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-   -   jet/bird evasive action (https://www.pprune.org/tech-log/442589-jet-bird-evasive-action.html)

sevenstrokeroll 12th Feb 2011 19:56

jet/bird evasive action
 
I haven't seen a good discussion on evading bird strikes, especially sucking birds into engines.

I learned to fly at a very ''birdy'' area on the bay of san francisco some 36 years ago. What I learned there wasn't in books.

I offer this:

if you are head on with a formation of birds, bank YOUR plane about 60 degrees, this takes the engines (assuming underwing engines like a 737) out of the plane of the formation of birds...thus saving your engines.

if you are on approach, birds usually dive, so climb.

it is an old wives tale, but if birds are on the runway, you might flip on your wx radar...I've seen flocks of birds takeoff the instant the radar has been turned on.

provide ''bird'' reports to atc for general dissemination.

watch out for birds just above an overcast as you pop out on climb, or just below the undercast as you pop out below!

good luck

Machinbird 12th Feb 2011 21:55

To add to sevenstroke's excellent points:
For a jet aircraft, there is a tiny spot in the middle of your windscreen that all relevant birds are going to appear out of. Figure out where your spot is and give that spot extra attention while in high probability bird territory. By the time you see birds using an aircraft detection and avoidance type scan, it is probably too late to influence the outcome.

And if you see the specks in the distance, you don't need to ID them before taking avoidance.:}

aviatorhi 12th Feb 2011 21:57

Unless you have JT8Ds slung on your airplane, then you can plow through anything. :ok:

Old Fella 13th Feb 2011 00:15

Unless you have JT8D's
 
Aviatorhi This may change your mind.




File:JT8D Engine after Bird Strike.jpg - Wikipedia, the free encyclopedia

aviatorhi 13th Feb 2011 00:46

I've seen tons of pictures of JT8s after bird strikes and that's not the worst of it, I've been ondboard when weve plowed through them as well, in no instance has an engine stopped running.

sevenstrokeroll 13th Feb 2011 02:42

and a JT8D on the back, like a DC9 is even better! :-)

excellent point about the ''spot" on the windshield...good job Machinbird...RU near chicago?

aviatorhi 13th Feb 2011 02:59

727 in my case, but yes, same concept.

In my experience birds usually show up at times when there are more pressing issues to worry about. I remember one showing up right after Vr (before V2) and in situations like that all you can (and should) really do is fly the plane and not even worry about "evading" the thing, too low on airspeed, too close to the ground etc. etc. to be doing unplanned maneuvers. Once you're up and off it's up to the pilot (captain) what they want to do. I've seen people try to evade the big ones only hit them anyway (Abatross) while the small ones hit before you can react (Swallows, with or without coconuts).

sevenstrokeroll 13th Feb 2011 03:42

fine points...especially about swallows with cocoanuts.

you do what you can...I was thinking of the sully flight...if he was flying a dc9 or 727 he would have been on time to charlotte. also using the bank technique might have kept one of the engines out of the bird zone

but if you are at V1...its a tough place to be

sevenstrokeroll 28th Feb 2011 01:20

thanks everyone for your great points.

I just wish someone ''in charge'' would actually look into evasive action techniques for jet airliners. Seems a shame we really don't know too much more than we did before sully's landing.

but if you have a flock of birds in your window...try the bank!

Centaurus 28th Feb 2011 02:02

Flocks of birds seen on the runway can be lethal and the decision to abort or press on becomes a critical choice. Well below V1 is not a problem but depending on surface conditions and length of runway an abort can produce it's own hazards especially in jet aircraft.
In another life I lined up at Edinburgh RAAF, South Australia, runway. It was a long runway and there had been recent heavy rain which had cleared. I was flying a RAAF Viscount. We could see flocks of sea gulls on the runway pecking away at thousands of what seemed to be tiny worms.

We asked ATC to have the duty fire tender to squirt water at the sea gulls (after all that is how rioting crowds in some countries are dispersed). The sea gulls didn't like this too much and flocked off.

Shortly before V1 we observed a mass of sea gulls getting airborne from the grass adjoining the runway and it was clear we were going to run into them as they flew across the runway at cockpit height. We aborted the take off at the same time we felt numerous bird strikes and due to the long runway we stayed off the brakes and coasted to stop using the full length. We saw no point in risking hot brakes when excess runway was available. The ground fine position of the props was very effective at high speed.

