jet/bird evasive action
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certainly transports should only rarely exceed 25-30 degrees of bank...but they, and I would like to think most ATP's, are capable of that.
if your plane can't handle a 60 degree bank...better find a new plane!
you might not even get to 60 degrees of bank while attempting to move your engines out of the plane of the bird formation...but it is an idea when other maneuvers are not suitable.
if your plane can't handle a 60 degree bank...better find a new plane!
you might not even get to 60 degrees of bank while attempting to move your engines out of the plane of the bird formation...but it is an idea when other maneuvers are not suitable.
The perception that statistically this is not a risk is a flawed argument for two reason; first the data just does not support the assertion and second risk needs to be assessed using the matrix or exposure probability and severity and the use of data to solely assess risk is a flawed methodology.
There also needs to be an understanding of the aircraft certification requirements for bird strikes; engine and airframe. If we confine the discussion to airline category, jet powered aircraft, which have the highest requirements, there are deficiencies in the requirements that are no starting to be discussed.
One of the key deficiencies is the lack of a requirement to consider damage to more than one engine.
The next is that there is no requirement to consider damage to the aircraft AND the engine(s) at the same time.
Accident and incident reports are clearly showing that this is occurring and at a rate that is worthy of design consideration.
There also needs to be an understanding of the aircraft certification requirements for bird strikes; engine and airframe. If we confine the discussion to airline category, jet powered aircraft, which have the highest requirements, there are deficiencies in the requirements that are no starting to be discussed.
One of the key deficiencies is the lack of a requirement to consider damage to more than one engine.
The next is that there is no requirement to consider damage to the aircraft AND the engine(s) at the same time.
Accident and incident reports are clearly showing that this is occurring and at a rate that is worthy of design consideration.
There are many factors combining together that establish risk and to selectively cite some while excluding others is also not statistically valid.
Yes even I am guilty of that in the desire to KISS the subject as posted (unplaned manuevers as an escape from a historic risk)
It is also true that the regulations do not cover all possible combinations of birds, engines and aircraft systems. That is the nature of how regulations are developed for varriable enviromental threats. Thus the regulation and design intent is to take into account how often really bad stuff has occured in the past and to provide a modicum of capability within a balance of avoidance. There are many other risks to flight safety which are competing for attention at any given time so the intention of evaluating changes to our response is necesarily proritized towards the low hanging fruit on the tree.
Keeping with this ideal, any of us can put forth new ideas for addressing the risk and then evaluating how much benefit we can expect vs introducing some unknown new risk.
I'm open to suggestions for such risk reduction within the confines of this thread subject or even expansion if so stated
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do we think it is safe to say that the high bypass fans /engines are more susceptible by their nature to sucking bigger birds?
my first jet (NA 254-40) had small inlet engines and a nice cross of metal (if you will) that would easily slice a bird up coming in to the fan/compressor section.
the JT8D as we have talked about has such a small inlet compared to the CFM<56.
etc.
my first jet (NA 254-40) had small inlet engines and a nice cross of metal (if you will) that would easily slice a bird up coming in to the fan/compressor section.
the JT8D as we have talked about has such a small inlet compared to the CFM<56.
etc.
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...you might not even get to 60 degrees of bank while attempting to move your engines out of the plane of the bird formation...but it is an idea when other maneuvers are not suitable.
Imagine, being on the ILS (in good weather) at LAX on 25L, with another jet on a visual at the same time on 25R (wing tip to wing tip) and our intrepid pilot on the ILS on 25L...decides he needs to maneuver to avoid birds...at 900 agl...off to the right.
BANG.
It's all over, except for the post mortim on the dead bodies.
Sorry, sevenstrokeroll, you might be a nice guy and all, but....very poorly thought out with a big jet airplane.
NB.
And yes, I've been wing tip to wing tip at at LAX...on the 25's...with a 707.
DC-8 opposite.
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Lomapaseo, valid points, but there is already activity in the industry on the issue of bird strike certification standards not being adequate.
I have considerable experience working in the regulatory environment and fully appreciate the parameters that drive regulatory change.
Sadly, rather than really understanding the US Air 1549 event and making meaningful changes to airport wildlife control requirements, training for the industry and revising certification standards, we continue to ignore what the data and risk assessments are telling us.
I fear that the only way this issue will get the traction it needs is a tombstone safety event with lots of casualties. we have not had one in recent memory and US Air 1549 only became a book and a movie (pardon the sarcasm).
Curiously no mention of the Ryanair event in Rome the November before US Air 1549 is made. Another double engine failure from birds with another successful outcome. There are many other disturbing incidents, the frequency of which is increasing.
How long do you want to keep rolling the dice........
