|
ArcMage posted:An overweight landing can gently caress up both your airframe and their runway, and is strongly disfavored, but you do what appears necessary in an emergency and then argue about it on the ground. I feel like the pilots did exactly the right thing but will get chewed out about it.
|
#
?
Jan 16, 2020 14:14
|
|
|
|
| # ? Apr 16, 2024 17:20 |
|
|
I think the pilots didn’t do things quite right, but they didn’t do anything wrong enough that they should be punished.
|
|
#
?
Jan 16, 2020 14:15
|
|
|
Somewhere in the chain a sub-optimal choice was made about fuel dumping, which should be noted for future reference, but I doubt anyone will be getting anything more than a stern talking-to. It likely won't be the pilots themselves on notice for showering an elementary school. E: Like I said, everyone is on the ground now and can shout about it at leisure.
|
|
#
?
Jan 16, 2020 15:11
|
|
|
What would the optimal scenario have been? I assume dumping over the ocean? It's obviously horrible for the environment and clearly something reserved for emergencies anyway, but even when it does happen it just evaporates before it hits the ground doesn't it? lilbeefer fucked around with this message at 15:38 on Jan 16, 2020 |
|
#
?
Jan 16, 2020 15:35
|
|
|
If all that happened is that combustion in one engine went unstable but fixed itself, and there was never anything else wrong, dump fuel over the ocean. If the problem is more serious than that, like a whiff of anything unusual from the good engine, turn around and land overweight immediately. Rule‐of‐thumb for fuel evaporation is that it takes four thousand feet in summer weather and seven thousand in the winter. Burning the fuel by circling for hours would technically be less lovely for the environment than dumping unburnt fuel—combustion products are less noxious than VOCs—but no one is going to do that in a plane that features dump valves.
|
|
#
?
Jan 16, 2020 16:13
|
|
|
Wow thanks that learned me good
|
|
#
?
Jan 16, 2020 16:29
|
|
|
lilbeefer posted:What would the optimal scenario have been? I assume dumping over the ocean? It's kerosene
|
|
#
?
Jan 16, 2020 16:54
|
|
|
ArcMage posted:An overweight landing can gently caress up both your airframe and their runway, and is strongly disfavored, but you do what appears necessary in an emergency and then argue about it on the ground. Platystemon posted:I think the pilots didn’t do things quite right, but they didn’t do anything wrong enough that they should be punished. 
e.pilot fucked around with this message at 17:04 on Jan 16, 2020 |
|
#
?
Jan 16, 2020 17:01
|
|
|
I hate the jet fuel mythos, had people ask all the time during airshows if I would put jet fuel in their truck for them so they could get some 'real performance' out of it. 'Is your truck a diesel?' 'No' 'I'm not going to be a party to you destroying your engine' Alternatively 'Yeah it's a diesel' 'Then put some road diesel in it' Yeesh, it's not some magical super fuel, it just burns differently EvenWorseOpinions fucked around with this message at 17:23 on Jan 16, 2020 |
|
#
?
Jan 16, 2020 17:21
|
|
|
e.pilot posted:Not as disfavored as dumping fuel and wasting time dumping fuel. I mean, yes, if your emergency calls for immediate return to airfield?
|
|
#
?
Jan 16, 2020 17:37
|
|
|
ArcMage posted:I mean, yes, if your emergency calls for immediate return to airfield? There’s no reason to dump fuel, the planes can be safely landed overweight, they’re designed to be, they just couldn’t handle the extra wear and stress of multiple daily landings at those weights. It’s actively discouraged in training and checklists will state it is optional.
|
|
#
?
Jan 16, 2020 17:41
|
|
|
EvenWorseOpinions posted:I hate the jet fuel mythos, had people ask all the time during airshows if I would put jet fuel in their truck for them so they could get some 'real performance' out of it. Anecdotally, but the two diesel fuel trucks I used to work with both needed significant engine work done to them after running on Jet A for a couple years.
|
|
#
?
Jan 16, 2020 19:22
|
|
|
EvenWorseOpinions posted:I hate the jet fuel mythos, had people ask all the time during airshows if I would put jet fuel in their truck for them so they could get some 'real performance' out of it. Probably morons who heard about some racecars running on 100LL and assumed jets bettar go fastar
|
|
#
?
