Boeing 777 Disappears Near Vietnam

[On Guard for Thee]

No, that does not answer my question.

Is there evidence to distinguish how the engines were shut down, yes or no!?

WWWTT

The only way you'd be able to know that would be if you were in the cockpit.

[Michael Hardner]

No evidence the plane crashed so it must of landed somewhere. Wait a minute, there is no evidence of that either.

That's what I was thinking.

[WWWTT]

The only way you'd be able to know that would be if you were in the cockpit.

So in other words there is no evidence that the engines were or were not manually shut down as opposed to being starved of fuel or any other means of shutting down.

WWWTT

[On Guard for Thee]

So in other words there is no evidence that the engines were or were not manually shut down as opposed to being starved of fuel or any other means of shutting down.

WWWTT

As far as I know there is no evidence of how the engines were shut down. What would be a good clue would be whether the engines were shut down at the same, or near to the same time. That would indicate manual shut down. Unlikely that fuel starvation would happen for both engines at exactly the same time. But it could.

[Wilber]

Most unlikely, especially if the pilots hadn't been balancing fuel during the flight. That brings up another question, what would have happened with one engine shut down if no one was flying the aircraft.

[bush_cheney2004]

There are several forums with B777 pilot explanations of what turns out to be a complex series of flight events upon loss of engine(s) power. Here is one scenario as seen in the simulator:

When the first engine failed TAC (Thrust asymmetry compensation) automatically applied rudder. The speed reduced from 320 knots indicated to 245 knots indicated. It was able to maintain 245 knots and FL250. When the second engine failed the rudder trim applied by TAC was taken out and the trim went to zero. The autopilot dropped out and the flight controls reverted to direct mode. The speed initially came back to 230 knots but then the nose started to lower. The nose continued to lower and the rate of descent increased to 4,000 feet per minute, the nose kept lowering and the descent rate increased to 7,500 feet per minute with a bank angle that increased to 25 degrees. The speed at this point had increased to 340 knots indicated, above VMO but there was no horn as it was on limited electrics. About this point the RAT (Ram air turbine) chipped in and the CDUs and copilot's PFD (Primary flight display) came alive. The flight controls stayed in direct mode.The eicas screen was full of messages like pitot heat, flight controls, APU fault (The APU had tried to autostart due double engine failure but failed due no fuel to start it) low fuel pressure etc.

http://www.pprune.org/tech-log/537103-fuel-starvation-autopilot.html#post8412514

[On Guard for Thee]

Most unlikely, especially if the pilots hadn't been balancing fuel during the flight. That brings up another question, what would have happened with one engine shut down if no one was flying the aircraft.

My guess would be a yaw exceeding the authority of the AP and a roll toward the dead engine and then some kinda crazy spin into the chuck.

[Wilber]

My guess would be a yaw exceeding the authority of the AP and a roll toward the dead engine and then some kinda crazy spin into the chuck.

Depend on what kind of authority the AP has, altitude etc. The aircraft would be pretty light by then and it might be able to handle it with a whole whack of aileron. Some of these aircraft can but the amount of uncorrected yaw sure tends to mess with their ability to mantain a course. So where would it have headed then and for how long?

[On Guard for Thee]

Depend on what kind of authority the AP has, altitude etc. The aircraft would be pretty light by then and it might be able to handle it with a whole whack of aileron. Some of these aircraft can but the amount of uncorrected yaw sure tends to mess with their ability to mantain a course. So where would it have headed then and for how long?

I was looking around on the net and I can't seem to find anything, especially from Inmarsat, that shows the length of time of dyssimatery of thrust. But I wonder after 7 hours or so of nobbody minding the store, how unbalanced might the fuel become.

[jbg]

One way or the other they quit. Why would you shut them down over the ocean?

Maybe the pilot was in the mood for a swim.

[On Guard for Thee]

Maybe the pilot was in the mood for a swim.

That's possible. I just wish he'd get to shore and do some 'splainin.

[Wilber]

I was looking around on the net and I can't seem to find anything, especially from Inmarsat, that shows the length of time of dyssimatery of thrust. But I wonder after 7 hours or so of nobbody minding the store, how unbalanced might the fuel become.

Apparently this aircraft had Rollers with which I am not familiar. I do know that Boeing's FADEC system will keep fan speed on GE's synchronized to with a tenth of a percent N1. Any difference in fuel consumption is due to engine condition.