I have considerable experience working in the regulatory environment and fully appreciate the parameters that drive regulatory change.
Sadly, rather than really understanding the US Air 1549 event and making meaningful changes to airport wildlife control requirements, training for the industry and revising certification standards, we continue to ignore what the data and risk assessments are telling us.
I fear that the only way this issue will get the traction it needs is a tombstone safety event with lots of casualties. we have not had one in recent memory and US Air 1549 only became a book and a movie (pardon the sarcasm).
Curiously no mention of the Ryanair event in Rome the November before US Air 1549 is made. Another double engine failure from birds with another successful outcome. There are many other disturbing incidents, the frequency of which is increasing.
How long do you want to keep rolling the dice........
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411A
you missed the boat. I offered the bank as an escape maneuver when other options wouldn't work...imagine if that 707 was over your head and you pulled up to avoid the birds...and now you both have TCAS and it issues an escape maneuver.
a pilot needs many things in his bag of tricks and I was offering a new one to consider.
KLAX, KSFO...lots of airports are side by's.
you missed the boat. I offered the bank as an escape maneuver when other options wouldn't work...imagine if that 707 was over your head and you pulled up to avoid the birds...and now you both have TCAS and it issues an escape maneuver.
a pilot needs many things in his bag of tricks and I was offering a new one to consider.
KLAX, KSFO...lots of airports are side by's.
How long do you want to keep rolling the dice........
The world is imperfect, always was and always will be.
Rolling dice is just one of the imputs that we use in a monte carlo stastical system to prioritize what we work on. Of course such a system needs data but nobody intends to wait and count enough tombstones. Thus the pointer data is at a level of risk where no lives are lost since critical factors being missing or something worked as planned (pilot training etc.)
The regulations need to keep up with measured changes either via mother nature, operation or product capability. Since the data to support such changes as well as expert manpower is available these regulatory changes will keep on being updated every 5 years until /unless ignored shortfalls in other areas capture the attention of the I told you sos.
I sense that the work on the engine side of the regulatory function will soon make it more likiely that multiple bird strikes on the aircraft as well will combine with the engine side of the systems and result in accidents. There is already data available in this arena.
do we think it is safe to say that the high bypass fans /engines are more susceptible by their nature to sucking bigger birds?
However the bottom line is the capability to operate in a natural environment and that brings into play the susceptibility to critical damage.
Keep in mind in the transport side of things the birds are not inantimate objects but will take some kind of evasive action albeit not always the safest zig and zag. Couple this with the change in dynamics to the engine blading if the bird happens to intersect a solid structure on the way into the engine and turn itself into much smaller pieces (Hudson River).
The idea behind the regulation is to provide a relatively flat field of risk accross the various engine sizes and types else by hit or miss we would just regulate out certain size installations of engines and drastically alter the industry and air travel.
Quote from irishpilot1990:
The result could be situation with both engines damaged that you have insufficient power and runway disappearing beneath, in general continue unless reasonable happy birds will be avoided!
As you're not pulling your own punches, I'll just say that the above is incoherent, even by the normal standards of these threads. If you want to dish it out, at least try to improve your syntax!
The result could be situation with both engines damaged that you have insufficient power and runway disappearing beneath, in general continue unless reasonable happy birds will be avoided!
As you're not pulling your own punches, I'll just say that the above is incoherent, even by the normal standards of these threads. If you want to dish it out, at least try to improve your syntax!
Avoid imitations
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Unless you have JT8Ds slung on your airplane, then you can plow through anything.
18 November. XV 256 crashed on take off. The aircraft suffered a major bird-strike immediately after take off and crashed into a wooded are to the east of RAF Kinloss air base. Sadly, both pilots were killed but, due to their skill in controlling the crash, the remainder of the crew escaped. Posthumously, Flight Lieutenant Anthony, the flying pilot, was awarded the Air Force Cross and his Co-Pilot, Flying Officer Belcher, the Queen's Commendation for Valuable Service in the Air.
This was a four engined Nimrod, the first one we lost. From my own memory of the accident report, 72 dead gulls were found on the runway.
I picked up a number of Harrier Pilots and flew official photographers at accident sites in RAF Germany in the early 1980s when aircraft were lost due to Pegasus engines being terminally damaged by bird ingestion.
Also, the large flocks of Canada geese living on ponds to the south of Heathrow Airport were/are considered a major flight safety hazard to airliners.
Not convinced that radar works as a bird scarer but forward facing white lights do.
Quote from sevenstrokeroll:
do we think it is safe to say that the high bypass fans /engines are more susceptible by their nature to sucking bigger birds?
More birds, yes; bigger birds, I'm not sure.
