Gentlemen: a serious question from a rotary pilot which may have an obvious answer that as yet escapes me:

In an emergency descent in reaction to an explosive (or other) decompression, what is the rationale for a major heading change?

This is one scenario I don't often find myself having to consider.

How do we know transponder was off if it was out of secondary radar area?

Edge... Traffic below on same airways . With GPS accuracy is such that you don't miss

Why would China release photos but do nothing? Surely they would want to be first on the scene to prove how capable their Navy is and because the majority of passengers were from China.

Dimensions.
 

I'm not buying the reported dimensions of the objects in the Chinese images as gospel, unless someone can explain specifically how they were derived. Given that uncertainty, all this imagery analysis on the news is baloney.


It seems as though the Media wants to keep the uncertainty going. Very shorty, surface and air assets will be on location, and we'll know; but I'll bet a nickel the Chinese have found it.

ABC News (Aust) states - "China said the objects were spread across an area with a radius of 20 kilometres, in sizes that appeared to be 13 x 18 metres, 14 x 19m, and 24 x 22m."

If the fuselage and wings opened out on impact, this would explain the large sizes of the items sighted. Those sizes eliminate sea containers.
Items were stated to be "floating", possibly just below the surface? Light refraction under the water could account for variances in size estimation.

Just watched the latest update on an US cable network... Honestly, some of the silliest posts on this board that the mods have deleted bear more weight than the crud they are dispensing

BTW: several posters have commented that they are required to switch the transponder from TA/RA to TA In the event of a depressurization.

There is a damn good reason to do this. If another aircraft is in your flight path as you hit the deck, and you are both in TA/RA the TCAS solution might be to have you climb ( not likely you're gonna do that ) and the other aircraft descend. IMHO, this is adding to the workload in an emergency, and I can't think of a reason a cabin baro switch couldn't do this for you...

Once we figure what happened, I DO think we as the aviation family need to kick some ideas around. Any step we can eliminate in an emergency procedure allows more time for the drivers to fly.

I do not see a conflict here - given the height of the satellite, resolution of optics, and angle of incidence, it's simple trigonometry. The satellite operator will know this fairly accurately. I believe the Chinese have calibration ranges in their western deserts for their imaging/spy satellites; if sophisticated satellite operator says this is the computed size, I'm going to give them benefit of the doubt.

Stanley11:
China Flyer: Aircrew react well to Standard Operating Procedures. Unfortunately, the challenge illustrated in the above quotes reveals a great difficulty that can arise when a maxim becomes a dictum! If you chant it, and act on it as though it was a liturgy, you can come unstuck. We live in a world where cosy soundbites rule. Alas this can all too easily undo the good that was intended by the snappy "Aviate, Navigate, Communicate" maxim.

Sure, there are three separate actions. Whilst I cannot conceive of removing AVIATE from top priority, if the motor skills you have acquired through experience prevent you from flying the aircraft AND paying heed to one or other of the remaining tasks, you must consider that you need help. Communicating this need would be good at this point in the proceedings. SHOVE the navigation task onto someone else: like ATC?

The terrain you are over might also make an early call for help desirable.

In an aircraft that has two pilots, two people sharing three tasks is easier than one person. Of course, if one of you has become incapacitated, then calling for help early takes much pressure off you!

Aviate, navigate, communicate ought to be viewed as a collection of requirements and not a by numbers drill.

There are two ways of problem solving: intellectually or procedurally.

An intellectual approach allows EVERY problem to be novel and brings a pilot's primary and background knowledge plus experience to bear to come up with a solution. All well and good.

Unfortunately, no two people will resolve a given problem in the same way. There will quickly come a time when some pilots will always be in demand, more so than others! In military or civil aviation, you have n aircraft and require n crews to operate them.

Standard Operating Procedures (S.O.Ps) came from military forces. S.O.Ps and the concept of checklists take the heat out of a situation by freeing the brain to cope with anything novel to deal with. Too many S.O.Ps makes the task difficult while people try to find the best-fit procedure.

If you're not careful, the "Aviate, Navigate, Communicate" maxim renders its execution a conundrum for rule-based people drilled in the concept of S.O.Ps.

Line of sight from rig
 

Post 2548 makes an excellent point... at 35000 feet, the distance to the horizon is ~229 miles, or 368 km. But, an object at 50-70 km at a heading of 265-275 degrees, as he reported, would be.