Jan 16, 2020 19:49
|
|
|
Arson Daily posted:Anecdotally, but the two diesel fuel trucks I used to work with both needed significant engine work done to them after running on Jet A for a couple years. If they were the Ford 6.0 severe problems are a foregone conclusion.
|
|
#
?
Jan 16, 2020 20:08
|
|
|
lilbeefer posted:What would the optimal scenario have been? I assume dumping over the ocean? It's not really that horrible for the environment. Kerosene ultimately comes from the ground after all 
|
|
#
?
Jan 16, 2020 20:30
|
|
|
Arson Daily posted:Anecdotally, but the two diesel fuel trucks I used to work with both needed significant engine work done to them after running on Jet A for a couple years. I've heard that jet fuel has less lubricity than diesel and ends up hurting fuel pumps and stuff. At the place I used to work we collected any jet fuel we couldn't put back into aircraft for our diesel tractor and would dump in some 5606 for lubricity and I was skeptical, but it worked fine as far as I could tell. tactlessbastard posted:Probably morons who heard about some racecars running on 100LL and assumed jets bettar go fastar We had an insufferable bro dude in AP school who was insufferable for so many reasons, including talking about how he ran 100ll in his truck because *vomit* He never took his catalytic converter out so lol if he actually ran 100ll in it, but he was constantly full of poo poo so who knows
|
|
#
?
Jan 16, 2020 21:07
|
|
|
EvenWorseOpinions posted:I've heard that jet fuel has less lubricity than diesel and ends up hurting fuel pumps and stuff. Anything that runs on diesel will run on Jet-A for at least a little while. The combustion characteristics are close enough as to not matter. Lubricity is an issue with fuel pumps and such over long term use. (Or in short term use, in the case of common rail direct fuel injection pumps.) Similar to how a jet engine will run fine on AVGAS, but long term use will ruin the hot section.
|
|
#
?
Jan 16, 2020 21:30
|
|
|
EvenWorseOpinions posted:I've heard that jet fuel has less lubricity than diesel and ends up hurting fuel pumps and stuff. At the place I used to work we collected any jet fuel we couldn't put back into aircraft for our diesel tractor and would dump in some 5606 for lubricity and I was skeptical, but it worked fine as far as I could tell. I’ve heard that same thing! These were 98 or 99 MY ford 7.3 motors, before all the new diesel shenanigans took effect.
|
|
#
?
Jan 16, 2020 22:45
|
|
|
KYOON GRIFFEY JR posted:you kinda answered your own question in there - passengers on a long haul to Shanghai are not going to be comfortable with the aircraft Didn't notice THAT was the destination. Yeah, ok.
|
|
#
?
Jan 17, 2020 03:08
|
|
|
e.pilot posted:There’s no reason to dump fuel, the planes can be safely landed overweight, they’re designed to be, they just couldn’t handle the extra wear and stress of multiple daily landings at those weights. It’s actively discouraged in training and checklists will state it is optional. I mean doesn’t a compressor stall indicate something ain’t right with that engine? What if it poo poo the bed on short final or the stall caused damage? Not trying to poke at you, I’m really wondering. I feel like they were just making a prudent decision by dumping gas. Just go higher altitude next time.
|
|
#
?
Jan 17, 2020 04:13
|
|
|
A compressor stall just means that something screwed up the airflow through the engine. It could be something mechanically wrong, sure, or it could be a bird getting sucked in and disintegrated, or it ingested a bunch of water or ice or hail, or the plane was flown in a weird maneuver, or whatever. I understand that before FADEC compressor stalls were quite common just from improper procedures, like advancing the throttle too quickly. A single brief compressor stall followed by a return to normal operation is not necessarily an emergency. I can't find any general FAA rule on the subject but I bet the official line is "if the airplane's operational manual says that you can keep flying after a compressor stall, then you can do so; if not, then you can't."
|
|
#
?
Jan 17, 2020 04:23
|
|
|
The main difference between jet fuel and diesel is how much water you can have in either by standard. The tolerance for jet fuel is much, much lower. Jet fuel is harder to ignite too, IIRC.
|
|
#
?
