The use of the word transponder is causing confusion here. There is the Mode S transponder referred to above, there is also the Mode A/C transponder which is the 4 digit SSR transponder.

FNG here. Private Pilot and aircraft owner-PA-28. It is good to see that there are some real experienced folks here, adding good info and not just crazy conspiracy theories.

As for transponders, every aircraft registered, at least in the USA, has a unique transponder address assigned, whether a xpdr is installed or not. For instance, my PA28 has a Mode C transponder, which as far as I know does not broadcast any identifying info other than whatever code I have dialed into it. AFAIK the address code is reserved for future use. Of course in the airline and commercial world where more sophisticated xpdrs are required (and soon for GA too, with the impending ADS-B requirements), the address is coded in and transmitted on the extended squitter.

As far as simming goes, at least in the GA world I hear it is getting quite popular as a tool to maintain skills when one can't fly as often as one would like. My CFII has said he uses FSX as a tool to brush up on instrument procedures, and recommends it to his students. I personally fly XPlane 10 a lot to keep up when the weather keeps me grounded (still working on my inst rating and of course a PA-28 is not certified for flight into known icing). Simming is a tool that I would bet a lot of commercial and ATP pilots use for fun and informal training, nothing inherently suspicious there.

ex-EGLL;
Does the T7 have both?

A number of posts suggested that all those dense jungles in SE Asia could easily hide a small smoking hole. Let me remind everyone that the romantic picture of dense jungles (with aeroplane wrecks overgrown with trees waiting for Indy) is a thing of the past. The region has one of the highest population densities of the world, and more than 90% of the original primary forest cover is gone, to be replaced by farmland, palm oil plantations, and second-growth forests after logging. Even in mountainous areas where the forest canopy appears continuous, there is a dense pattern of small farms and villages. I find it inconceivable that a T7 could have landed or crashed anywhere on any land within range (except small uninhabited islands in the Pacific and Indian Oceans, but those are not many) without being heard or seen by somebody.

How Far It Flew
 

Kerosene Kraut:

The SecDef of Malaysia denied the engine data transmission story today. The US still seems to support some ongoing flight theory.

Its not that Malaysians are against the ongoing flight theory, till someone locates the debris field you have no option but to assume that the aircraft flew beyond that geographic area. Right now they are scouring Malacca strait and eastern Andaman Sea. In next couple of days they will move further west into the Bay of Bengal and Indian Ocean. Its pretty obvious by now that the debris field is not anywhere close to main shipping channels in the Indian ocean but perhaps further north in the Bay of Bengal.

According to ABC's chief Pentagon correspondent, the U.S. is sending the USS Kidd from the Andaman Sea west into the Indian Ocean, and it will take the ship 24 hours to get to the area where the U.S. thinks the plane might be.. Cruising speed could be 33 knots.

For the rapid decompression theorists here are some facts from RAF AVMED.

Hypoxia (anoxia) occurs when the body is short of oxygen.

Amount of oxyhaemoglobin in the blood depends on the amount of oxygen in the lungs (not atmosphere).

Partial Pressure of Oxygen

At sea level the standard atmospheric pressure is 760 mmHg. 21% of 760 will be from Oxygen because amount of oxygen in the air is 21%. Thus partial pressure of oxygen in the atmosphere at sea level is 160 mmHg. The amount of oxygen in the air can be described as its partial pressure in mmHg. As altitude increases the partial pressure of oxygen in the atmosphere falls. The rate of change of pressure is greatest as we climb from sea level and decreases with altitude.

At sea level, percentage of oxygen in the lungs is only 14.5% (in atmosphere it is about 21%). Thus the partial pressure of O2 in the lungs is 100 mmHg.

As altitude increases the partial pressure of oxygen in the atmosphere falls but the proportion of oxygen in the atmosphere remains the same. Also as altitude increases the partial pressure of water vapour and to an extent carbon dioxide in the lungs remains the same reducing the partial pressure of oxygen in the lungs still further. Reduction in cabin pressure to an equivalent altitude of 8000 ft (65 mmHg partial pressure of O2 in lungs) produces a detectable impairment of mental performance. Healthy people are able to compensate for altitudes up to 10,000 to 12,000 ft. Above this, risks become serious. Short term memory is affected early on.

At 18,000 ft the partial pressure is 50 mmHG (half that at sea level).

Unconsciousness occurs at about 35 mmHg of oxygen in the lungs (equivalent to prolonged exposure to altitudes between 20,000 and 25,0000).

Air can be used up to 10,000 ft. After that it needs to be mixed with oxygen up to 33,700 ft. Above this 100% oxygen upto 40,000 ft.

Above 40,000 ft 100% oxygen alone is insufficient and it must be supplied under pressure to the oxygen mask. This is pressure breathing.

