Malaysian Airlines MH370 contact lost

[tartare]

OK.
So the RMAF are now saying they didn't track it westbound?
I'm a little confused.
Without intending to irritate anyone, or appear callous in regard to the souls missing, transponder appears to be located on the pedestal next to the FO's left arm... tries to squawk 7700 while passing out and instead accidentally switches it off...?

[prayingmantis]

yep

Diego Garcia - now there's a place with limited radar capabilities!!! Surely they would have missed an incursion into their airspace

[grumpyoldgeek]

Without intending to irritate anyone, or appear callous in regard to the souls missing, transponder appears to be located on the pedestal next to the FO's left arm... tries to squawk 7700 while passing out and instead accidentally switches it off...?

Doesn't seem likely. The code change switches have a different and distinctive feel from the mode selector switch.

[Buster Hyman]

Anyone remember the three Ugly Sisters at QF, one developed a massive crack in the fuse which could have easily sent it to the bottom of the Pacific.

Very well, my Brother in Law was on that flight. (Assuming you mean the one where the O2 broke loose & ran amok in the cabin before exiting the fuselage). I thought of this in relation to the crew oxy & electronics location question. Massive damage from a rogue cylinder there.

[Old Boeing Driver]

Majorbyte

I lean to your theory, although we still haven't been able to rule out foul play, and that the airplane was taken for a reason.

[overthewing]

In all these posts, the only real facts known are that the transponder was turned off, the plane turned back, and descended, and was last detected by the military radar westbound until the signal abruptly disappeared.

Do we know that the signal disappeared, or simply left Malaysian radar range?

[flt001]

I've completely missed the source saying the military are retracting their statement that the plane changed track westbound. Anyone?

If true it fits into their PR mode of making some vague statement, leaving it one news cycle then retracting said statement.

[TURIN]

If for some reason, all electrical went out to lunch .. all of the major control surfaces might go to neutral? (remember, the 777 is the first fly-by-wire commercial jet) You'd be flying similar to the Sioux City aircraft without hydraulics? Only the engines to control left/right/up/down with? I think you'd have major problems with the up/down .. it might go into a phugoid oscillatory mode. Very difficult to control .. flying low .. you might get an idea of land/water to see where you were, but, you're cooked. You have to figure a place to land, and it's not going to be pretty. But, I'd think that there would be battery power for the critical items .. flight control computers, comm radios? Unless it was some sort of power surge throughout the system?

A320 was the first fly by wire airliner.

B777-You would still have engine driven and air driven hydraulic pumps running.

B777-Spoilers No.4 & No.11 have backup cable controls. So some roll control still.

[Willoz269]

This is baffling, at first I thought "up to 7 days before they find it"...now I am not so sure.

If reports are true that theaircraft turned back, it begs more questions than answers:

-Why was it no longer transmitting any comms, either radio, transponder, acars, nothing? (I would hazard a guess at fire onboard)
- What was so serious that necessitated a turn back?
- Why did they descend (if indeed eyewitnesses did see the aircraft), did they lose all instruments? all electrics, all displays, which explains loss of comms, etc as well?
- I was around 2AM...dark night, did they lose sight of mainland, no instrumentation, descended to get visual?

If so, this aeroplane could be absolutely anywhere.

[Old Boeing Driver]

Overthwing/flt001

The quote above in Post #1977 was what I was going by.

"the signal disappeared without any trace"

Was it because it got to end of their coverage?

I think this is the only "official" statement, but does not retract the westbound statement. (Maybe I read it wrong)

[GarageYears]

Until someone can convincingly explain how depressurization can be linked to the loss of the transponders... yes, there are two transponders in the T7, left and right, selectable via the transponder panel, it seems difficult to see how depressurization would lead to the transponders failing.

The external antennas are in different locations (though I can't find my reference to where exactly). Turning off the transponder isn't just a toggle or push-button, the switch is a rotary and you'd have to move it two positions to get it into the standby condition.

[mm43]

Another "expert" is now being quoted in the New Straits Times

According to him, the Under Water Beacon (ULB) can emit a signal for hundreds of miles but if the black box is covered with debris or falls into a trench at the bottom of the sea, then the strength and range of the signal would be lower.

For the record a Towed Pinger Locator (TPL) can only be expected to detect an operational ULB 37.5kHz signal when no more than 2 - 3km from its source. Ninety percent reliability is around 1,800 meters, and water temperature inversion layers can often create a variable outcome.

[wishiwasupthere]

First up, I'm not an airline pilot but a mere lowly GA charter pilot. But in the aircraft I fly, before changing a code on a transponder you turn it to standby. Is this the same in airliners? Following the path of some sort of catastrophic depressurisation, is it possible that Hypoxia dealt the crew it's fatal blow as they were in the process of changing the transponder code, hence it appearing to be turned off?

[Ranger One]

Originally Posted by Buster Hyman

Very well, my Brother in Law was on that flight. (Assuming you mean the one where the O2 broke loose & ran amok in the cabin before exiting the fuselage). I thought of this in relation to the crew oxy & electronics location question. Massive damage from a rogue cylinder there.

Negative, he's referring to an incident about ten years ago where a QF 744 was discovered to have a serious structural crack in the fuselage during a heavy check.

IIRC from the bumpf that circulated at the time, the crack was determined to have been caused by improper paint removal during an earlier repaint, using a metal scraper tool, which gouged the metal; the gouge then acted as a stress-raiser, precipitating the crack.

Someone correct me if I'm wildly wrong on the above?

[Old Boeing Driver]

Garage Years

That's the issue I keep coming back to.

A few posts ago, someone asked if the transponder could be turned off in the haste of changing codes in an emergency.

The response was that the knobs have a very different feel.

I lean the same way. I think it was turned off manually.

Why was the transponder turned off?

[JamesCam]

GarageYears :

'Turning off the transponder isn't just a toggle or push-button, the switch is a rotary and you'd have to move it two positions to get it into the standby condition.'

True, but you are supposed to go to standby before changing the code, so possibly he forgot to switch it back on or passed out before he'd done so.

That said, I don't believe the above scenario to be the cause of the failure, it doesn't appear to be just the transponder that went quiet..

Edit: Sorry wishiwasupthere: missed your comment saying the same thing...

[Ex FSO GRIFFO]

Question...
What is the RADAR facility / range at FJDG, anybody?
Track from 'disappearance point' to DG is approx 245T, and quite within the fuel range..?

Just curious.....

[GarageYears]

OBD... and I'll add that I don't think they could be turned off "accidentally" even in a hypoxic state. The mode control knob is completely different from the code rotary.

[Old Boeing Driver]

Trqnsponder

I have never flown an airliner, and I can't remember any corprate jet where you had to switch the transponder to standby before changing codes.

Some corporate jets actually have a control wheel button that changes the squawk to 7700 if pushed.

Not saying some don't require this, just none I've seen. Don't mean to sound rude.

[pigboat]

I have never flown an airliner, and I can't remember any corprate jet where you had to switch the transponder to standby before changing codes.

The idea of switching to STBY between codes was to avoid inadvertently hitting a 7000 code during the code change.