[On Guard for Thee]

Apparently this aircraft had Rollers with which I am not familiar. I do know that Boeing's FADEC system will keep fan speed on GE's synchronized to with a tenth of a percent N1. Any difference in fuel consumption is due to engine condition.

Right then, so it sounds like they should be sipping the same amounts, unless of course there were differing hours on the engines. One other thing I was wondering is would those engines send out an unscheduled "ping" if they shut down while the ac was still in the air. As in does it take a WOW switch or similar to shut off the pngers.

[Wilber]

I wouldn't be surprised if the engines had different times. When airlines get new aircraft they will do early changes in order to stagger overhaul times. That way they don't end up having to change them all at the same time.

It would depend on how many hours were on this particular machine.

Edited April 21, 2014 by Wilber

[WWWTT]

As far as I know there is no evidence of how the engines were shut down.

Therefore the pings do not indicate that the plane ran out of fuel then the plane crashed.

Thank you

WWWTT

[WWWTT]

There are several forums with B777 pilot explanations of what turns out to be a complex series of flight events upon loss of engine(s) power. Here is one scenario as seen in the simulator:

Thanks for the link BC!

I find it funny that someone who has never made the claim to be a pilot can add to the debate with some good links, meanwhile the alleged poster\pilots have no links to offer.

WWWTT

[WWWTT]

That's what I was thinking.

You're not the only one thinking.

Number one news story in the US!

http://t.news.ca.msn.com/world/why-are-americans-obsessed-with-missing-plane

WWWTT

[guyser]

The plane crashed and is in the ocean.

They will call off the search pretty soon and likely have sporadic attempts to look on the bottom of the ocean.

[On Guard for Thee]

Therefore the pings do not indicate that the plane ran out of fuel then the plane crashed.

Thank you

WWWTT

If you understood how the so called pingers woprk, you would know they can't tell you anything about crashing or not. In this instance all they are telling you is if the engines were running or not. When they did send the last ping they would have been getting close to fuel starvation in any case.

[bush_cheney2004]

Thanks for the link BC!

I find it funny that someone who has never made the claim to be a pilot can add to the debate with some good links, meanwhile the alleged poster\pilots have no links to offer.

It's all good....experienced pilots have offered their knowledge of multi-engine aircraft and flight deck procedures. I defer to their experience on such matters under normal conditions, and find interest in their qualified conjecture in this unusual case. The aviation "community" has a very well developed network of blogs and forums that informs the public with all kinds of otherwise unknown details.

I find some irony in the idea that the captain's flight simulator was rightfully seized as possible evidence of a crime, but the very same tool lets us explore many scenarios for what may have happened to this aircraft.

[Wilber]

Thanks BC, there are over 600 pages on this over at PPruNe but I am too lazy to go through them all. One thing I do know is that I know enough to know what I don't know.

PS. Don't know how I missed your quote. TAC eh! Nice. Wish they made them like that when I was still working.

Edited April 21, 2014 by Wilber

[Big Guy]

Just saw a special on CNN. It was an experiment on submerged cell phones. They took a cell phone, created texts, e-mail etc. Then submerged the phone in sea water (same makeup as the water the plane is probably in) for a couple weeks (I think). They then retrieved the now disintegrating phone, cleaned it up and used some scientific processes and was able to remove the memory chip. Then fed the chip into a reader and all of the data was still there.

If/when that airplane is found, the info on those cell phones may prove to be very informative.

[guyser]

Did they pressurize the tank ?

I have a sneaky suspicion those phones will not yield...easily.....much of anything

[On Guard for Thee]

Did they pressurize the tank ?

I have a sneaky suspicion those phones will not yield...easily.....much of anything

That pressure issue is important for sure. You probably already know this but at sea level we have about 14.7 psi of pressure on us. As you descend into the ocean, that doubles every 33 feet (1 atmosphere) so do the math on how much pressure that would be at 14000 feet or so. Crushing. If it equalized on the way down then maybe, but if the seal held that's a lot more pressure than any phone was designed to withstand.

[WestCoastRunner]

There was a 4 hour gap between when they lost communication with the plane and when they started a search. What were they thinking? Where was the military. I haven't heard of their justification for this lapse. Has anyone else?