Here's a little sumpthin' from the NTSB boys on the unscheduled water landing on the Hudson by a fellow alumnus...
- I seem to remember Bill O'Reilly starting to go into high dudgeon about the engines, i.e., he was going to get to the bottom of this vis-a-vis these (potentially) GE pieces of crap if that's what caused the jet to turn into an expensive French glider. I paraphrase of course, but that was my impression from catching snippets of his show shortly after the incident.
From reading the third and fourth paragraphs, this does not seem to be the case. First, the 13 January surge well before the day of the accident caused by a sensor failure is not a terribly unusual event...sensors fail and engines sometimes get goofy as a result; they won't explode and the worst case is usually an uncommanded shutdown.
This sounds scary but it's nowhere near the crisis of a complete thrust loss due to bird ingestion. In fact, I'm MUCH more afraid of the latter than I am of the former (and I do this for a living).
Second, the boroscope inspection is quite thorough...one blade at a time with a powerful light and something that resembles what they use on you in a colonoscopy. Third, US Air had complied with a directive for inspecting the engines...if the NTSB says so, I believe 'em, 'cause their investigations are fully open to the public and the press and their teams are shadowed by both reporters and lawyers. They would NOT cover this up (despite what Kos or Rosie O'Donnell might think) because of the way their process is designed.
- Taking off out of La Guardia SUCKS. Not only is the traffic congestion monumental and the radios jammed with Ground, Tower, Departure, et al., sitting in the departure position waiting for clearance to roll is an exercise in Hope and Change, as in
Many a pilot has hit birds and none of us like it, but there are birds and there are birds. Canadian geese are the avian equivalent of cannon balls...big, heavy and dense. Perfect engine trashers. NOTE: testing has shown that chickens and sparrows are mere trifles to most of the larger jet engines...pigeons, on the other hand are like little cannon balls--small, heavy and dense...and hell on engines.
So, Sully hit what is probably the biggest threat in the New York bird migration pantheon. He went through so many so suddenly that NO motor would have come out of this unscathed and frankly I'm surprised there wasn't a bigger "bang" after impact from internal damage, i.e., a fire or fires from broken fuel lines, ruptured flight control lines, etc. In fact, thank God none of them hit the windscreen dead on. Guys have died from getting turkey buzzards in the face (literally) so the fact that the cockpit was complete;y missed was a very good thing. At departure speeds, I doubt even a Canadian goose would have penetrated the flight deck but at least he didn't have the distraction of a major splatter on the window.
-Finally, NTSB reports take forever, thanks to the "openness" framework. Openness is great if you want to assign blame, which is what the NTSB does, basically, after reconstructing the chain of events after the accident based on evidence available. That's why there's about 100 lawyers in the back of the room when the Board briefs...and a massive use of cell phones to law firms after that to lay litigation groundwork. Of course, this does very little to prevent accidents because most surviving crew members won't say squat to anybody without their own legal counsel and union reps present, and then they'll say very little.
The media O'Reillys and the Dewey, Cheatum and Howe legal beagles of the world are looking for scalps. That's one reason I miss the USAF's Mishap Investigation Boards (as opposed to the NTSB-like Accident Board that follows). Nothing said in the former could be used against a witness for punitive purposes. The objective was determining cause and implementing preventive measures in future operations...and why a full report could be generated 30 DAYS after the MIB convened. But I digress...
What Captain Sullenberger did was amazing. CIrcumstances were such that he was able to apply his superior skills and judgement to great effect. This was truly one for the history books and I mean that literally. There was no mystery to why he had to land earlier than he originally planned...he hit a bunch of big-ass birds that trashed his thrusters and left him with zero options. Nothing to suspect here...lots to praise and be grateful for. -Attila
Now, a couple of points:************************************************************
NTSB ADVISORY
************************************************************National Transportation Safety Board Washington, DC 20594February 4, 2009************************************************************
THIRD UPDATE ON INVESTIGATION INTO DITCHING OF US AIRWAYS JETLINER INTO HUDSON RIVER
************************************************************The following is an update on the National Transportation Safety Board's investigation of US Airways flight 1549, which ditched into the Hudson River on January 15, 2009.