The point I see a conflict with is the current in the area; from what I have seen, the currents in the area would have moved debris to the SE of the crash site. The debris in the Chinese satellite pictures is SW.

Thanks to all for an excellent forum.

So what happens here:

Transponder fault forces AI flight to return to Delhi | The Indian Express

Does anyone have further details on recent transponder fault with AI 127 (another 777)

HEDGE 36
 

why the heading change?


if you are on an airway the presumption is that there might be traffic below you and if you descended while on course you might collide.

a 45 degree or 90 degree turn takes you off the airway and away from potential traffic.

HOWEVER

in many places where radar is quite good, like in the good old USA, a descent on the airway will be noticed by ATC and they will radio conflicting traffic and have them turn.

leaving an airway means leaving the safety of an MEA etc.

some airlines teach it, others don't. depends.


I hope this answers your intelligent question. one of the few I've seen here.

"Post 2548 makes an excellent point... at 35000 feet, the distance to the horizon is ~229 miles, or 368 km."

But the deck of an oil rig is well above the sea so you would have to add the sight distance from the rig to the horizon.

Add in refraction then it might well be possible to see at that distance.

And if currents took the debris away from the rig it could well have been closer than where it was found.

Not saying he did see it (could have been a meteorite) but that it does not appear to be completely impossible.

Neogen,

The plane will not go missing if the transponder fails. There are other means of communications as you might be aware of. This one is highly suspicious since it traveled additional milage..Or so we are told.

So is it possible that the transponder failed due to some reason ?? Then crew was busy in addressing that issue and in that process they failed to notice other emerging problems. May be just a simple case of poor resource management.

Then the question would be why didnt they communicate back ?

Aterpster (#2533) If that's the case (one singular and very robust loom running the length of the 777), then that would tend to support the theory. There would of course be a number of subsidiary looms running off that central wire bundle..... and they would tend to clump the wreckage in an apparent cohesive "whole" - as far as satellite imagery could discriminate. (see my post #2516).

#2548 Australopithicus and gruntpuddock #2566

but as I said in my post #2546 the wreckage was not at that point on the day of the crash, it was probably about "km" of 387km, and if you look at that it is about 70 miles from the rig, ( the distance estimated in the email was 50-70).

Look back and find the post with the prevailing currents and you will see they sweep down from G/Tonkin around tip of Vietnam and SW (in my original post I did say SE but meant SW)which is virtually the track from rig to wreckage.

If this is wreckage the guy on the rig saw the crash and it was on fire and had probably been out of control for a while before descending.

Dai_Farr
 

Forgive me if I you mistook "A,N,C" as the required processes, that must be followed every time there is an emergency.

That's not the case, and it is not what I was stating. The military-style "chant" is an easy way for younger minds to be taught what is important, and the order of importance. The more the sky gets filled with young pilots who have known nothing other than following the green/magenta line, the more important it becomes to remind them that they must fly the aircraft - when needed - to the exclusion of everything else, until it becomes safe to do other stuff.

In an emergency, the pilot must prioritise. If ATC can help you navigate whilst you aviate, that's fine: use them. But don't crash because you think you need to make a radio call..

Anyone know where to find the Malaysian press conference videos online?

Cheers

Isca...

It was my post saying that line of sight was impossible to the rig. Let me rephrase with elaboration: the formula for distance to the horizon is sq root of altitude x 1.23 for Statute miles.

Elevation is additive, so the extra 12.3 SM the observer gains from deck elevation is added to the aircraft to horizon distance

Can you explain again, in English, what your coordinates mean? "Km of 387" is cryptic to me.

llne of sight from the rig, assuming a deck height of 100' and a target of 35,000' is 392 km, but the aeroplane would be observed to be ON THE HORIZON. And that would need to be a spectacular fire to be seen from almost 400km away.

Factoring the reports of the aircraft descending from 35,000' it becomes impossible due to the earth's curvature

The Chinese images are from the day after the event, hence within a few km of actual impact, assuming drift.

In any event, I did not read any emphasis in the purported email about the sighting to be so low as to be on the horizon.

Shahidan to fly to undisclosed location to verify possible sightings.

KUALA LUMPUR: Minister in the Prime Minister’s Department Datuk Seri Shahidan Kassim confirmed that he will be flying to an undisclosed location late Thursday morning to verify possible sightings of the missing Malaysia Airlines (MAS) flight MH370.

Missing MH370: Shahidan to fly to undisclosed location to verify possible sightings - Nation | The Star Online