#MH370 - What happened? Your theories?DT notepg17 - Page 29

Originally posted by: -MakhanMalaai-

Okay why did it fly for four hours? I still have a feeling the plane is being held hostage somewhere.. I don't know what they're planning.. maybe something big..

Originally posted by: mayumi

I had a doubt regarding the chip makers on board ever since I heard the story. Could they have been carrying and testing a new system of some sort. There are Indians among that list of designers. They should question Free Scale about thier projects.

Originally posted by: .Elixir.

Another theory. Good read.

[quote]What happened to MH370?

Has anyone considered if the below FAA Airworthiness Directive could be a clue the MH370 investigation?

A November 2013 FAA Airworthiness Directive for the 777

http://www.gpo.gov/fdsys/pkg/FR-2013-09-26/html/2013-23456.htm

SUMMARY: We propose to adopt a new airworthiness directive (AD) for

certain The Boeing Company Model 777 airplanes. This proposed AD was
prompted by a report of cracking in the fuselage skin underneath the
satellite communication (SATCOM) antenna adapter. This proposed AD
would require repetitive inspections of the visible fuselage skin and
doubler if installed, for cracking, corrosion, and any indication of
contact of a certain fastener to a bonding jumper, and repair if
necessary. We are proposing this AD to detect and correct cracking and
corrosion in the fuselage skin, which could lead to rapid decompression
and loss of structural integrity of the airplane.

Update 3/12, 16:43:

It has been brought to my attention that this specific Malaysian Airlines aircraft

"9M-MRO, the aircraft operating MH370, was not equipped with the SATCOM antenna affected by the airworthiness directive."

However, this does not discount the possibility that the aircraft flew for hours (on autopilot) after a decompression event. (The 777 had an early history of decompressions when the first planes were rolling off the assembly line in 1995.)

There may be other high-risk fuselage seams that could have worn out and affected radio equipment (and/or pressurization). There are also many low-level circuits, sensors, and valves related to pressurization could have malfunctioned. (e.g. Air/Ground sensors/circuits, an "air duct clamp", etc.).

Ultimately, some type of decompression"slow or rapid"is still likely in this situation, given the lack of clear communication from the pilots.

[Updated] Summary: It seemed likely that a fuselage section near the SATCOM antenna adapter failed, disabling satellite based - GPS, ACARS, and ADS-B/C - communications, and leading to a slow decompression that left all occupants unconscious. If such decompression left the aircraft intact, then the autopilot would have flown the planned route or otherwise maintained its heading/altitude until fuel exhaustion.

A slow decompression (e.g. from a golfball-sized hole) would have gradually impaired and confused the pilots before cabin altitude (pressure) warnings sounded. The also likely possibility of an extremely-rapid decompression is described toward the end.

Chain of events:

• Likely fuselage failure near SATCOM antenna adapter, disabling some or all of GPS, ACARS, ADS-B, and ADS-C antennas and systems.
• Thus, only primary radars would detect the plane. Primary radar range is usually less than 100nm, and is generally ineffective at high altitudes.

If the decompression was slow enough, it's possible the pilots did not realize to put on oxygen masks until it was too late. (See Helios 522)

• Also explains why another Pilot thirty minutes ahead heard "mumbling" from MH370 pilots.
• (VHF comms would be unaffected by SATCOM equipment failure.)

With incapacitated pilots, the 777 could continue to fly on Autopilot - programmed to maintain cruise altitude and follow the programmed route. Using the Inertial Reference System (gyroscope based), the plane could navigate without needing GPS.

Other thoughts:

• The plane was [UPDATE: WAS NOT] equipped with cellular communication hardware, supplied by AeroMobile, to provide GSM services via satellite. However this is an aftermarket product; it's not connected through SATCOM (as far as I know).
• [UPDATE]: However, if the plane flew over or near land, then cellular connectivity is still possible.
• Interestingly, 19 families signed a statement alleging they were able to call the MH370 passengers and get their phones to ring, but with no response.
• When Malaysian Airlines tried to call the phone numbers a day later, the phones did not ring. By this time, fuel would have been exhausted.

Note: 777 Passenger Oxygen masks do not deploy until cabin altitude reaches 13,500. Passengers were likely already unconscious by then, if it was a slow decompression. Also remember that this flight was a red-eye, most passengers would be trying to sleep, masking alarming effects of oxygen deprivation. No confirmed debris has been found anywhere near the search area, consistent with the plane having flown for hours after it lost radar contact.

[UPDATE 3/12]:

Issues of Decompression:

The flight probably did not experience an or "inflight breakup" or "explosive decompression" that caused the plane to just "fall out of the sky."

Instead, it's more likely that a non-catastrophic decompression incapacitated the crew. It could have been a slow decompression. (This scenario is more likely if the "mumbles" observed by another MH pilot are legitimate.) It could have also been an extremely rapid decompression, forcing the lungs to exhale more rapidly than they are capable of. Either type of decompression makes it difficult for the crew to respond before becoming incapacitated.

This table from Carlyle shows that after a moderately rapid (2-6 second) decompression at MH370's cruise altitude, the crew would have had only 30-45 seconds of useful consciousness unless they started oxygen breathing soon enough.

