Plane Down in Hudson River - NYC
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Like JW, I would prefer the comfort of an APU running. If I had both engines in a sub-idle condition AND height available, I would most certainly consider closing one down and attempting an APU restart.
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I understand your point regarding the term Flame Out. My understanding of this term is its a situation where a Turbine Engine fails to continue operation due to inability to maintain flame propagation through any of a number of extinguishing events. Off the top of my head these would include: Compressor Stalls, Insufficient Airflow, Mass Water Ingestion and or Contaminated Fuel Supply. Basically anything other than a mechanical failure of the Power Plant; which would be classified as an Engine Failure.
Notice I have avoided the use of the term Engine Shutdown which would include Flight Crew operation of normal Fuel Shutoff procedures, Fire T-Handle applications and arguably Running Out of Fuel. I have never stated that the Flight Crew of U.S. Airways Flight 1549 Shutdown the Engines. Once again, my point was simply if the Flight Crew had the APU fully available at the time both engines ceased operations, would that possibly have had an impact on the situation? Specifically, provide instant Pneumatic resources to attempt a restart?
I raise this question because I feel it could have been a factor in this event. Pre-fuel conservation flight ops would not have the APU shutdown before Take off. This current procedure of shutting off the APU after Engine(s) start & restarting upon taxi-in are typical of most Operator's Fuel Saving Programs.
Notice I have avoided the use of the term Engine Shutdown which would include Flight Crew operation of normal Fuel Shutoff procedures, Fire T-Handle applications and arguably Running Out of Fuel. I have never stated that the Flight Crew of U.S. Airways Flight 1549 Shutdown the Engines. Once again, my point was simply if the Flight Crew had the APU fully available at the time both engines ceased operations, would that possibly have had an impact on the situation? Specifically, provide instant Pneumatic resources to attempt a restart?
I raise this question because I feel it could have been a factor in this event. Pre-fuel conservation flight ops would not have the APU shutdown before Take off. This current procedure of shutting off the APU after Engine(s) start & restarting upon taxi-in are typical of most Operator's Fuel Saving Programs.
Cosmo
This is a time dependent judgement. If the engines have gone sub-idle and then the action might have been to turn off the fuel (crew shutdown) and start the restart procedure immediately following the ingestion. Whether you need an APU is subjective to how much altitude and airspeed can you maintain before you hit the ground.
However if the engines are still at or above idle it's a judgement call whether you try and work with a running engine or shut it down and start all over. With lots of altitude you can try several things out. At low altitude you quickly pick whatever is in your experience bank.
Maybe somebody at the NTSB hearing will ask Sully if he had an APU running or not would he have acted differently at the time (hindsight not allowed)
.. (if) APU fully available at the time both engines ceased operations, would that possibly have had an impact on the situation? Specifically, provide instant Pneumatic resources to attempt a restart?
However if the engines are still at or above idle it's a judgement call whether you try and work with a running engine or shut it down and start all over. With lots of altitude you can try several things out. At low altitude you quickly pick whatever is in your experience bank.
Maybe somebody at the NTSB hearing will ask Sully if he had an APU running or not would he have acted differently at the time (hindsight not allowed)
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2 engine a/c, below 10,000 feet, he had the APU running...Unless Airbus deathcruisers are different from Boeings in this respect...
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I can't take it anymore! You're killing me here ....
Sub idle?, with the Power Levers near T/O Power Settings?..Problem??. ARRGHH!!! Take Airspeed and therfore Altitude out of the equation by utilizing APU supplied pneumatics while it's still spooling down.... (My only point thus far.....)
Ignition A&B.... On
Start Intiated...... Boom, (don't even look at the temps, who cares?)
Hang on......
I can only hope some in here are Twin Otter Pilots given the amount of time it takes them in Grasping (or in this case not grasping) a concept.
Adiós All!
Cosmo the Weary-Headed
Ignition A&B.... On
Start Intiated...... Boom, (don't even look at the temps, who cares?)
Hang on......
I can only hope some in here are Twin Otter Pilots given the amount of time it takes them in Grasping (or in this case not grasping) a concept.
Adiós All!
Cosmo the Weary-Headed
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Originally Posted by Downin3
2 engine a/c, below 10,000 feet, he had the APU running...Unless Airbus deathcruisers are different from Boeings in this respect...
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per Cosmo B.
I once worked a pilot writeup of "Flameout with increasing EGT..." which of course is an oxymoron. It was a compressor stall, period (caused by sand/dust erosion) with NO flameout, but RPM rollback.