Another issue is what happens to the debris of the wretched bird(s) after impact with the fan or spinner. Small birds are unlikely to damage the fan blades themselves, but what you don't want is for debris to enter the core of the engine. Although the JT8D probably picks up fewer birds, the CFM56 (with its much higher bypass ratio) probably ejects a higher proportion of impacting birds (and resulting debris mass) through its C-ducts. Passage through a C-duct, by-passing the core, is unlikely to involve further damage, though it may need to be cleaned.
On a CFM-56 walk-round, finding evidence of blood or very slight damage to the leading edge of a fan blade, it was usually considered OK to dispatch the aircraft provided the point on the blade was well clear of the intake to the core. If there was any doubt, a boroscopic inspection had to be called for. (Personally, in any case, I always had a good look up the back end at the LP turbine.) The great thing about the A320 and B737 is that all of this can be done without the need for a stepladder...
(EDIT) PS, re ShyTorque's post
The Nimrod accident at Kinloss was shocking, not least to other Spey fliers (I was on the BAC1-11 then). The Spey, of course, has an even lower bypass ratio than the JT8D. In view of the enormous number of birds involved, I'm not suggesting the engine type was necessarily a factor. But some thought that the Spey was more vulnerable to bird-strike damage than most.
do we think it is safe to say that the high bypass fans /engines are more susceptible by their nature to sucking bigger birds?
More birds, yes; bigger birds, I'm not sure.
Another issue is what happens to the debris of the wretched bird(s) after impact with the fan or spinner. Small birds are unlikely to damage the fan blades themselves, but what you don't want is for debris to enter the core of the engine. Although the JT8D probably picks up fewer birds, the CFM56 (with its much higher bypass ratio) probably ejects a higher proportion of impacting birds (and resulting debris mass) through its C-ducts. Passage through a C-duct, by-passing the core, is unlikely to involve further damage, though it may need to be cleaned.
On a CFM-56 walk-round, finding evidence of blood or very slight damage to the leading edge of a fan blade, it was usually considered OK to dispatch the aircraft provided the point on the blade was well clear of the intake to the core. If there was any doubt, a boroscopic inspection had to be called for. (Personally, in any case, I always had a good look up the back end at the LP turbine.) The great thing about the A320 and B737 is that all of this can be done without the need for a stepladder...
(EDIT) PS, re ShyTorque's post
The Nimrod accident at Kinloss was shocking, not least to other Spey fliers (I was on the BAC1-11 then). The Spey, of course, has an even lower bypass ratio than the JT8D. In view of the enormous number of birds involved, I'm not suggesting the engine type was necessarily a factor. But some thought that the Spey was more vulnerable to bird-strike damage than most.
Last edited by Chris Scott; 6th Mar 2011 at 12:55. Reason: PS added
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"I offered the bank as an escape maneuver when other options wouldn't work...imagine if that 707 was over your head and you pulled up to avoid the birds...and now you both have TCAS and it issues an escape maneuver."
I'm sorry, but you're writing nonsense. "When other options don't work"??? You must have dual Cray computers, along with internal velocity vector information, horizon display, track while scan capability, along with flight test roll and pitch performance data stored in your brain to be able to see a bird, or birds, compute their exact flight path vs. your flight path, compute closure rate, compute offset space generated by manuevering your aircraft and then HOPE the birds stay on the exact course and altitude.
So you do all of this computing, realize the solution isn't working, and decide - "my moment of fame is upon me! Sixty degrees of bank will save the day!"
Wow.
I'm sorry, but you're writing nonsense. "When other options don't work"??? You must have dual Cray computers, along with internal velocity vector information, horizon display, track while scan capability, along with flight test roll and pitch performance data stored in your brain to be able to see a bird, or birds, compute their exact flight path vs. your flight path, compute closure rate, compute offset space generated by manuevering your aircraft and then HOPE the birds stay on the exact course and altitude.
So you do all of this computing, realize the solution isn't working, and decide - "my moment of fame is upon me! Sixty degrees of bank will save the day!"
Wow.
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I am surprised that so few people can appreciate moving the engines out of the plane of the bird formation.
people have been saying that I must only fly microsoft flight sim...and not real planes. yet I started the thread. and when I did, no one said I was a microsoft sim guy. (by the way, I know how much the microsoft pilots made! wow!).
shytorque...I thought the engines on a nimrod were in the wing and not slung below...and were they JT8D's/??
