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-   -   bird avoidence (https://www.pprune.org/tech-log/481297-bird-avoidence.html)

lomapaseo 6th April 2012 14:11

Canuckbirdstrike


...... So let's take a look at some of your statements:

Here is what I would provide as comment: .....

an excellent reply in a technical forum :ok:

It makes it much easier for the rest of us to sort out the pros & cons of the various opinions

Canuckbirdstrike 6th April 2012 14:22

A321, the Airbus document and a similar Boeing document are very basic and quite generic.

My link to the Transport Canada document earlier in this thread is far more detailed. Use in combination with manufacturer's information you get a more rounded view.

Lomapaseo, thanks for the thumbs up. I am more than a little frustrated at times with the misleading material that can appear on this site, particularly about this subject.

The issue of bird and wildlife risk mitigation is complex and as an industry we have not been good at working with wildlife experts to compliment their activities and lower the risks.

There have been two very close calls in the last few years, aircraft were written off, but no one died. We may not be so lucky the next time.

Escape Path 6th April 2012 21:14

Maybe I'm extremely over-simplifying things but I decided to do nothing against birds, at least not when the required manoeuvre would make my aircraft look like a fighter jet. Here's why:

A bird can weight anything from 6 to 12-ish pounds (maybe more, yes), my aircraft weights 12.500lbs at full load. You people in the heavyweights have bigger masses. So the bird is lighter, hence it can manoeuvre more easily and with less effort and in less time as well

One way or another a bird has been flying for millions of years, since it is evolution what has allowed it to fly the way it does, hence it's got millions of years of experience at flying. Us? Well, we've been flying for a bit over 100 years and we were not "designed" to fly anyway, so we're out of our environment when we are in the sky.

So, if you are in a position where an "extreme" or abrupt manoeuvre is required to ATTEMPT to avoid a bird you are the least likely to make the avoidance succeed, whereas the bird can just twist a wing a wee bit and they can fly towards their intended direction with a little help from it's survival instinct. Even so, the bird weights just a few pounds, not thousands or even hundreds of thousands of pounds, so the required effort for the bird is much much less than your effort required to steer the aircraft away from the bird.

Trying to fly away from the bird can have big chances of coming across something similar to this:


The only bird we hit in over 600 landings there it was the FO flying and at 500 ft on take off we both saw the turkey buzzard in our path following our turn so we reversed the turn and the buzzard did too. We reversed again and the buzzard followed. The FO said they always dive so we pulled up as much as we could and the buzzard did likewise
I find it similar to when a car is about to hit you while you're walking on the street; the driver knows he has to dodge you and (regularly) will try to do so and he decides early enough where does he wants to steer. However, if YOU then try to get out of danger by designing your own escape you create a bigger chance for you to be hit by the car. The solution? Stay still and let the driver follow through his manoeuvre. Same with the bird/aircraft scenario; too close to the bird? Don't move, let it dodge you instead of you dodging the bird.

I agree, though, with avoiding the spot where the flock is if you have spotted the flock with sufficient time and distance to do so without a fighter jet-type manoeuvre. If the required manoeuvre is such that it would make you look all Top Gun, you're too close now and you should let the bird dodge you.

Bahrd 8th April 2012 22:16

What about balloons?
 
Thank you all for a very informative thread.
I would like to ask about a somehow related issue: the small balloons with cameras.
This hobby has became popular recently and I wonder to what extent it is safe?
See e.g. the video:
.
In particular, look at:
  • 2:32 - to asses the size of the balloon, and
  • 3:52 - to note the proximity of the plane.
Is it really scary, or am I a paranoid?

bubbers44 8th April 2012 23:29

EP I guess I didn't explain well enough my gentle banks of 10 to 15 degrees didn't resemble F18 evasive tactics. I never had a passenger complain when I was maneuvering around turkey buzzards that if I hadn't used visual avoidance of their multiple flocks would have I am sure had multiple groundings of our 757. You just have to look far in front of you to make it gentle maneuvers. Your battering ram approach of your mass is bigger so why not fly through the flock is flawed. A simple maneuver of not over 15 degrees of bank will easily avoid the problem.

bubbers44 8th April 2012 23:34

Sully, do you have any input on this as far as let the birds do the deviating?

Machinbird 9th April 2012 00:28

What about balloons?
 

I would like to ask about a somehow related issue: the small balloons with cameras.
This hobby has became popular recently and I wonder to what extent it is safe?
Not particularly safe at all. It is a big sky, but the payload looks to be large and dense enough to damage an engine/or dent an airframe.

If this is not using a transponder to report its presence, air traffic control would have issues with it. Is it insured against damage to others? The participants might be getting a knock on the door from the government when they realize just what is going on.

Escape Path 9th April 2012 01:38

@ Bubbers
 

EP I guess I didn't explain well enough my gentle banks of 10 to 15 degrees didn't resemble F18 evasive tactics. I never had a passenger complain when I was maneuvering around turkey buzzards that if I hadn't used visual avoidance of their multiple flocks would have I am sure had multiple groundings of our 757. You just have to look far in front of you to make it gentle maneuvers. Your battering ram approach of your mass is bigger so why not fly through the flock is flawed. A simple maneuver of not over 15 degrees of bank will easily avoid the problem.
I actually agree with you. What I said was IF you can avoid the bird(s) by doing gentle manoeuvres, such as what you describe, and by looking out far ahead enough, that's the way to do it. What I meant though, was that I've seen pilots that notice birds when they are too close already and then try to somehow miss them by making turns that would make a F-22 look rubbish. It's too late now and by that moment, you should let the bird avoid you instead of the other way around, given that the bird can change flight path more rapidly than you can.


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