The term "flameout" is, I'm afraid, still misused by some of the aviation community, and actual flameout (oxidation ceases in the burner) is quite rare, save for fuel starvation.
Correct me if I'm wrong, but I don't believe Sully's CFM56's ever flamed out.
I understand your point regarding the term Flame Out. My understanding of this term is its a situation where a Turbine Engine fails to continue operation due to inability to maintain flame propagation through any of a number of extinguishing events. Off the top of my head these would include: Compressor Stalls, ...
The term "flameout" is, I'm afraid, still misused by some of the aviation community, and actual flameout (oxidation ceases in the burner) is quite rare, save for fuel starvation.
Correct me if I'm wrong, but I don't believe Sully's CFM56's ever flamed out.
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2 engine a/c, below 10,000 feet, he had the APU running...Unless Airbus deathcruisers are different from Boeings in this respect...
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There is no Boeing procedure (737) I know of to regularly leave the APU running for take-off whereas I understand the 320 normally USES the APU for bleeds. Can a 320 driver tell me at what height it is normally shut down?
I can't understand DownIn3green's point.
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Few moments ago saw an interview with a passenger who was sitting in an exit row (so he claimed). When he realised they were headed down said he scrambled to find the briefing card on how to open the exit as he had not a clue. So much for listening to the brief and understanding your responsibilities sitting in that particular window seat. Different circumstances (smoke filled cabin on the runway) may have seen far different result if relying on this individual. Interviewer never picked up on the point.
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Cosmo is obviously a 'wannabe pilot'...
but he's an engineer with some good knowledge!...
but he's not a pilot!...
big difference there, which he doesn't quite get!!
but he's an engineer with some good knowledge!...
but he's not a pilot!...
big difference there, which he doesn't quite get!!
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...and the reason he doesn't get it is because he has no concept of 'real time' !
When a pilot writes up a defect in the part 2, that should take 1/2 an hour to fix, the engineers take the a/c off line for a couple of hours!!!
Sully and co had about 180 seconds to solve a major problem and they did that in exemplary fashion!
Poor old Cosmo would have crashed and burnt in that time and killed himself and a couple of hundred pax!
Better stick with engineering Cosmo, and leave the flying up to the Pros!!
When a pilot writes up a defect in the part 2, that should take 1/2 an hour to fix, the engineers take the a/c off line for a couple of hours!!!
Sully and co had about 180 seconds to solve a major problem and they did that in exemplary fashion!
Poor old Cosmo would have crashed and burnt in that time and killed himself and a couple of hundred pax!
Better stick with engineering Cosmo, and leave the flying up to the Pros!!
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Obie,
I hereby equivically state: I am not a pilot! Also, I am not, have not or will not, fault this flight crew whatsoever! From my very first posts I have praised the flight crew for their performance in this situation. Bravo! great job!
All I was trying to point out was concerning how relatively recent fuel saving procedures may have played a factor in this incident. The operator (company; in this case US Airways) decides at what point in the checklist the APU gets shutdown. Most, until recent fuel price hikes, left the APU until generally second segment climb, or initial cruise settings for two reasons:
1) incase of failures where additional electrical and or pneumatics would be an advantgeous resource for flight crews.
2) to reduce flight crew workload during critical phases of flight or flight transition.
If you feel your checklist procedure is the only way your aircraft can be operated; I suggest you leaf through your MEL under sections 21 & 36 to observe situations where the APU is left running the entire flight. If you are to Pilot a flight on an aircraft with a history of Engine Compressor Stalls, Pressurization events, or any of a number of things where additional electrical or pneumatic sources would be to your advantage; please request some additional fuel to cover the minimal APU burn through to cruise flight just to CYA. I was only trying to offer an additional resource for you to draw from while you guys do that Pilot thing.
As far as your comment about taking too long to change a part... We do whatever we can to prevent similar incidents from occuring. ***My Opinion Only***I feel they blew it in this case and didn't consider everything that could possibly go wrong with a Compressor Stalling Engine. I'm sure the mechanic was only willing to let it go to a major maintenance base where this engine was to be changed (it was headed to a major maintenance hub on this flight). We can't predict everything possible in flight, but we can try to offer you to fly with the most resources available for possible instant fault resolution.
I didn't mean to step on anyone's toes. and Obie if you wish to ignore my advice, go right ahead. It wasn't made with you in mind. Only those willing to listen. Truth is Truth regardless of how insignificant you consider engineers to be, my friend. You are responsible for safe passage of your passengers from chock out until chocks in. I an responsible for every soul who flys in this aircraft from time of repair until it becomes recycled into a beer can. Thank your engineers for taking so long trying to decifer the illogical over simplified squiggles some pilot call write ups; and considering the ramifications of this write up in all phases of flight with regard to safety, chain linked operations and yes, your workload in critical flight phases. Just because a system can be MEL'd doesn't automatically mean it gets MEL'd.
