Birdstrikes - incl pictures
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VFRPilotpb, milspec in reality means little. The windshield in a B206 is identical to that in the OH58, or at least the original models. And it's not even close to birdproof. I've seen several that were shattered by seagulls and smaller species. I've hit lots of birds, including at least half a dozen seagulls, but fortunately none of them in the windows. I have disintegrated them with the main rotor, partially disabled them, and had one come down through the main rotor blades at idle completely untouched. One of the scarier bird sightings happened at about 2AM on a very dark night. A goose came by, missing the left windshield by about 2 feet. Fortunately, I was in the right seat at the time. ;-) That goose would have caused lots of damage, and possibly killed anyone behind the windshield that it hit. Where it was going at that time of night I have no idea, but I don't ever want to see it again.
Peter, there have been a few Army birdstikes on Army gazelles over the years, where birds as big as buzzards have entered the cockpit. As other posters have mentioned, it's not necessarily the damage to the perspex, but whether you get a face full of feathers. All the more reason to wear a helmet with the visor down.
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Birdstrike?
Several years ago whilst on exercise in Germany one of our Scout AH Mk1 aircraft landed at the HLS which was located just outside a village near the East German border. After it landed and the aircraft shut down I noticed the Pilot get out and go down on his hands and knees inspecting the underside of the aircraft. I walked across and asked the Pilot, an Artillery Officer, what the problem was to which he replied “I think I have had a bird strike on the ARC 340 aerial ASM.” I got down and sure enough the aerial was pushed back up into the tail boom. My reply was “It must have been a really low flying bird Sir”. “Why do you say that ASM?” was the response. “Well the aerial is covered in mud, you didn’t by any chance land in a ploughed field at your last location?” Exit a rather red faced Pilot.
Several years ago whilst on exercise in Germany one of our Scout AH Mk1 aircraft landed at the HLS which was located just outside a village near the East German border. After it landed and the aircraft shut down I noticed the Pilot get out and go down on his hands and knees inspecting the underside of the aircraft. I walked across and asked the Pilot, an Artillery Officer, what the problem was to which he replied “I think I have had a bird strike on the ARC 340 aerial ASM.” I got down and sure enough the aerial was pushed back up into the tail boom. My reply was “It must have been a really low flying bird Sir”. “Why do you say that ASM?” was the response. “Well the aerial is covered in mud, you didn’t by any chance land in a ploughed field at your last location?” Exit a rather red faced Pilot.
Nick
I thought I was somewhat safe behind the heated glass windshield in the S76!!! Have there not been any bird stike test on the windshield at all? I thought I have read about this, but you would know I'll guess.
I have once tried to break a replaced fatigue cracked S76 windshild by jumping on it laying convex on the floor with my humble weight
but that piece of glass won that fight
so it must be tougher than me....
I thought I was somewhat safe behind the heated glass windshield in the S76!!! Have there not been any bird stike test on the windshield at all? I thought I have read about this, but you would know I'll guess.
I have once tried to break a replaced fatigue cracked S76 windshild by jumping on it laying convex on the floor with my humble weight
but that piece of glass won that fight so it must be tougher than me....
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Collective bias,
I recall that we did bird strike the windshield, but do not recall the criteria. I will check. It was to meet the BCAR, I think. g33 had it right, I'll bet.
I recall that we did bird strike the windshield, but do not recall the criteria. I will check. It was to meet the BCAR, I think. g33 had it right, I'll bet.
Hey Helo Wife!
I recognise the ugly pusses of DG in the middle and N McC on the right, but who was on the left? PM me if you wish!
And I suppose Cormorant a l'Orange doesn't really cut it as a 9 Sqn in-flight lunch either...
I recognise the ugly pusses of DG in the middle and N McC on the right, but who was on the left? PM me if you wish!
And I suppose Cormorant a l'Orange doesn't really cut it as a 9 Sqn in-flight lunch either...
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Ascend Charlie - the handsome chap on the left is my husband - and of course he hasn't changed a bit!
It was a 5 Sqn venture and perhaps that explains why you don't recognise him.
It was a 5 Sqn venture and perhaps that explains why you don't recognise him.
I personnaly prefer glass windscreen, and our old S76 A++ are equipped with them, but now, on our new S76C+ it's plexiglass...