The left (#1) engine, which was recovered from the Hudson River on January 23 and subsequently shipped to the manufacturer in Cincinnati where the NTSB is directing a teardown, was found to contain bird remains. The organic material found in the right (#2) engine has also been confirmed to be bird remains. The material from both engines has been sent to the Smithsonian Institution in Washington where the particular bird species will be identified.
As part of its investigation into this accident, the NTSB investigated an engine surge event that occurred in the right (#2) engine during a flight on January 13, two days prior to the accident. The engine recovered from the surge and the remainder of the flight was completed uneventfully. The NTSB determined that the surge was due to a faulty temperature sensor, which was replaced by maintenance personal following approved procedures. After the engine was examined with a boroscope and found to be undamaged and in good working order, the aircraft was returned to service.
On December 31, 2008, the Federal Aviation Administration (FAA) issued an Airworthiness Directive (AD) covering all CFM56-5B series turbofan engines, the same type that was on the accident aircraft. After examining the engine maintenance records and interviewing relevant personnel, the NTSB determined that all of the requirements of the AD were complied with prior to the accident flight.
During the accident flight, the flight data recorder revealed no anomalies or malfunctions in either engine up to the point where the captain reported a bird strike, after which there was an uncommanded loss of thrust in both engines.
Last week the aircraft was moved from the barge where it had been docked in Jersey City, NJ, to a secure salvage yard in Kearny, NJ, where it will remain throughout the NTSB investigation, which is expected to last 12-18 months.
Photo of feather found in the left (#1) engine
NTSB Media Contact: Peter Knudson (202) 314-6100 peter.knudson@ntsb.gov
- I seem to remember Bill O'Reilly starting to go into high dudgeon about the engines, i.e., he was going to get to the bottom of this vis-a-vis these (potentially) GE pieces of crap if that's what caused the jet to turn into an expensive French glider. I paraphrase of course, but that was my impression from catching snippets of his show shortly after the incident.
From reading the third and fourth paragraphs, this does not seem to be the case. First, the 13 January surge well before the day of the accident caused by a sensor failure is not a terribly unusual event...sensors fail and engines sometimes get goofy as a result; they won't explode and the worst case is usually an uncommanded shutdown.
This sounds scary but it's nowhere near the crisis of a complete thrust loss due to bird ingestion. In fact, I'm MUCH more afraid of the latter than I am of the former (and I do this for a living).
Second, the boroscope inspection is quite thorough...one blade at a time with a powerful light and something that resembles what they use on you in a colonoscopy. Third, US Air had complied with a directive for inspecting the engines...if the NTSB says so, I believe 'em, 'cause their investigations are fully open to the public and the press and their teams are shadowed by both reporters and lawyers. They would NOT cover this up (despite what Kos or Rosie O'Donnell might think) because of the way their process is designed.
- Taking off out of La Guardia SUCKS. Not only is the traffic congestion monumental and the radios jammed with Ground, Tower, Departure, et al., sitting in the departure position waiting for clearance to roll is an exercise in Hope and Change, as in
"I HOPE those *&!#&$!! birds I see off the end of the runway CHANGE their *&!#&$!!-ing flight path before I get there."
Many a pilot has hit birds and none of us like it, but there are birds and there are birds. Canadian geese are the avian equivalent of cannon balls...big, heavy and dense. Perfect engine trashers. NOTE: testing has shown that chickens and sparrows are mere trifles to most of the larger jet engines...pigeons, on the other hand are like little cannon balls--small, heavy and dense...and hell on engines.
So, Sully hit what is probably the biggest threat in the New York bird migration pantheon. He went through so many so suddenly that NO motor would have come out of this unscathed and frankly I'm surprised there wasn't a bigger "bang" after impact from internal damage, i.e., a fire or fires from broken fuel lines, ruptured flight control lines, etc. In fact, thank God none of them hit the windscreen dead on. Guys have died from getting turkey buzzards in the face (literally) so the fact that the cockpit was complete;y missed was a very good thing. At departure speeds, I doubt even a Canadian goose would have penetrated the flight deck but at least he didn't have the distraction of a major splatter on the window.