Hypoxia does not lead to shortage of breath. If the oxygen supply system fails the normal reaction to lack of oxygen, "Panting" does not appear because, there is no excess of carbon dioxide.

Onset of hypoxia is insidious (like CO poisoning) and can be recognised only by being very aware of the symptoms.

Symptoms of Hypoxia:

Concentration difficulties.
Impaired judgement, mood changes, euphoria (euphoria can be experienced above 10,000 ft).
Drowsiness and lethargy.
Light headedness, dizziness, nausea.
Loss of muscular co-ordination.
Pallor and cyanosis.
Failure of the basic senses, especially colour vision, which becomes affected by 8000 ft. Night vision affected above 8000 ft.
Unconsciousness, coma and death.

Following factors increase the onset of hypoxia:

Exercise
Cold
Illness/age
Fatigue
The use of drugs/alcohol
Smoking. It can raise the physiological altitude by 4-5 thousand feet above the actual cabin altitude as the ability to transfer oxygen is reduced by 4% to 10%.

Time of Useful Consciousness

It is the length of time during which an individual can act with both mental and physical efficiency and alertness. It is measured from the moment at which an individual is exposed to hypoxia. It varies with altitude and these are the relevant levels believed to apply in this case

Altitude in ft .......... Time

30,000 .................. 30 seconds to 1 minute

35,000 .................. 15 to 30 seconds


Time of useful consciousness for people doing light to moderate work (effective performance time) falls by 40%.

Time of useful consciousness for people already short of oxygen (flying at a cabin altitude of 8000 ft) are half of the above values.

Can any 777 pilots confirm the cabin px at cruise altitude of 35,000ft? I know from my time as an FE that in many aircraft it's in the order of 5000 to 8000 ft so even before a failure all occupants are partially suffering from hypoxia.

Not a theory just some facts to help the discussion along.

Pentagon have just told ABC News that they are of the opinion mh370 went down in the Indian Ocean.

They are so confident that they are repositioning USS Kidd to the area to start a search

I believe that in the case of Swissair 111 the range of the acoustic pinger was reduced due to being deeply embedded in the debris, the entire aircraft was in very small area.
BTW The idea of a check of local Seismic records sounds like a good one.

The FlightID can be selected/changed in the cockpit via the radio management unit, FMS or by a dedicated control head - depending on the aircraft model. Part 121 operators typically set this to the flight number of the specific scheduled flight.

The mode S ID however can NOT be changed by the flight crew. This is a unique 24-bit number derived from the aircraft's registration number, and is hard-wired into the transponder mounting rack. Changing it (typically) involves moving wire jumpers on a programming plug, and can only be done on the ground by maintenance engineers.

The mode S ID is hard-wired in this way so that if the transponder has to be changed, the replacement unit will automatically assume the correct ID, merely by being slid into its mounting tray.

Could I just ask if anyone knows or has any experience in what level of equipment is being used to sweep the seabed? I presume the search teams are scanning the sea floor for debris and not just concentrating on the surface? It's not the deepest water in the world. Can under water devices cover a large area or is it a slow process to search an area in detail enough to detect parts of aircraft? I'm starting to wonder if any things been missed, particularly in the vicinity of the last known position.

To answer a question posted earlier, No there is not a separate A/C transponder. The mode S boxes transmit A C and S.

There are 2 strapping modules in the avionics bay that hard code the aircrafts registration number for the transponders.

Thank God altimeters are not calibrated in mmHg, I had enough trouble changing from 1013.25 to 29.92:O

Malaysian official said they contacted rolls Royce and Boeing and both said their data stopped at same time as Malaysians... that should put a stop to the 4 hour engine data saga, there is no way that both those companies would keep quiet if someone else was telling porkies about their companies!!

Haystack
 

Yes but it would be a good idea if someone could first find the 'haystack'

U.S Reports "indications"
 

What type of "indications" would they be referring to that no one else was able to obtain.

A resume of the research :

"here
no there
it went eastbound
no no westbound
oh here some fuel trace
no no, it's from a boat
arfff
oh here some debris!
no no it's not
it was on its route
no no it flew off route
let's search on the west side
oh here a raft
no it's not
oh! here a debris 18/20m
no no it's a joke by chinese
arrff
let's go to Indonesia then."

:ugh::ugh::ugh:

Fly26:
Basically, two things. They are listening for the flight recorder sonar pinger and also using active sonar, including side scan.

One problem with sonar is that the coverage tends to be fan shaped. The deeper the water, the broader a path they can cover on the bottom. The waters where contact was lost aren't very deep. So the strips of bottom covered per pass won't be very wide. On the positive side, the nature of the sea in the search area rules out things like thermoclines and other phenomena that could blind sonar.

If by some chance MH370 made it East to the Philippines or West of Sumatra, there are some deep drenches and rougher bottom terrain to deal with.