I hereby equivically state: I am not a pilot! Also, I am not, have not or will not, fault this flight crew whatsoever! From my very first posts I have praised the flight crew for their performance in this situation. Bravo! great job!
All I was trying to point out was concerning how relatively recent fuel saving procedures may have played a factor in this incident. The operator (company; in this case US Airways) decides at what point in the checklist the APU gets shutdown. Most, until recent fuel price hikes, left the APU until generally second segment climb, or initial cruise settings for two reasons:
1) incase of failures where additional electrical and or pneumatics would be an advantgeous resource for flight crews.
2) to reduce flight crew workload during critical phases of flight or flight transition.
If you feel your checklist procedure is the only way your aircraft can be operated; I suggest you leaf through your MEL under sections 21 & 36 to observe situations where the APU is left running the entire flight. If you are to Pilot a flight on an aircraft with a history of Engine Compressor Stalls, Pressurization events, or any of a number of things where additional electrical or pneumatic sources would be to your advantage; please request some additional fuel to cover the minimal APU burn through to cruise flight just to CYA. I was only trying to offer an additional resource for you to draw from while you guys do that Pilot thing.
As far as your comment about taking too long to change a part... We do whatever we can to prevent similar incidents from occuring. ***My Opinion Only***I feel they blew it in this case and didn't consider everything that could possibly go wrong with a Compressor Stalling Engine. I'm sure the mechanic was only willing to let it go to a major maintenance base where this engine was to be changed (it was headed to a major maintenance hub on this flight). We can't predict everything possible in flight, but we can try to offer you to fly with the most resources available for possible instant fault resolution.
I didn't mean to step on anyone's toes. and Obie if you wish to ignore my advice, go right ahead. It wasn't made with you in mind. Only those willing to listen. Truth is Truth regardless of how insignificant you consider engineers to be, my friend. You are responsible for safe passage of your passengers from chock out until chocks in. I an responsible for every soul who flys in this aircraft from time of repair until it becomes recycled into a beer can. Thank your engineers for taking so long trying to decifer the illogical over simplified squiggles some pilot call write ups; and considering the ramifications of this write up in all phases of flight with regard to safety, chain linked operations and yes, your workload in critical flight phases. Just because a system can be MEL'd doesn't automatically mean it gets MEL'd.
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ditching switch
While not wanting to fault Capt Sully and F/O or detracting from the praise heaped unto them for the heroics, don't A320/330/340 drivers have a rule of thumb thingy that if one need to ditch ASAP, hit the ditching switch? Well in some LCCs, we do have such " memory " or " recall " action just like if a thrust reverser is inadvertantly deployed after V1 or in takeoff climb ( the manufacturers will swear IT WILL NEVER HAPPEN ), 
he checklist but shutdown the offending engine pronto!!
he checklist but shutdown the offending engine pronto!!
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It's also an option, not all Airlines opted for it, and I think not many more will after this event!
Once again,
To: Captain Sullenberger & his Crew, While I realize you feel as if you were just doing your job, I don't think the same outcome would have happened with many other Crews out there! Great Job Sir!
To: The normally indifferent NYC Ferry-Boat Crews, Thanks for helping out.
(A couple of more minutes though, I'm sure Sullenberger & Crew would have figured out a way to drop his Nose Gear and then he would have taxied it up to the Boat Ramp just so his passengers would have received their Frequent Flyer Miles. The man is amazing!)
Once again,
To: Captain Sullenberger & his Crew, While I realize you feel as if you were just doing your job, I don't think the same outcome would have happened with many other Crews out there! Great Job Sir!
To: The normally indifferent NYC Ferry-Boat Crews, Thanks for helping out.
(A couple of more minutes though, I'm sure Sullenberger & Crew would have figured out a way to drop his Nose Gear and then he would have taxied it up to the Boat Ramp just so his passengers would have received their Frequent Flyer Miles. The man is amazing!)
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APU use regarding performance
The main reason to use an APU for take off is to improve take off performance. APU Bleed can be selected on during the line up leaving more bleed air for the engines. You would only tend to do this when the perfromance was critical.
(The other option is the checklist is to go Packs off on line upwhich achieves the same performance improvement.)
Most operators have APU Off for take off.
(The other option is the checklist is to go Packs off on line upwhich achieves the same performance improvement.)
Most operators have APU Off for take off.