Birdstrikes
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Well of course bats are mammals not birds. I can also assure you that there is no scientific data nor is there any reason to believe that bats can detect weather radar. Bats use echo location with sound, just at a frequency that we cannot detect. Therefore turning on the radar has no effect. Unfortunately, the urban legend of turning on radar to "scare away" birds has permeated our industry and therefore there are still many companies and airports that put references to it in their SOP's.
As an aside bat strikes are not that uncommon. as for mammal strikes in general there are lots of them. In North America the most comonly struck mammals are deer. Around the world there are all kinds of unusual things struck by aircraft including fish, cows, turtles and the list goes on.
As an aside bat strikes are not that uncommon. as for mammal strikes in general there are lots of them. In North America the most comonly struck mammals are deer. Around the world there are all kinds of unusual things struck by aircraft including fish, cows, turtles and the list goes on.
Bats are typically struck when they come out of their caves at night to feed.
I can't recall any other crew reported bat strikes except in that time window. Of course like most strikes (birds or bats) they are not associated with symptoms to the crew. Also in most cases even the ground examinations wouldn't be able to tell the difference between a big bug or a bat strike.
I can't recall any other crew reported bat strikes except in that time window. Of course like most strikes (birds or bats) they are not associated with symptoms to the crew. Also in most cases even the ground examinations wouldn't be able to tell the difference between a big bug or a bat strike.
Join Date: Jul 2005
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I flew the 146 for some 5 years. So many bird strikes that the Ops people caled me a chick magnet, and they weren't being complementary.
In the 2 and a bit years I've flown the 717, I've only experienced one bird strike. The ports, routes, and times are constant between the two types.
I'd be interested in any theory as to why the 717 has been significantly less prone to bird strike.
In the 2 and a bit years I've flown the 717, I've only experienced one bird strike. The ports, routes, and times are constant between the two types.
I'd be interested in any theory as to why the 717 has been significantly less prone to bird strike.
On the 146 were the bird strikes on the nose of the aircraft or did some fly into the back..
Have been told the 146 is the only aircraft you check both ends or the aeroplane for birdstrikes..
To add, On many aircraft the radar fires up on engine start.eg 737 NG A330etc in PWS mode so unless switched to off it will be running anyway
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Just remember that impact force goes up with the square of speed and that the certification standard is for a "single 4 lb bird" and the aircraft will be able to "continue for a safe landing". Add to this that above 1,000 ft. AGL you are most likely to be hitting larger birds such as raptors and waterfowl and you have a recipe for a disaster. Oh, and the last point is that with only tw exceptions all the large bird populations (greater than 4 lbs) are increasing in both numbers and average weight. Also be aware that many of these birds are not migrating long distances as they have done in the past and staying resident.
It is not safe to operate above 250 knots below 10,000 feet. If you do, you are rolling the dice.
It is not safe to operate above 250 knots below 10,000 feet. If you do, you are rolling the dice.
Join Date: Jan 2001
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Cum hoc ergo propter hoc
or, in English, Correlation does not imply Causation.
Two blokes walk down a city street. One notes that his mate has put a banana in his left ear.
"Hey Bob, whats with the banana in your ear?"
"Bill, it keeps away the elephants."
"Bob, there are no elephants in Bourke Street!"
"See Bill - it works!"
If somebody wants to believe something, then sometimes the word of the scientist is not enough!
Two blokes walk down a city street. One notes that his mate has put a banana in his left ear.
"Hey Bob, whats with the banana in your ear?"
"Bill, it keeps away the elephants."
"Bob, there are no elephants in Bourke Street!"
"See Bill - it works!"
If somebody wants to believe something, then sometimes the word of the scientist is not enough!
Last edited by ITCZ; 8th May 2008 at 12:17.
Join Date: Oct 2002
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Well said ITCZ.
Surely depends on the aeroplane? We have a bird speed restriction of 313kts below 8,000ft in the 757 and 767. Rumours are that speed only applies to one type but is used on both for commonality. It can't be THAT dangerous as there aren't loads of crashes happening because of birdstrikes on aircraft faster than 250 knots below 10,000ft. And why 250 knots? Why not 270 or 210 or 237? It seems convenient that the ATC speed restriction is the same as the "safe bird speed limit"?
t is not safe to operate above 250 knots below 10,000 feet. If you do, you are rolling the dice.