Jan 17, 2020 04:41
|
|
|
Sagebrush posted:A compressor stall just means that something screwed up the airflow through the engine. It could be something mechanically wrong, sure, or it could be a bird getting sucked in and disintegrated, or it ingested a bunch of water or ice or hail, or the plane was flown in a weird maneuver, or whatever. I understand that before FADEC compressor stalls were quite common just from improper procedures, like advancing the throttle too quickly. But like, you don’t know if it was a mechanical thing or a bird or a chunk of ice, right? And if it’s super uncommon with fadecs, why would you keep flying any longer than you had to after this rare thing happened? I maintain it’s prudent. We’d be calling them fools if they pancaked that plane or limped it across the ocean single engine because of damage a stall did earlier.
|
|
#
?
Jan 17, 2020 05:21
|
|
|
I would 100% declare an emergency and return to land for a compressor stall. Post landing I'd have CFR inspect the engine to make sure we're not leaking fluids or dragging parts on the ground before we taxi back to the gate. I get paid the same if the flight continues, returns, or never even leaves the gate. I do not get paid to be a hero.
|
|
#
?
Jan 17, 2020 05:32
|
|
|
Back in September of 1993, on a TWA flight from FCO to JFK on a 747-200, my family was coming home from my father's command tour and as the engines spooled up on takeoff, the pilot rejected the takeoff, sided off into the taxiway, made a vague PA about 'checking the engines,' spooled the engines up a few times to see if it was repeatable, then we took off as if nothing happened. The flight was otherwise uneventful. Everyone's assholes were puckered a little tighter that flight, though, even the flight attendant's, and that was with *four* engines and a flight engineer to babysit the gauges the whole flight. Still, I can't help but think that wasn't the right course of action. BIG HEADLINE fucked around with this message at 06:11 on Jan 17, 2020 |
|
#
?
Jan 17, 2020 05:43
|
|
|
Sagebrush posted:A compressor stall just means that something screwed up the airflow through the engine. It could be something mechanically wrong, sure, or it could be a bird getting sucked in and disintegrated, or it ingested a bunch of water or ice or hail, or the plane was flown in a weird maneuver, or whatever. I understand that before FADEC compressor stalls were quite common just from improper procedures, like advancing the throttle too quickly. I would assume any applicable rule would be an ETOPS one. If engines turn or passengers swim them a questionable engine is probably not acceptable.
|
|
#
?
Jan 17, 2020 06:08
|
|
|
Bob A Feet posted:I mean doesn’t a compressor stall indicate something ain’t right with that engine? What if it poo poo the bed on short final or the stall caused damage? Not trying to poke at you, I’m really wondering. I feel like they were just making a prudent decision by dumping gas. Just go higher altitude next time. It does but dumping fuel still does nothing for you except waste time and fuel that you might need if something goes more wrong. Landing over weight for an emergency situation does not matter, full stop. For starters single engine go around performance is predicated on max takeoff weight, so that's moot. Let's say something catastrophic happened with that engine, not a fire but some real good structural damage, like that Southwest flight a couple years ago. There's no way to know how much damage there might be out there, why linger in the air dumping fuel when you can just get on the ground before something potentially gets worse. Or let's say your landing weight is very close to your reserve fuel weight or min go around fuel, you start dumping fuel to make your max landing weight and have to go around for some reason, or you have to divert to another airport because the engine you just fragged on takeoff left FOD all over the runway. Now you've just reduced your options. But what if there's a post crash fire! 100k lbs of fuel will burn basically indistinguishably from 50k lbs. Dumping fuel to get under max landing weight is an outdated idea and there is no reason to do it, period. KodiakRS posted:I would 100% declare an emergency and return to land for a compressor stall. Post landing I'd have CFR inspect the engine to make sure we're not leaking fluids or dragging parts on the ground before we taxi back to the gate. There's not really a way to know if that's what it is 100% either, could have been a bird strike or FOD ingestion as well causing the flameout/surge. e.pilot fucked around with this message at 06:26 on Jan 17, 2020 |
|
#
?
Jan 17, 2020 06:24
|
|
|
If you've just taken off for a flight across the Pacific and one of the engines on a twin-engine jet is already acting funny, the answer is turn around and land.
|
|
#
?
Jan 17, 2020 06:24
|
|
|
Diesel fuel has molecules skewed toward longer carbon chains and higher boiling points than kerosene (and consequently jet A). They overlap plenty, but kerosene lacks the oilier molecules that diesel has and diesel is deficient in the aromatic end. The difference is greater with jet B, used in very cold climates, or JP‐4, the old DoD standby. That stuff is basically equal parts kerosene and gasoline. JP‐5 is the opposite. It’s kerosene with the aromatics boiled off so it’s less likely to turn your aircraft carrier into a bomb.  This illustration understates the overlap, but it conveys the idea.
|
|
#
?
