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-   -   Bird Strike (https://www.pprune.org/tech-log/68560-bird-strike.html)

RatherBeFlying 15th Nov 2005 23:41

Always wondered what microwaved swan would be like:}

ColumbiaStudent 3rd Dec 2005 03:40

I'm writing a story on bird strikes for my journalism class at Columbia. Are there any commercial pilots out there who'd be willing to share their story with me? I prefer to speak with someone who had a bird strike experience in or out of JFK or can point me to someone who did. Thanks for your help.

ssg 7th Dec 2005 15:34

Bird Strikes
 
I tend to agree that while it's possible to hit a bird up high, maybe him being caught in an updraft, t storm, who knows, it's more likely that damage was done earlier.

Maybe a nick on a blade, that eventualy came apart, ect.

On a funny note, in the Mojave, they send chickens and turkeys through engines to test just this fact, on how they would affect an engine.

I am curious if anyone has any luck turning up the radar to get birds to move off the runway, never helped me, it doesn't move a herd of Elk either. :)

SSG

jumpseater 7th Dec 2005 15:41

I've been doing some work on the issue, I have records of crew reports of 57 strikes above 3,000ft in a two year period, so they certainly occur, but there are far fewer than those at lower levels, i.e. below 3,000ft.

CS
pm me, with some details of what you're doing, I may be able to assist
rgds
js

Centaurus 10th Dec 2005 11:48

One thing for sure. Maintaining 250 knots below 10,000 ft goes a long way to improving your chances of surviving a big bird hit on the windscreen. In Australia and Pacific Islands, it is normal for jets to ignore the dangers of high speed bird strike risk and they will deliberately climb/descend at 300 knots + below 10,000 ft. I have seen 737's level at 1500 ft over the sea at 300 knots ignoring the sea gull hazard. A most courageous decision...

A bird strike on the windscreen at those speeds risks windscreen shatter and crew injuries. That is why on some jets it is SOP to limit speed to 250 knots below 10,000 ft with windscreen heat inoperative, in recognition of the potential disastrous consequences of high speed bird strike.

compressor stall 10th Dec 2005 13:30

birds on weather radar
 
Many years ago, flying a VFR lightie across Melbourne was told that there was unidentified traffic crossing right to left at three miles.

Turned out to be a flock of geese, and the often metal tags on birds were causing the return.

Presumably, weather radar would pick up such a return, if the bird had one on (and if you had the wx radar on, and were watching it).

Canuckbirdstrike 11th Dec 2005 14:22

OK, once again the issue of using WX radar as a bird deterrent is raised and the answer is still the same - does not work!

Now the issue of bird strikes and altitudes..... A very interesting subject that requires careful analysis. Indeed, I authored a report for Transport Canada on this very subject in September 2002. I completed an in-depth risk analysis of operations at speed greater than 250 knots above 3,000 ft. AGL. the analysis was most revealing. I will check and see if I am able to make the report or sections of it available for all to read.

The critical point is that while the number of strikes may be lower, at higher altitudes, the size and number of birds (tend to be large flocking birds), the fact that these bird species populations and mean weights are increasing dramatically, the fact that as altitude increases at a fixed IAS the TAS increases, and certification standards a are based on a 4 lb bird at Vc at sea level is a recipe for disaster. When you look at this you see very rapidly that any larger bird at higher speed can and will exceed the certified impact force that the windscreen or aircraft structures were designed for.

What is even more interesting is when you look at the acceleration from 250 knots to 300+ knots. The rate of climb during acceleration is typically half the rate of climb for a steady state speed climb. This results in doubling the exposure and probability of striking a bird in the high risk altitudes. Couple this with the fact that the impact force increases as the square of the speed then we have the classic high-risk scenario - increased probability, exposure and severity.

The North American strike data supports this when you analyze the reported damage that these strikes incur vs. the total number of reported strikes.

Lesson learned - high-speed flight below 10,000 ft is a high risk activity that can exceed the certification standard of the aircraft and with the advent of more twin-engine aircraft and the increasing high-risk bird species populations the risk is increasing.

Richard

ssg 19th Dec 2005 17:20

Geese
 
In the states, I smack birds all the time, generaly on approach.
I think it goes with out saying that hitting a bird at 100 knots is better then 300 kts.

-SSG


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