I think that, the silver brains who have decided these aircrafts customomization have mainly considered the windscreen deicing, maybe weight ,and forgotten the bird strike hazard, despite numerous occurences.
I think that, the silver brains who have decided these aircrafts customomization have mainly considered the windscreen deicing, maybe weight ,and forgotten the bird strike hazard, despite numerous occurences.
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Nick,
BCAR 29 required the windscreen to withstand a 1.8 kg bird.
BCAR Part G which applied to the S76 many years ago required a 2 lb bird (0.9 kg).
So the latest standards in FAR/JAR 29 of a 1 kg bird is not a big step forward and is in fact a big backward step for the UK.
Have you tested the S92's windscreen to destruction? Will it take much more than 1 kg?
g33
BCAR 29 required the windscreen to withstand a 1.8 kg bird.
BCAR Part G which applied to the S76 many years ago required a 2 lb bird (0.9 kg).
So the latest standards in FAR/JAR 29 of a 1 kg bird is not a big step forward and is in fact a big backward step for the UK.
Have you tested the S92's windscreen to destruction? Will it take much more than 1 kg?
g33
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G33,
I guess there is some static on this internet, because you continue to think that a 1.8KG bird protection for the windscreen ONLY, and an otherwise totally unprotected aircraft is somehow better than an aircraft that has total protection of the entire aircraft, including rotors, controls covers, driveshaft covers and the like. Even though documented data says that 85% of birdstrikes occur on places other than the windscreen!
Where did we go wrong here? Am I missing something about your logic?
I guess there is some static on this internet, because you continue to think that a 1.8KG bird protection for the windscreen ONLY, and an otherwise totally unprotected aircraft is somehow better than an aircraft that has total protection of the entire aircraft, including rotors, controls covers, driveshaft covers and the like. Even though documented data says that 85% of birdstrikes occur on places other than the windscreen!
Where did we go wrong here? Am I missing something about your logic?
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Nick,
There may be some static as you didn't answer my last question.
Some other areas of the helicopter were required to be tested under BCAR 29 and DGAC Special Conditions, the main area which was not tested was the tail rotor, but the head and engine intakes were. I agree that requiring a full aircraft test is an improvement, but a 1 kg impact on the windscreen is too low based on my practical experience of birdstrikes.
If we take your figures: 85% of birdstrikes occur elsewhere, so 15% occur on the windscreen. You said that a 1 kg bird is the 95th centile, then 0.75% (15% x 5%) of birdstrikes at Vh could penetrate the windscreen if it is only capable to withstanding a 1 kg impact. The probability of getting a bird in your face is starting to look higher than the probability of other major emergencies. This problem could be getting worse as the new types coming onto the market, S92, EC 225, EC 155B1 and AB 139 cruise around at a high speed close to Vh.
You said that a 1 kg bird was the cutoff between safety and practicality, I am not convinced.
g33
There may be some static as you didn't answer my last question.
Some other areas of the helicopter were required to be tested under BCAR 29 and DGAC Special Conditions, the main area which was not tested was the tail rotor, but the head and engine intakes were. I agree that requiring a full aircraft test is an improvement, but a 1 kg impact on the windscreen is too low based on my practical experience of birdstrikes.
If we take your figures: 85% of birdstrikes occur elsewhere, so 15% occur on the windscreen. You said that a 1 kg bird is the 95th centile, then 0.75% (15% x 5%) of birdstrikes at Vh could penetrate the windscreen if it is only capable to withstanding a 1 kg impact. The probability of getting a bird in your face is starting to look higher than the probability of other major emergencies. This problem could be getting worse as the new types coming onto the market, S92, EC 225, EC 155B1 and AB 139 cruise around at a high speed close to Vh.
You said that a 1 kg bird was the cutoff between safety and practicality, I am not convinced.
g33
Avoid imitations
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Nick, G33, I think we should get a third opinion from a relevant point of view. Anyone considered what the poor birds think about this? 
Senis Semper Fidelis
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Hey you chaps,
Those of you who are from the Pro side of Heli flying are putting in some very straight and well written answers to what I thought was a pretty simple question, but the more I read from your explanations the more it seems a Bird strike on the windsheild is not the only problem,
Nick, if I understand your answers correctly a well aimed beak hitting your rear pylon, or your Rotor head whilst at cruise would have a equally disasterous outcome and a bad end to your day.