-Finally, NTSB reports take forever, thanks to the "openness" framework. Openness is great if you want to assign blame, which is what the NTSB does, basically, after reconstructing the chain of events after the accident based on evidence available. That's why there's about 100 lawyers in the back of the room when the Board briefs...and a massive use of cell phones to law firms after that to lay litigation groundwork. Of course, this does very little to prevent accidents because most surviving crew members won't say squat to anybody without their own legal counsel and union reps present, and then they'll say very little.
The media O'Reillys and the Dewey, Cheatum and Howe legal beagles of the world are looking for scalps. That's one reason I miss the USAF's Mishap Investigation Boards (as opposed to the NTSB-like Accident Board that follows). Nothing said in the former could be used against a witness for punitive purposes. The objective was determining cause and implementing preventive measures in future operations...and why a full report could be generated 30 DAYS after the MIB convened. But I digress...
What Captain Sullenberger did was amazing. CIrcumstances were such that he was able to apply his superior skills and judgement to great effect. This was truly one for the history books and I mean that literally. There was no mystery to why he had to land earlier than he originally planned...he hit a bunch of big-ass birds that trashed his thrusters and left him with zero options. Nothing to suspect here...lots to praise and be grateful for. -Attila
This does make me wonder, though...could there be some way to fit podded turbofans with some kind of anti-FOD device for takeoffs and landings? I mean the MiG-29 has some kind of variable-geometry intake nacelles that change the airflow pattern for takeoffs on unimproved airstrips to avoid ingestion of crap on the ground, although I don't know if it helps any for avoiding birdstrikes, and the engine layout is very different, as they're buried in those under-fuselage nacelles.
I'm thinking maybe some kind of system with wires set into the outer rim of the intake, with one end of each wire fixed and the other on a little roller, so they make a web pattern when extended and then at a few thousand feet the pilot hits the switch and they retract back into the rim...
Alas, the mass flow requirement for today's commercial engines is too great to allow for "armor" in front of the intakes for takeoff.
Granted, there have been designs like the one you refer to but they were conceived for scenarios commercial jets would never face, like landing on/taking off from unimproved fields. Also, I'm not so sure the MiG or Sukhoi designs were more than a "good idea." If I remember correctly, the main intake opens during takeoff on nose strut extension (I think) and closes on main gear touchdown on landing and dorsal intake opens above the now-closed primary intake while the latter is closed. Even a Russian fighter, with its HUGE brute-force engineered stainless steel engines-from-hell would have major problems with thrust requirements on takeoff with this configuration because those requirements would dwarf anything required when recovering. The departing jet is loaded for combat (fuel, ordnance, etc.) and it is trying to overcome gravity, not using it to return to earth at relatively low power settings.
Finally, the bird strike risk does not overshadow the loss-of-thrust risk imposed by a however-temporary obstruction over the intake. Then there's ice buildup on something like that on a winter day while taxiing to the runway, etc., etc., etc.
In short, it sounds good, but it's way too impractical.
I guess my basic idea I'm trying to describe is not "armor" so much as an attempt to deploy some sort of "screen"-like device over the intake that, at relatively low velocities, where air can be approximated as an extremely low-viscosity fluid (unlike cruising velocities, where air begins to approximate a high-viscosity fluid, AND you get into problems with shockwaves and such), will not significantly hinder airflow, while at the same time (mostly depending on collision speed), either deflecting or "chopping up" any flying animals or other objects that might be in the air (stray parachuters, weather balloons, whatever) before they hit the turbine blades. It's not so much an apparatus to completely shield the intake, as that would be incompatible with achieving takeoff thrust, as it is an attempt to mitigate the damage of a birdstrike or something like that.
All my engineer buddies tell me stuff in front of the intake is basically a Bad Thing, regardless of its relative "density."
As far as shock waves go, not that big a deal on something as slow as a commercial jet. "Slow" is relative, but a 'Bus motors around at something like .78 Mach and very much slower in the departure/arrival pattern (I know...they force me to slow down in the pattern all the time). Ironically, being slow requires MORE power than at cruise so any obstruction to flow, no matter how minor, comes at great cost.