406 ELTs send out a test message for 45 seconds before they go into the crash mode and trigger alarms. It IS possible that the ELT went off for a few seconds before it became separated from its antenna. That test signal might be logged somewhere

It's a hope anyway. At this point the only thing I know for sure is that it is not at KBVU.

Malaysia is the Last to Know
 

This is a big scoop for ABC news. Author is Martha Raddatz, absolutely impeccable sources and credentials, great, seasoned reporter.

What's becoming clear to me is that the U.S. (Pentagon and NTSB at very least) have better intel than the Malaysians, and, to protect the extent and sources of such data for reasons of national security and international relations, have had to find back-channel ways (the NTSB radar "advisors," NASA, etc) to leak the correct location of the aircraft to the Malaysians so as to seem to have them organically find it.

Unfortunately, with Vietnam etc. making good-faith efforts and taxing resources in a humanitarian gesture, the U.S. can't wait, sources are leaking to hurry this up. You can bet that was okayed at the highest levels and we have been talking to China.

My current theory is that the plane was hijacked but that the pilot flew it out into the ocean rather than to the specified destination.

This also helps explain why Greg Feith, well-respected former NTSB investigator, was on air recently floating the turn-back/hijack scenario. At the time I thought he'd lost his bearings in all the media hype. Maybe more likely he had inside info.

http://www.nbcnews.com/storyline/mis...inquiry-n51036

Tom Costello, NBC, is saying USS Kidd is heading to the Strait of Malacca NOT the Indian Ocean.

So we have two main media sources saying different things...again. Perhaps everyone needs to just slow down a bit. Chaotic information releases.

RG:
From what an airline source/Malaysia press conference previously released:

(1) They do not appear to have the sattelite option for ACARS, using the VHF option instead.
(2) They apparently did not exercise the "Boeing tracks our ACARS" option in their support contract with Boeing.

Some pages back, a PPRuNer provided a map with a series of notional, overlapping VHF range circles and ground station locations to give an idea of where you would expect to see ACARS(VHF) be able to receive data from an aircraft in flight at cruise altitudes. You can see that there is a bit of a gap west of Thailand. IF, as also discussed in this thread, the RR data system only sends info when something changes, as opposed to "every x number of minutes," then it is very plausible that no message was sent until the plane was in that gap, IF that gap is where it ended up. As you can see, there is a lot of "IF" going on there.

Beyond that, no comment on why Uncle Sam thinks the bird went down in the IO.

Wait. Two questions.
First. Can you please provide a link for this information?

And second. Then why is the aircraft being searched on Indian Ocean? How can the ACARS datalink have stopped at the same time as the aircraft went off radar and the same aircraft have flown hundreds of miles West without transmitting any downlink?

Would someone please care to explain?

Pinch of salt...
 

There have been so many leaks, which have then been dismissed by the Malaysians, that it's easy to start taking a pinch of salt with every new tidbit that pops up. Even so-called reliable media sources have seen their sources dismissed.

So what, if anything, do the US know that led them to redeploy the Kidd at top speed?

New search grid
 

http://i.imgur.com/FVG3C69.jpg
Source: The Telegraph

JMO, of course, but I think that high level politics is going on here. Civilian unrest meets DHS, whether of the USA, or China, or another sovereign state. Given the sophistication of modern military science, I think one or all know what happened, and where it is, and figure that high level security requirements take priority, and since they're all dead, they don't care. Let everybody run around like headless chickens, that's the price. JMO, as I said.

If MH370 turned west from its last known position and, if it passed close to Pulau Perak as reported earlier by the Malaysian authorities, it would be on a track of 255 degrees (approx.). If it had enough fuel for 3000 nautical miles it could have come down about 200 miles south of the Seychelles.

A lot of "ifs", I know, but is this the scenario the Yanks are investigating?

Barrel_owl
 

If, and it's a big IF, the US is onto something in the Indian Ocean, then a whole lot of questions suddenly pop up, don't they?

Like how come RR and Boeing apparently have no data supporting the theory?

Like why the heck they've wasted 5 days searching an area where they seem to think the aircraft didn't go down?

Like who is actually directing the SAR ops?

And many more...

If it is found in the Indian Ocean, I along with quite a few others have stated that it might be there on this thread, obviously a hunch. Depressurisation would be the main candidate if it was found to be there I would have thought. The Malaysians might be in for an even rougher ride if MH370 flew straight back over their heads during the incident and rightly so.

EEngr
 

Thank you for the information, I was trying to figure out how accurate the search was, so in theory if it was there they would have come across it. If the decompression/hypoxia/reciprocal heading theory that many people suggest is anything to go by the MSAs around North Sumatra are high up to 13400, that terrain could hide an aircraft as well. It took a while to locate the sukhoi crash although weather did play a part hampering the search.