Not long ago I had a surprise meeting with a Cock Pheasant, on one our local Motorways the nominal weight for one of these birds is about 2 to 2.5 Lbs so around 1 Kilo plus, I think I was getting along at about 80/85 mph and was passing two inner lanes of traffic the bird came into my left vision hit and was gone as fast as you have read these few words, it destroyed my windscreen and removed the drivers side wing mirror now then if that can happen to a vehicle it must be like a bomb going off when the same sort of bird weight flys into a heli.
Those of you who are from the Pro side of Heli flying are putting in some very straight and well written answers to what I thought was a pretty simple question, but the more I read from your explanations the more it seems a Bird strike on the windsheild is not the only problem,
Nick, if I understand your answers correctly a well aimed beak hitting your rear pylon, or your Rotor head whilst at cruise would have a equally disasterous outcome and a bad end to your day.
Not long ago I had a surprise meeting with a Cock Pheasant, on one our local Motorways the nominal weight for one of these birds is about 2 to 2.5 Lbs so around 1 Kilo plus, I think I was getting along at about 80/85 mph and was passing two inner lanes of traffic the bird came into my left vision hit and was gone as fast as you have read these few words, it destroyed my windscreen and removed the drivers side wing mirror now then if that can happen to a vehicle it must be like a bomb going off when the same sort of bird weight flys into a heli.
Nick
Thanks for getting back on the S76 issue. I feel at ease now when I now there is at least windshield protection.
Was that test with the heat on or not, and if not, have it been tested with the heat on to see how nuch diffrence it makes?
On fixwing there is a recommendation on a number of aircrafts to have the heat on in low pwr during TO and landing to better the protection.
Thanks for getting back on the S76 issue. I feel at ease now when I now there is at least windshield protection.
Was that test with the heat on or not, and if not, have it been tested with the heat on to see how nuch diffrence it makes?
On fixwing there is a recommendation on a number of aircrafts to have the heat on in low pwr during TO and landing to better the protection.
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collectivebias,
The strike is assumed to take place at the worst condition, heat and outside air temperature both. The strength is actually not just a pure tensile strength issue, as bending and bowing of the windshield actually helps it catch the bird without breaking. The worst place for the hit is at the edge, where the windshield is rigidly restrained, so it tends to rip. At the center, a much higher energy impact can be restrained.
cpt,
Fear not, the windshield's strength comes from the acrylic, the glass is only there for scratch resistance. The plexi windshield is just as strong!
g33,
You willingness to completely ignore the other 85% of the aircraft, and zoom your microscope in on the windshield is impressive! Your math is less so, but who has time to debate? You obviously believe that a given helo with purely windshield protection to absorb a 1.8KG bird (at unknown speed) is superior to one that offers full helo protection of all rotors, shafting, windshield, engines and controls covers to a 1 KG bird is now known.
Unfortunately for you, about 100 expert government regulators in about 40 countries do not share your opinion, so those of us flying new transport helicopters will be better protected than your proclivities would dictate. I suggest that you relax behind your thicker windshield, and practice tail and main rotor failure emergencies.
The strike is assumed to take place at the worst condition, heat and outside air temperature both. The strength is actually not just a pure tensile strength issue, as bending and bowing of the windshield actually helps it catch the bird without breaking. The worst place for the hit is at the edge, where the windshield is rigidly restrained, so it tends to rip. At the center, a much higher energy impact can be restrained.
cpt,
Fear not, the windshield's strength comes from the acrylic, the glass is only there for scratch resistance. The plexi windshield is just as strong!
g33,
You willingness to completely ignore the other 85% of the aircraft, and zoom your microscope in on the windshield is impressive! Your math is less so, but who has time to debate? You obviously believe that a given helo with purely windshield protection to absorb a 1.8KG bird (at unknown speed) is superior to one that offers full helo protection of all rotors, shafting, windshield, engines and controls covers to a 1 KG bird is now known.
Unfortunately for you, about 100 expert government regulators in about 40 countries do not share your opinion, so those of us flying new transport helicopters will be better protected than your proclivities would dictate. I suggest that you relax behind your thicker windshield, and practice tail and main rotor failure emergencies.