411a and irishpilot...so , you say the birs are at low level, usually on takeoff , have I said to exceed the max bank for a safe speed? I made a tragic assumption that a pilot would know the various bank angle limits for a speed/confifguration.
irishpilot...leave the thread or the forum when you like. maybe you have never done a 60 degree bank in any plane.
maybe you need a telephone book to see over the anti glare panel.
people have been saying that I must only fly microsoft flight sim...and not real planes. yet I started the thread. and when I did, no one said I was a microsoft sim guy. (by the way, I know how much the microsoft pilots made! wow!).
shytorque...I thought the engines on a nimrod were in the wing and not slung below...and were they JT8D's/??
411a and irishpilot...so , you say the birs are at low level, usually on takeoff , have I said to exceed the max bank for a safe speed? I made a tragic assumption that a pilot would know the various bank angle limits for a speed/confifguration.
irishpilot...leave the thread or the forum when you like. maybe you have never done a 60 degree bank in any plane.
maybe you need a telephone book to see over the anti glare panel.
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sevenstrokeroll:
I made a tragic assumption that a pilot would know the various bank angle limits for a speed/confifguration.
I made a tragic assumption that a pilot would know the various bank angle limits for a speed/confifguration.
Assuming that you are not a pilot I will politely explain in layman's terms:
1) When at the lowest permissibale speed for the current flap setting there is typically 40 degs bank avialable to stickshaker.
2) The actual number of the lowest speed depends on the actual weight of the aircraft
3) It also depends on the altitude, and may be lower at higher altitudes. Boeing does not correct for this and leaves us to guess how much.
4) If you fly faster than the minimum speed you may bank more, but normally we fly pretty close to the minimum speeds, because when the flaps are out we actually want to fly slow.
5) When the flaps are up and we fly faster than the minimum speed for flying without flaps, there is obviously more bank angle available.
All of the above assumes balanced forces (level flight, steady climb or steady descent). If you are willing to compromise your flight path you may bank as much as you like as long as you unload, since an aircraft doesn't stall due to bank angle but due to airflow seperates from the wing. So again, in layman's terms, if you do not pull back on the controls and trade in altitude you can theoretically bank with 90 degs without stalling at any speed (you won't be doing it for long though). Hope this explanation was not too complicated.
Here is what Boeing find sufficient for us to know:
Boeing:
The following tables contain flap maneuver speeds for various flap settings. The flap maneuver speed is the recommended operating speed during takeoff or landing operations. These speeds guarantee full maneuver capability or at least 40° of bank (25° of bank and 15° overshoot) to stick shaker within a few thousand feet of the airport altitude. While the flaps may be extended up to 20,000 feet, less maneuver margin to stick shaker exists for a fixed speed as altitude increases
The following tables contain flap maneuver speeds for various flap settings. The flap maneuver speed is the recommended operating speed during takeoff or landing operations. These speeds guarantee full maneuver capability or at least 40° of bank (25° of bank and 15° overshoot) to stick shaker within a few thousand feet of the airport altitude. While the flaps may be extended up to 20,000 feet, less maneuver margin to stick shaker exists for a fixed speed as altitude increases
sevenstrokeroll: I am surprised that so few people can appreciate moving the engines out of the plane of the bird formation.
Finally, let's see what Boeing writes about steep turns:
Boeing:
Steep Turns
The objective of the steep turn maneuver is to familiarize the pilot with airplane handling characteristics beyond 35° of bank and improve the instrument crosscheck. During training, 45° of bank is used for this maneuver. It is not intended that the pilot should ever be required to bank greater than 25° to 30° in any normal or non-normal condition.
Steep Turns
The objective of the steep turn maneuver is to familiarize the pilot with airplane handling characteristics beyond 35° of bank and improve the instrument crosscheck. During training, 45° of bank is used for this maneuver. It is not intended that the pilot should ever be required to bank greater than 25° to 30° in any normal or non-normal condition.
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Figure out the math on the distance between the engine centerlines -
737 - less than 40'
767 - less than 60'
777 - less than 70'
A 60 degree bank would equate to .9 (90%) of the distance between engines.
So what you're saying is you can estimate, within 30 to 60 feet, exactly where your aircraft and the bird will merge. Based on that you then factor in your roll rate, velocity in feet per second, and then roll at the right time to ensure that one engine goes above the perfect line of birds and another goes through, or below, the flock of birds.
If you can figure it out this well why don't you just pitch up and displace the aircraft 30' with a wings level attitude?
737 - less than 40'
767 - less than 60'
777 - less than 70'
A 60 degree bank would equate to .9 (90%) of the distance between engines.
So what you're saying is you can estimate, within 30 to 60 feet, exactly where your aircraft and the bird will merge. Based on that you then factor in your roll rate, velocity in feet per second, and then roll at the right time to ensure that one engine goes above the perfect line of birds and another goes through, or below, the flock of birds.
If you can figure it out this well why don't you just pitch up and displace the aircraft 30' with a wings level attitude?