Posted on 03/15/2014 2:24:35 PM PDT by nickcarraway
If multiple communication systems aboard Flight 370 were manually disabled, as investigators increasingly suspect happened, it would have required detailed knowledge of the long-range Boeing777's inner workings.
The Wall Street Journal said the first loss of the jet's transponder, which communicates the jet's position, speed and call sign to air traffic control radar, would require disabling a circuit breaker above and behind an overhead panel.
Pilots rarely, if ever, need to access the circuit breakers, which are reserved for maintenance personnel.
Pulling one specific circuit breaker, which is labeled, would render inoperative both of the 777's transponders, according to documents reviewed by WSJ and bolstered by comments from aviation industry officials and those who have worked with the 777.
Becoming familiar with the 777's systems requires extensive training for pilots and aircraft mechanics alike, experts said. However, considerable technical data on the airplane is also available online in discussion groups or other websites.
Investigators are trying to establish a sequence of events that transpired on the jet, which vanished from radar March 8, most critically the loss of communication.
The shutdown of the on board reporting system shortly after the jet was last seen on radar, can be performed in a series of keystrokes on either of the cockpit's two flight management computers in the cockpit.
The computers are used to set the performance of the engines on takeoff, plan the route, as well as other functions to guide the 777.
After vanishing, the jet's satellite communications system continued to ping orbiting satellites for at least five hours.
The pings ceased at a point over the Indian Ocean, while the aircraft was at a normal cruise altitude, say two people familiar with the jet's last known position.
Investigators are trying to understand that loss, and whether or not "something catastrophic happened or someone switched off" the satellite communication system, says one of the people.
The longest week
A physical disconnection of the satellite communications system would require extremely detailed knowledge of the aircraft, its internal structure and its systems.
The satellite data system is spread across the aircraft and disabling it would require physical access to key components.
Disconnecting the satellite data system from the jet's central computer, known as AIMS, would disable its transmission. The central computer can be reached from inside the jet while it is flying, but its whereabouts would have to be known by someone deeply familiar with the 777.
Getting into the area housing the 777's computers would "not take a lot" of knowledge, said an aviation professional who has worked with the 777.
However, this person added, "to know what to do there to disable" systems would require considerable understanding of the jet's inner workings.
Some airlines outfit the access hatch to the area below the floor with a special screw to prevent unauthorized intrusion, the person added.
Orbiting satellites are designed to check in with the aircraft's satellite-communication system hourly if no data is received during that time.
The pings from the aircraft became a subject of scrutiny earlier this week, said a person familiar with the matter, several days after the plane first went missing.
Because the pings between the satellite and the aircraft registered that the aircraft's satellite communications system was healthy and able to transmit, the data did not immediately raise any red flags in the hours after the jet's disappearance.
At first, the origin of the final ping from the Malaysia Airlines jet seemed like an anomaly to investigators, according to a person familiar with the matter, given that the plane was believed to have crashed off the coast of Vietnam, hundreds if not thousands of miles from the location of the final ping.
What is a transponder? Until just a few years ago, the satellite communication system used by jetliners didn't include data on an aircraft's location in the pings, the electronic equivalent of handshakes used to establish initial contact.
For instance, before Air France Flight 447 crashed into the Atlantic Ocean in 2009, the jet sent some diagnostic data indicating problems with various onboard systems, including the autopilot's deactivation. But notably the plane's position wasn't transmitted with that data.
Partly as a result it took nearly two years to locate the plane's "black boxes" and the majority of the wreckage. In the case of the missing Malaysian jetliner, precise locations were provided. However, it is unclear why the transmission ceased and where the plane may have ended up after the final ping.
An expert would be needed to disable the systems on the missing Malaysia Airlines jet. The headline to an earlier version of this story incorrectly said an insider would be needed.
When I read the names of the two pilots, I knew immediately that the Religion of Peace already had control of that plane....
Records should show how much fuel was loaded on the plane.
The argument against the northern route is they couldn’t have reached it without being noticed. Absent some late announcement that Nepalese, etc. radar had seen them that argument fails IF they went north. It may be incompetence in which case someone’s superiors had better at least feign outrage. Or it may be their defenses, optimally run, aren’t as good as advertised, in which case someone’s taxpayers may be outraged. But if there are merely cracks in their systems, which MH370 exploited, there may be clues in how they learned such and there may be clues to their path and current position in discovering those cracks. It’s another angle on a problem for which we have little data. The US Air Force and Navy should contain folks able and willing to differentiate amongst those possibilities. If they don’t, even after 5 years of Obama, I’m outraged.
When I first saw a photo of the pilot (not the co-pilot), I knew he was guilty. A photo of the pilot, I read, is posted on facebook.
This part is true: flies the plane toward Mecca
“I think a bigger problem is that cellphones go out of range. Once they are off-shore, and 20 or 30 miles from a celltower, they do not work.”
That is all out the window. As it does not work that way. While on the plane cell phones communicate with the planes communication system. The plane then talks directly with a satellite which then communicates with the ground phone system. So in essence the plane itself is a cell tower. It is this system in the plane that sent all the final pings to the satellites. And it also explains the actual communication with cell phones that were still turned on when loved ones tried to call in.
It is possible that the cell phones were collected by terrorists. It is also possible that all normal passengers were already dead according to some theories.
See my last post. There is no such thing as being out of cellphone range.
My suggestion: get the email address and cell number of every passenger. Then check for any outgoing messages .
You are correct. Cell phone signals are high-UHF or near microwave and are almost pure line of sight. From 35,000 feet line of sight is over 100 miles, which is 15 minutes at 400 mph. At that distance the signal is far more limited by path loss than by line of sight issues. Consider that the cell phone transmit antenna is inside a metal tube and the only signal that escapes is via the windows. That loss factor would be quite a bit.
By saving that my Verizon cell phone works fine from cruising altitude, I was merely pointing out how wrong the 9-11 “truthers” are on this point and that it tells me all I need to know about their fanaticism.
I hold a FCC Commercial License and have the Radar Endorsement that was issued in 1969 apart from driving airplanes since then.
That's true when everything is working normally. The cellphones power down to a minimum power mode, and the plane acts like a cell tower. I think it does this indirectly, rather than transmitting on the cell frequencies, but that's irrelevant here.
However, if the presumed hijackers were smart enough to power down the transponders, they were probably smart enough to turn off that system. If they did, the cell phones would still most likely work on their own when within a reasonable distance from the cell towers. A couple of hours out into the ocean, they wouldn't work. But, you are probably right that either the passengers were dead or the phones were collected. With the info we have so far, I'd vote for death by depressurization.
You mean HCM -- for extended overwater operations everyone has to have continuous availability to dispatch, with two-way communications. I think they had ACARS, though it may have been disabled at some point.
For a couple of reasons we know that they did not power down that system.
1. It is the system that kept communicating with a satellite for hours, and the reason that they knew the plane was flying for hours.
2. The Sat was actually able to detect the cell phones. That is why loved ones could hear a long series of rings when calling.
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