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Nick,
As I said in my last post, I agree that covering the whole aircraft is better than just certain parts, so I am not ignoring the rest of the aircraft, merely trying to ascertain from a highly regarded test pilot if he thinks that 1 kg at Vne or Vh is sufficient. As someone who has had birds enter my cockpit through the windscreen the topic is dear to my heart.
We all know, especially in Europe, that when regulations are harmonised the lowest common dominator tends to be applied, so I am not surprised that 1 kg was used.
Do I detect the old approach of "attack is the best form of defence", as you still have not answered my questions about the S92. By the way, congratulations to you and the rest at Sikorsky for winning the Canadian Sea King replacement contract.
g33
As I said in my last post, I agree that covering the whole aircraft is better than just certain parts, so I am not ignoring the rest of the aircraft, merely trying to ascertain from a highly regarded test pilot if he thinks that 1 kg at Vne or Vh is sufficient. As someone who has had birds enter my cockpit through the windscreen the topic is dear to my heart.
We all know, especially in Europe, that when regulations are harmonised the lowest common dominator tends to be applied, so I am not surprised that 1 kg was used.
Do I detect the old approach of "attack is the best form of defence", as you still have not answered my questions about the S92. By the way, congratulations to you and the rest at Sikorsky for winning the Canadian Sea King replacement contract.
g33
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g33,
regarding your question, "have you tested the windshield to destruction" the answer is no. With the strike of the 1 KG bird at 165 knots, the worst place is at a corner, and test failure is any penetration of any kind (a morsle of bird is failure). The windshield kept out everything, and at the worst place. If one were to speculate, a bigger bird at cruise speed (more like 150 knots) and that strikes the windshield in the center would possibly not penetrate. By 120 knots or so, protection is assured for the 1.8 KG bird, with zero penetration in the worst place.
The effects of the bird on the tail rotor are eye-watering. a 1 KG bird on the tail rotor will fail the blade at the root on every helicopter below about 35,000 lbs, unless they were specifically designed to withstand the shock. The energy of the bird on the main and tail tips is about 40,000 ft-lb, about the same as an A-10's cannon projectile on a tank! I wandered through the NTSB data base the other day and found three helos that crashed due to bird strikes on the tail rotor alone, and several more with birds on the main rotor that caused severe vibration.
I have posted an avi film of the S/H-92 tail rotor bird strike tests, it is about 900K, so be patient. It shows the tail rotor running in a bird stand, and red jelly globules are being tossed at it at 165 knots, followed by some pheasants:
http://www.s-92heliport.com/BIRD1.AVI
Here is a very short clip of the bird hitting the top of the windshield(upside down view!). It is 1 second because it is high res, so it is still 1.5 megs!:
http://www.s-92heliport.com/Bird2.avi
regarding your question, "have you tested the windshield to destruction" the answer is no. With the strike of the 1 KG bird at 165 knots, the worst place is at a corner, and test failure is any penetration of any kind (a morsle of bird is failure). The windshield kept out everything, and at the worst place. If one were to speculate, a bigger bird at cruise speed (more like 150 knots) and that strikes the windshield in the center would possibly not penetrate. By 120 knots or so, protection is assured for the 1.8 KG bird, with zero penetration in the worst place.
The effects of the bird on the tail rotor are eye-watering. a 1 KG bird on the tail rotor will fail the blade at the root on every helicopter below about 35,000 lbs, unless they were specifically designed to withstand the shock. The energy of the bird on the main and tail tips is about 40,000 ft-lb, about the same as an A-10's cannon projectile on a tank! I wandered through the NTSB data base the other day and found three helos that crashed due to bird strikes on the tail rotor alone, and several more with birds on the main rotor that caused severe vibration.
I have posted an avi film of the S/H-92 tail rotor bird strike tests, it is about 900K, so be patient. It shows the tail rotor running in a bird stand, and red jelly globules are being tossed at it at 165 knots, followed by some pheasants:
http://www.s-92heliport.com/BIRD1.AVI
Here is a very short clip of the bird hitting the top of the windshield(upside down view!). It is 1 second because it is high res, so it is still 1.5 megs!:
http://www.s-92heliport.com/Bird2.avi
Last edited by NickLappos; 24th Jul 2004 at 15:51.