Surely depends on the aeroplane? We have a bird speed restriction of 313kts below 8,000ft in the 757 and 767. Rumours are that speed only applies to one type but is used on both for commonality. It can't be THAT dangerous as there aren't loads of crashes happening because of birdstrikes on aircraft faster than 250 knots below 10,000ft. And why 250 knots? Why not 270 or 210 or 237? It seems convenient that the ATC speed restriction is the same as the "safe bird speed limit"?
As such there is no on-off light switch to say that you are safe or unsafe. It's all a matter of probabilities of the combinations..
For current part 25 aircraft, the data suggests that we must be safe enough since it has produced millions of hours of safe flying in the bird filled skies. Sure there have been structural penetrations and even some injuries but only a handful of accidents due to structural failure of the aircraft. Thus the current design criteria (jump this high) responsibly have resulted in an aircraft surviving these in-flight strikes in the 150-250 kt range.
But should there be a meaningful statistical change in the encounter ballistics (number of birds larger than 4 lbs and/or higher aircraft speeds) then the results are going to shift to more accidents per million hours. It's only a question of how many zeros, if any, in front of the numerator.
Like any of our environmental related hazards, it’s the balance between product capability and avoidance tactics that produce our "safe enough" results.
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Of course there is no on/off switch. What I am saying is that flying above 250 knots below 10,000ft is not a statistically significant danger to the aircraft or its occupants in most situations.
Flying near flocks of migratory birds, low over forests in Africa or near thermalling flocks of birds is of course a different story. I just think that saying flying above 250 knots below 10,000ft is rolling the dice is a misleading and not quite correct statement. I see the point though, although I'm happy in most non restricted situations to go blatting along at 290 knots without worrying too much below 10,000ft, in fact it was SOP before the 250 below 10 was introduced to the UK.
Flying near flocks of migratory birds, low over forests in Africa or near thermalling flocks of birds is of course a different story. I just think that saying flying above 250 knots below 10,000ft is rolling the dice is a misleading and not quite correct statement. I see the point though, although I'm happy in most non restricted situations to go blatting along at 290 knots without worrying too much below 10,000ft, in fact it was SOP before the 250 below 10 was introduced to the UK.
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Psychologically, you may feel safer by tuning the Wx radar. But I beleive it is a midwife tale.
Have a look at Venice airport, Italy Jepp 10-9. They instruct the pilots to switch on the Wx radar for take off and landing due to birds in the vicinity. I dont know who gave them this false idea.
Birds have the 5 senses possed by humans (I seem to recall reading somewhere that they hear at same freq as humans)
But who knows for sure other than the birds themselves ?
Have a look at Venice airport, Italy Jepp 10-9. They instruct the pilots to switch on the Wx radar for take off and landing due to birds in the vicinity. I dont know who gave them this false idea.
Birds have the 5 senses possed by humans (I seem to recall reading somewhere that they hear at same freq as humans)
But who knows for sure other than the birds themselves ?
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IIRC some animals (including possibly pigeons) are equipped with a magnetic compass (!) in the form of a separate 'sensor' with a small piece of magnetite, which you could probably classify as a sixth sense.
However, it is equally unaffected by microwaves as the other five senses, so yes, it's a midwife tale.
However, it is equally unaffected by microwaves as the other five senses, so yes, it's a midwife tale.
Beau_Peep
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bird hit actions...
little off the subject, but I thought I share it with you all.. I think it would be a good idea to cross check the airspeed and altitude readings immediately after bird hit, to ensure the bird has not hit one of the probes...
say what?
say what?
Join Date: Jan 2005
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Since this IS TechLog, may I ask a question?
Large flocks of birds DO show up on radar. IIRC ground-based meteo-type radars are even used regularly to follow bird migration.
So my question is: what's the minimum range setting on a typical aircraft Wx radar? And is that setting ever used at lower levels?
It will never catch that one heron just after take-off. But it might just catch that huge flock of Canada Geese at 5000 ft, or the vultures at 10,000 ft...
I'm only a radar geek. I just wondered.
CJ
Large flocks of birds DO show up on radar. IIRC ground-based meteo-type radars are even used regularly to follow bird migration.
So my question is: what's the minimum range setting on a typical aircraft Wx radar? And is that setting ever used at lower levels?
It will never catch that one heron just after take-off. But it might just catch that huge flock of Canada Geese at 5000 ft, or the vultures at 10,000 ft...
I'm only a radar geek. I just wondered.
CJ
Bottums Up
Originally Posted by Remote Diagnostic
I would say that the engine position makes the difference.