For all 3 types of (slow, moderate, extremely-rapid) decompression, there is substantial danger to the crew and passengers.

Provided the overall structure of the plane was still intact at the time of a decompression, the autopilot would have continued along the route autonomously. In order to descend to 10,000 feet, the autopilot must be commanded to do so or disengaged entirely.

So why does all this matter?

The aircraft may be at the floor of the East China Sea, Sea of Japan, or the Pacific Ocean thousands of miles northeast from the current search zone. [UPDATE: Basically, it could be "anywhere", and we need to use any available radar records to help figure it out. It could have turned in any direction and continued on for hours. This is where the Vietnamese/Malaysia civilian and military radars will help.]

Recommendations:

• Investigators should obtain data logs from primary radars throughout mainland China that would have been along the planned route. They may be the best clue as to the trajectory of the aircraft.
• Investigators should obtain all passengers' cell phone log and location data. The timing of the last successful cellular connection (ring/SMS/data-packet) can predict how long the plane was in the air. iPhone/iOS location (GPS) data may be available from Apple if subpoenaed. Android location data may be available from Google.
• Add a secondary search space to include a 300nm+ radius around Beijing, focusing on surrounding bodies of water. Using planned routing trajectory, known autopilot logics, fuel quantities, and weather patterns, it may be possible to define a smaller 50nm * 50nm search space. Consider running the above scenario in MH's 777-200ER full flight simulator.
• Boeing should provide expertise about fuselage/antenna seam reliability and autopilot/navigation logic, so as to help plot this second search space.
• http://mh370lost.tumblr.com/post/79214607814/what-happened-to-mh370[/quote]

The Malaysian Airlines flight 370, which has been missing for the last six days, could have flown on for hours after the time it reached its last confirmed location, suspect American investigators, according to the Wall Street Journal.

What this means is that the plane could have flown on for hundreds of miles more under conditions that remain murky', the newspaper said.

On the basis of data automatically downloaded and transmitted to the ground from the widebody plane's engines as part of a routing maintenance and monitoring programme, the newspaper reports that the investigators believe that the 777 could have flown on for another five hours.

In that time, the plane, which left Kuala Lumpur for Beijing and went off the radars one hour later, could have covered a distance of about 2,200 nautical miles, and could have reached as far as the border of Pakistan, say, or even the Arabian Sea, the WSJ reports.

The report further says that American counterterrorism officials are probing whether the pilot or anyone else on board the aircraft could have forced the plane to another destination - after switching off the aircraft's transponders to evade detection by radars.

So far, officials have neither confirmed nor ruled out the possibility of terrorism being behind the plane's disappearance.

However, the report adds that at one briefing, officials were informed that the investigation was looking at whether the plane was deliberately diverted with the purpose of using it later for other purposes - terrorism being the obvious motive.

The one sureshot way of finding out the plane's flight path is the engines' onboard monitoring system which regularly transmits data about the engine health and aircraft movement to Malaysian Airlines which, as part of its maintenance agreement shares it with engine manufacturer Rolls Royce for analysis.

Now investigators, it is said, are studying this data to find out the plane's flight path after the transponders were switched off. The plane, which was headed for China, was last visible on radars around the Gulf of Thailand.

In all, 56 ships were taking part in the search for the aircraft, , with Malaysia providing 27 of them. Plus, 30 aircraft were also on the lookout for the missing plane. However, the challenge, the WSJ quotes Lt David Levy, a spokesman for the US Navy's Seventh Fleet as saying, isn't so much coordination as the sheer size of the area involved'. The search grids are up to 20 miles by 120 miles, and ships and aircraft employ an exhaustive methodical pattern "like mowing your lawn" in their search for the plane, he said, the newspaper reports.

Image: Clouds hover outside the window of a Vietnam Air Force aircraft AN-26 during a mission to find the missing Malaysia Airlines flight MH370 ' Photograph: Kham/Reuters

Originally posted by: goral100

The Airworthiness Directive you reference did not apply to the Malaysia Airlines 777 in question. It was equipped with a different satcom arrangement. Also worth noting is that the cockpit crew would have been amply warned of any slow to moderate increase in cabin altitude (depressurization or over pressurization) well before it got the the point of incapacitating anyone. Airplanes fail to pressurize or, in general, have cabin pressurization issues at times. More than people might think, honestly. Procedures for such scenarios are trained for the safety of passengers and crew.
Satcom on Malaysia's 777s is manufactured by Honeywell and uses a different antenna arrangement. Malaysia had the units installed after delivery from Boeing. Different antenna than the one referenced in the FAA AD and by the author of this piece. I can't make this any simpler than to advise that you look at a 777 that has the Boeing factory satcom system referenced as the "suspect" antenna in the airworthiness directive (Singapore Airlines and American Airlines are two carriers that have it installed) and then try and find the same antenna on any of Malaysia's 777. You won't...because it isn't there...because it was never installed...so there is no chance for the associated fatigue cracking...because AGAIN this airplane didn't have the antenna...so this theory is junk.