There was hardly any damage to the aircraft despite about 25 dead seagulls being found by the fire tender crew.

sevenstrokeroll 28th Feb 2011 02:08

centaurus...good story...good decision. wise use of flat pitch instead of wheel brakes.

TAAMGuy 28th Feb 2011 14:54

Not to diminish the gravity of the topic, but it reminds me of a funny that I heard some years ago. I was an ATC at the time and an arrival reported passing a flock of birds on the approach. I asked the pilot what direction they were travelling so I could inform other traffic. The pilots response was "Some were going up and some were going down!" Thought that was pretty humurous! :p

Canuckbirdstrike 28th Feb 2011 17:22

Sevenstrokeroll, mcuh of what you discuss is in print. Go to the Transport Canada website:

Wildlife Control - Transport Canada

Specifically, read "Sharing the Skies" and you will find lots of factual information on the subject.

As for the suggestion of a large bank angle as a countermeasure for an encounter with a flock of bird, I suggest the outcome is not known. Assuming migratory birds will behave in a consistent manner when startled/threatened is foolhardy. Further, the high bank angle and damage to an engine or flight controls is a recipe for a disaster. A better strategy is to trade speed for energy and climb.

sevenstrokeroll 28th Feb 2011 19:48

I'll have to read that stuff from transport canada.

in the US we don't have any bird training!

the climb is a good maneuver too. my bank thing takes into account the chance that you are descending or unable to climb due to traffic. certainly climbing is an option not to be over looked.

I do think banking the plane and ending up with an engine out isn't terribly dangerous...certainly something to get your attention though. climbing reduced options sometimes too.

just trying to spur conversation on something we don't cover all the time.

EW73 28th Feb 2011 21:51

Similar experience to Centaurus...on the same runway!

I was just at touchdown on RAAF Edinburgh runway 18, in a P3 and a flock of seagulls suddenly appeared from the right, and we went right thru them.

Those large paddles at low airspeed flight idle really cleared the way, sustained no engine damage at all, just a whole heap of birds tangled in the gear.

Though, in all my years of flying P3s at all sorts of very low altitudes, down to 30 feet RA on more than one occasion, and with numerous times flying around 300 feet along beaches for some distance, and especially investigating illegal fishing boats (with the associated giant flocks of birds in their immediate vicinity)...

I found that the birds always dived when approached by our aircraft, some left, some right, but always down...so it was a standard maneuver to climb when faced with unexpected (as they always were!) birds.
In 5,600 hours on P3s in this environment, I never had a birdstrike that did any real damage, I was lucky!

EW73 :)

sevenstrokeroll 28th Feb 2011 22:28

EW73

I agree with you. In my first post I mentioned that birds always dive and that climbing is a good maneuver if available.

my first plane ride was in 1963 in the P3's brother, the Lockheed 188 Electra....the only way to fly!

I seem to recall that an Eastern airlines Electra sucked starlings at Boston and went down.

thanks for coming to this thread.

Chris Scott 28th Feb 2011 23:11

Nice one, sevenstrokeroll, but no one has raised the issue of lighting. To be visible to the birds must be important (they're not stupid), but are daytime landing lights a help or hinderance? And how about turn-off lights only (not available in flight on the A320 family)?

sevenstrokeroll 28th Feb 2011 23:45

interesting chris...out of habit I always have all lights on for takeoff and landing and below Positive Control Airspace (FL180 in usa). (fog and odd vis situations aside).

its too bad that A320 can't put all lights on in flight.

misd-agin 28th Feb 2011 23:47

Birds tend to tuck and dive. Not 'always'. However, they also underestimate the closure rate of 150-350 MPH, so they actually gain little vertical seperation.

60 degrees of bank? First time I've heard that one, especially in an airliner.

Can we be drug tested for posting on MB's?

Canuckbirdstrike 1st Mar 2011 21:32

Lights are beneficial at increasing aircraft visibility. Radar does nothing. The challenge we face is that new aircraft engines are quiet which removes one other bird sensory mechanism for detecting aircraft.

I still do not support the bank angle method for mitigating possible bird strike damage to engines. Climbing will work, and you do not need to climb much at all even 150 feet will work. think of it like a TCAS climb maneuver.

I must fully support reporting of bird activity. I have been very active in bird strike safety work for many years and I cannot begin to describe how frustrating it is to hear of another serious bird strike event where either the operating crew, other pilots or other people saw the birds and did not report them.

US Air 1549 had a great outcome - no serious injuries or death. The next time may not be that way. There will be a next time and sooner than we think. The next round of migratory movements are already starting and in many urban centers waterfowl are resident.


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