The search area given by The Telegraph would make sense if it was established that the unidentified radar contact heading west was not picked up by Indian primary radar on the Andamans or Nicobars. The logical thing would be to comb that radar coverage gap in the middle with no primary radar coverage from either side.

If the "UFO" diverted to the SW (direction Diego Garcia) in that potential radar gap nobody would have noticed. Such a hypothetical diversion would bring into play the Pentagon. In Diego Garcia there must be some impressive surveillance equipment, AWACS and the like. Maybe something was picked up there ?

I was about to ask the same thing.

Both Boeing and RR deny receiving any ACARS and either they are lying or telling the truth.
If they are telling the truth there is a third possibility: that ACARS was being sent but they didn't receive them.

Otherwise, why is this Destroyer being deployed at high speed to what should be the wrong position.

That one is easy. Either a US sub or a US sub killer picked up the ping.

How feasible is this scenario?
 

To those who fly/work on 777s... How feasible is this?


1. Rapid decompression caused by exploding crew oxygen tank, or decompression aggravated by fault in cockpit oxygen tank/line;
2. Pilots don masks but there is no oxygen flowing and they aren't aware;
3. Pilots initiate descent and course reversal but mess up the interaction with the MCP and command FL295 instead of FL100 or similar;
4. Pilots become incapacitated within 30-60 seconds (time of useful consciousness as per source - http://www.casa.gov.au/wcmswr/_asset.../nov/20-23.pdf);
5. Incapacitated pilots inadvertently turn transponder to off or standby;
6. Pilots go unconscious as plane flies towards Andaman Islands/Bay of Bengal;
7. If spoilers had been deployed, A/T commands sufficient thrust to maintain (or attempt to maintain) MCP altitude and override effect of spoiler deployment;
8. Aircraft at near-max thrust runs out of fuel much more quickly than aircraft at cruise thrust, falls into the Bay of Bengal between Andamans and India/Sri Lanka.


What technical factors support or invalidate the above chain of events?


Thanks for all the input...

Why would the US need to BS for a few days if they really knew where it was at? Does anyone really doubt the level of technology the US Government has available to them worldwide? Would it really be that damaging to the US intelligence community for them to say "we know where it's at, we'll tell you where, but we're not going to tell you how we know"?

I don't have a link but I just heard audio on the top of the hour news break on NPR from the Malaysian government's press conference where they said they have spoken with Boeing and Rolls Royce and there was no data from the plane beyond when it dropped from radar.

Yes and No.

The United States Navy has four Ohio class ballistic missile submarines on patrol at any given time, the United Kingdom has one Vanguard class ballistic missile submarine on patrol at any given time and France has one Le Triomphant class ballistic missile submarine on patrol at any given time, giving the US and its NATO allies potentially six submarines that could have detected wreckage.

Their patrols, routes etc are highly classified and none of the three nations would admit that one of their ballistic missile submarines was in the area, hence the way this might be being played out. There is even a possibility, especially in the case of the US, who are more likely to have one submarine in the area, they've sent one of their submarines to look in some deeper water, and they'll worry about explaining away any questions later.

AWACS are far and few, not usually in that area
 

They rarely are in that area and wouldn't be in an air defense role unless there were an active operation.

New search area in Indian Ocean

It seems that the White House is better briefed than the Pentagon press office. Jay Carney, the White House spokesman, has just confirmed thata new search area*may be opened in the Indian Ocean, reports the Guardian’s Paul Lewis in Washington.“It is my understanding the one possible piece of information, or pieces of information, has led to the possibility that a new search area may be opened up over the Indian Ocean,” Carney said, without detailing the nature of the new information.He said discussions were ongoing with international partners to “deploy the appropriate assets” in any new search in the Indian Ocean. He added the new search would be based on “additional information” that was not yet “conclusive”.His comments appear to*confirm that earlier story*by ABC’s Martha Raddatz.

29.92 is inches of mercury, whereas 1013.25 is mbar (obsolete unit).

1 bar = pressure exerted by a force of 1 kilogram-force over a unit surface area of 1 square centimeter.

The official pressure unit is now the Pascal : 1 Newton over 1 square meter, hence 1 bar = 100 000 Pascal, 1mbar (millibar) = 100 Pascal aka 1 hPa (hectopascal)

Missing Malaysia Airlines flight live: Satellites picked up 'electronic ping' from missing flight MH370 after it lost contact with ground control - Daily Record

More details now on the 'electronic ping'.

A source close to the investigation said communications satellites picked up faint electronic pulses from Malaysian Airlines Flight 370 after it went missing on Saturday.

However, the signals gave no indication about where the stray jet was heading nor its technical condition.

The "pings" equated to an indication that the aircraft’s maintenance troubleshooting systems were ready to communicate with satellites if needed, but no links were opened because Malaysia Airlines and others had not subscribed to the full troubleshooting service, the source said.