the first. A four engined AWACs aircraft crashed on take off at Aviano, Italy because of mass ingestion of birds. Bird strikes are simply part of the cost of moving humans through the sky.


  • Registered Users Posts: 23,296 ✭✭✭✭mickdw


    faoiarvok wrote: »
    mickdw wrote: »
    I wonder if some form of deflector/ protector could be designed to trigger if Bird was detected passing nose of aircraft.
    At say 200 miles per hour, or 88 m/s, I'd imagine there would easily be time to trigger some airbag type reaction where a bird would be detected. This would trigger a fine grille or deflector in front of the engine intake. Yes the engine would then loose efficiency but I'd imagine it might still give reasonable power and system would then be reset on the ground.
    With say 20m from nose to engine, there would be nearly quarter of a second to position device opon triggering.

    Yeah, let’s add some explosives to the mix /sarcasm

    Even if detecting passing birds was as easily done as said, the vast majority of birds that pass the nose of the aircraft within half of the wingspan still aren’t going to go near the engines, but now you’d be firing some system which adds new potential FOD to the mouth of the engine, and then needs to be reset/replaced even if it didn’t prevent the engine ingesting a bird which it’s been designed to handle comfortably. Or if the bird does hit the grille, it gets sliced up and ingested anyway, or worse, takes some of the grille with it into the engine.

    Even if none of the above was a problem, I bet the cost of extra fuel to carry these systems (before even considering development, fitting, maintenance, and resetting fired devices) would be many many times higher than the cost of repairing/replacing the occasional bird-damaged engine.

    There is nothing dangerous about incorporating an explosive where it's max potential is to carry out the deployment of bird protection system.
    I believe detecting birds is as easy as described with todays tech and could very likely accurately predict point of impact with aircraft too making false firing of the system less of an issue.
    It's not so much cost versus engine damage that I was thinking, more cost of system versus loss of plane but unfortunately the industry doesn't see it that way and the loss of a plane and everyone on board is a price the industry is happy to pay if it costs less than introducing a safety system.
    I don't believe it's crazy and could be incorporated into new aircraft if the willingness of the industry was there.


  • Registered Users Posts: 7,525 ✭✭✭kona



    only big damage I've seen is an engine cowling hit by an eagle in India.
    you get nicks on blades. mostly it's minced and slightly warmed.
    if you're going to put a cover over it it adds weight and disrupts the airflow, its only a big issue with flocks of birds.

    A single bird is well capable of destroying a engine. If it goes into the core theres a whole load of inspections to be done. Plenty of engine have been wrote off due to a single bird.


  • Registered Users Posts: 16,573 ✭✭✭✭banie01


    Some Military aircraft in particular Sukhoi and later model MiG have FOD(Foreign Object Debris) protection integrated into their intake design.
    This application operates at low speeds and is intended to allow the aircraft to be much more easily deployed to semi prepared airfields.
    It operates on a combination of low speed actuated mesh grilles and louvred intake doors on the upper intake surface.

    There are a number of reasons why it more feasible for military aircraft to use a system such as this, including the use of geometrically precise ducted intakes, necessity of rough field operations and ensuring serviceability that in a civil aircraft aren't either cost effective or at all practical.

    Bird strike is really only a safety issue at low speed or take off, much more dangerous to an aircraft is the ingestion of FOD on taxiing or take-off and more effort is directed at eliminating those risks rather than bird strike.


  • Registered Users Posts: 5,854 ✭✭✭Cordell


    if the willingness of the industry was there
    It is. The could easily half the cost of the planes if they remove all the equipment that is there just for passenger safety reasons - from redundant avionics to the oxygen delivery system. They are willing to improve the safety wherever it is feasible to do so, not necessary because they are the good guys, but because loosing planes and passengers it's extremely expensive.


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  • Registered Users Posts: 644 ✭✭✭faoiarvok


    mickdw wrote: »
    the loss of a plane and everyone on board is a price the industry is happy to pay if it costs less than introducing a safety system.

    That is absolutely not true. If it were, plenty of systems in widespread use would not exist, as the cost of carrying them is greater over the long term than the financial cost of replacing an airplane and paying compensation.

    The issue is that an effective, economical system that doesn't itself increase the risk of malfunction doesn't yet exist. I don't believe what you propose is that system, for the reasons already put forward.


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