Now, if we're talking Mach 3+, or even transonic/low supersonic, yeah, now you're getting into variable geometry intake ramps (F-15) and/or shock cones (SR-71). Take a close look at the spinners on a commercial jet next time you get a chance...not much "pointyness" there 'cause it isn't necessary, but anything in front of that big hole is looked on with extreme suspicion by engineer and pilot alike.
Plus the thing would be a magnet for ice, so it would have to be heated, and preheating air going into the engine also reduces its performance.
Personally I think the effort would be best invested in small chemical lasers to shoot the bastards down before they can get ingested. They are always flying without transponders and refusing ATC vectors anyway. Somebody ought to pull their ticket.
I'd tell ya that too, but then again, we'll also tell you that engineering is often a tradeoff between one Bad Thing or another.
As far as shock waves go, not that big a deal on something as slow as a commercial jet. [...] Ironically, being slow requires MORE power than at cruise so any obstruction to flow, no matter how minor, comes at great cost.
Yeah in this particular case I guess the shockwaves aren't really the issue so much as the problems with drag and turbulence on the airflow (since you want smooth airflow into the intake), although airspeed is more important here than engine power.
but anything in front of that big hole is looked on with extreme suspicion by engineer and pilot alike
Certainly true, which is why it's vital that any device be designed so that it's only "in front of the hole" on takeoff (and maybe landing), and then gets out of the way.
Hmmm the high-bypass turbofans popular these days certainly DO make it more of a problem. What happened to the good old days with those good old noisy, smoky turbojets?
Plus the thing would be a magnet for ice, so it would have to be heated, and preheating air going into the engine also reduces its performance.
If it were in fact some kind of device utilizing metal cables, maybe you could just run electrical current right through them? That wouldn't affect performance nearly as much as blowing hot bleed air all over them.
Personally I think the effort would be best invested in small chemical lasers to shoot the bastards down before they can get ingested. They are always flying without transponders and refusing ATC vectors anyway. Somebody ought to pull their ticket.
Damn straight! But instead of lasers, why not mount a bunch of tiny little 3 inch long miniature AIM-9s by each engine?
Can something be mounted on an aircraft to get these birds out of the way one way or the other? Is it worth it to do that? If it's really good it can pluck them and serve in flight. :D
Litigation really is the paralysis of our modern society.
Turkey buzzards are the worst. They barf when they think they're being threatened, and remember what they *eat*...
Bill O'Reilly has a problem, he gets an idea in his head and you can't knock it out with a baseball bat. Now, sometimes that's a good thing but not always. O'Reilly has a vendetta againist GE and its chairman Jeffrey Immelt and anything he can pelt them with he will.
As for geese, they're small potatoes. there is a small lake (pond really, but the city owns it so it's a lake) here where geese always stop by and they are sometimes joined by trumpeter swans. I went out and took a picture there last week and I was struck by how much larger the swans were than the geese.
http://www.nevadadailymail.com/story/1497790.html
BTW my dad had a saying about cr*p through a goose and I never understood why their digestive systems would be any speedier than any others but after seeing all those geese I can at least attest to the AMOUNT they produce.
Two words vis-a-vis deer sirens: "Doppler effect."
NDSteve,
My huntin' friends tell me a goose makes a hell of a "thump" when they hit the deck after taking on excessive buckshot. The swans may be bigger, but the geese are WAY big enough to hammer an engine. (US1549=QED).
I was thinking more along the lines of "Redneck Airways..."
Maybe we just need to paint the airplanes to look like birds of prey, like those hawk sillhouettes you're supposed to put on picture windows to keep the birds from smacking into them...
The screens were primarily intended to prevent FOAD from Russian runways and probably not sized to counter geese. The FOAD would have been thrown up by the nosewheel, and thus the screens closed the inlet when the wheel was on the ground. Apparently the transition from ducts closed to ducts open had little effect on the takeoff as sensed by the pilot. From the exterior observer, the operation was very quick.
No, the screen would not stop a goose.
Cheers