Jan 17, 2020 06:26
|
|
|
Platystemon posted:Diesel fuel has molecules skewed toward longer carbon chains and higher boiling points than kerosene (and consequently jet A). They overlap plenty, but kerosene lacks the oilier molecules that diesel has and diesel is deficient in the aromatic end. Cool, I was kind of curious how heating oil compared. The smell is kind of like an airport. Also fuel dumping still happens often enough, guess they didn't get the memo?
|
|
#
?
Jan 17, 2020 06:36
|
|
|
№ 2 fuel oil is basically the same stuff as diesel. Industry uses heavier fuel oils in things like oil‐fired electrical plants and large ships. Heavy fuel oil won’t flow at room temperature and has to be preheated to move through the pipes. It’s common to start on a lighter fuel, then switch to the heavy stuff.
|
|
#
?
Jan 17, 2020 06:52
|
|
|
I'm sure there are some pencil-pushers at every airline figuring out exactly how the cost of the wasted fuel (and the potential costs of the safety concerns outlined by e.pilot) compares to the cost of the inspection and maintenance required by landing overweight, and coaching the pilots to dump the fuel whenever the numbers work out in their favor. On a semi-related note: I went to a safety seminar at my flight school and there was a guy there from SFO talking about TCAS RA alerts caused by light aircraft (read: you stupid student pilots) flying real close to the SFO approach corridor. He said that it costs an airline $20,000 to abort their landing and go around because of a collision alert. Does that number sound right to the airline pilots in here?
|
|
#
?
Jan 17, 2020 06:54
|
|
|
Depends on the plane but fuel alone for a go around can get pretty bananas, a lap around the pattern in the 767 would be around 5-10k lbs of fuel depending how far you get vectored out (750-1,500gal) add in overall maintenance, possible missed connections, it adds up pretty quickly.
|
|
#
?
Jan 17, 2020 07:18
|
|
|
Isn't e.pilot an actual commercial pilot? I don't think he wants to be all "look at m'dick I'm a pilot" but I think he's pretty much the technical authority on this.
|
|
#
?
Jan 17, 2020 07:26
|
|
|
Charles posted:Cool, I was kind of curious how heating oil compared. The smell is kind of like an airport. If you forget to order heating oil for your furnace (like my scatterbrained coworker) and it magically becomes winter and you can't heat the house, you can run your furnace on a jerrican of diesel from the local petrol station until you can convince the truck to come around
|
|
#
?
Jan 17, 2020 07:31
|
|
|
Elviscat posted:Isn't e.pilot an actual commercial pilot? I don't think he wants to be all "look at m'dick I'm a pilot" but I think he's pretty much the technical authority on this. I wouldn’t say I’m the technical authority, I’m not nearly as experienced and knowledgeable as I wish I were, but I do fly large airplanes for a living yes. e: Oh I did neglect one reason where you would have to dump fuel, if for some reason the landing distance needed you to be below a certain weight, but that’s not really a concern at any large US airports, but runway available is definitely factored in to such decisions. e.pilot fucked around with this message at 08:19 on Jan 17, 2020 |
|
#
?
Jan 17, 2020 08:12
|
|
|
Here's the video of that Air China flight from IAD to PEK that suffered a compressor stall post-rotation: https://www.youtube.com/watch?v=GMwq_NDNa48 There's a VASAviation ATC log as well on Youtube.
|
|
#
?
Jan 17, 2020 08:45
|
|
|
Here's a video of a pilot https://www.youtube.com/watch?v=1BzU1sYPjzo
|
|
#
?
Jan 17, 2020 12:33
|
|
|
Anyone ever slept in the crew rest compartment on an airliner? They look a bit claustrophobic.
|
|
#
?
Jan 17, 2020 14:04
|
|
|
|
| # ? Apr 16, 2024 17:20 |
|
|
I would blow Dane Cook posted:Anyone ever slept in the crew rest compartment on an airliner? I stayed in a tube hotel for fun in Sydney once. I get some fun PTSD, sleep paralysis and night terrors on occasions. That time it was not fun.
|
|
#
?
Jan 17, 2020 14:45
|
|
