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Engine Data Reveals That Flight 370 Flew On For Hours After It "Disappeared"
Advocatus Diaboli writes "Aviation investigators and national security officials believe the plane flew for a total of five hours based on data automatically downloaded and sent to the ground from the Boeing Co. 777's engines as part of a routine maintenance and monitoring program. As part of its maintenance agreements, Malaysia Airlines transmits its engine data live to Rolls-Royce for analysis. The system compiles data from inside the 777's two Trent 800 engines and transmits snapshots of performance, as well as the altitude and speed of the jet. Those snippets are compiled and transmitted in 30-minute increments, said one person familiar with the system."
Update: 03/14 11:41 GMT by S : The WSJ has since updated its report to say the data was from the plane's satellite-communication system. However, Malaysian authorities have denied both scenarios, saying neither Boeing nor Rolls-Royce received data past 1:07am (the flight initially disappeared off radar at 1:30am).
... by malaysian officials: http://www.theguardian.com/world/2014/mar/13/malaysian-officials-deny-flight-mh370-missing-plane-flew-hours
The phones weren't "ringing." the ring tone the relatives heard was supplied by Central Office Equipment to give the illusion that the phones were "ringing." That's what happens when someone picks up the phone and you say, "But it hadn't started ringing yet." Yes, it had. It's just that your simulation-ring hadn't reached you yet--two different tones. Think about it. There is only a single cable pair that hooks up a typical phone. How could you possibly "hear it ring"?
The cell network mimics the POTS network. It's just part of the "aural interface" phones have used for over a hundred years.
How about a moderation of -1 pedantic.
I would be a little surprised if the engine monitoring and satellite link circuitry would be on battery backup since it is unlikely engines and passengers would have much use for satellite link after the plane hits water. For the satellite link to work, the antenna would also need to remain above water since submersion adds horrible attenuation to radio signals. Additionally, cabin electronics aren't water-tight so submersion in ocean water would ruin them in fairly short order.
The on board engine monitoring module is only *ON* when the engine is turned on.
When the engine is off, the transmission module goes to sleeping mode, relies on it's tiny battery backup on keeping the date/time current.
Saying that the module keeps on transmitting AFTER the plane has broken up is not only inaccurate, it's downright irresponsible !
Actually air traffic control radars ARE radars, the transponder merely fills in the ID data (as a beacon as you said). Aircraft without transponders show up as unidentified targets with a heading, range, and speed. Transponders work are farther ranges because there is only a one way free space loss to the aircraft, when relying only on a radar "echo" the loss is both directions
The 777's two NiCad batteries have enough juice to power the essentials for about a maximum of 5 minutes in a complete electrical failure, which is simply unheard of on the 777. If you need the ship's batteries, you are far beyond being well and truly fucked. The airplane has 7 sources of electrical power. These include two engine driven 120KVA alternators, one 90KVA APU alternator, two 20KVA engine driven backup generators, an pnuematically driven generator, and a ram air turbine. There are also a permanent magnet alternator on each engine to power the FADECs. In addition, each flight control actuator has its own battery pack.
This is what we know so far, a good summary ...
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Not quite correct. The situation is quite a bit more complex than that.
ATC obtains information about aircraft in the area in a number of ways.
One is primary radar - which is in fact radar. It generally has a limited range - maybe 50 miles or so. Usually civilian equipment cannot detect altitude either, and of course it picks up noise from birds and weather and such.
The more useful source of data is secondary radar, which relies on transponders. The transponders generate a pulse when they are interrogated - the aircraft doesn't need to know its own location for this to work - the ground station works it out from the time to receive the reply. The transponder can encode a code to identify the aircraft, and it can also encode the altitude (or at least what the plane thinks its altitude is).
The more recent development is ADS-B via UAT and ES. These involve the aircraft broadcasting its position as determined by GPS. It can be sent out as part of the transponder reply, or it can be sent out without any need for secondary radar at all, potentially even being picked up by satellite.
So, radar is used to track aircraft, but with its limited range civilian radar would not detect an airliner out at sea unless it had a cooperative transponder. Even with a transponder range is only 100 miles or so. You can get much longer ranges with military radar, especially if it is airborne. However, stumbling on one of those would require luck, and a military aircraft probably wouldn't be on the lookout for rogue airliners.
AK Marc: I'm a licensed pilot, aircraft mechanic, and avionics technician, and have worked on FAA radar systems. What you say is completely untrue. Aviation surveillance radar worldwide is RADAR with capital letters. There is no WiFi involved, no AP, nothing like you describe. The system was designed in the 1960s and, except for some incremental enhancements, has been largely unchanged since then.
It consists of a ground based antenna system that transmits sweeping RF energy beams that bounce off metal objects such as aircraft (and occasionally flocks of birds) and reflect back to the antenna. The radar electronics complex processes digitized radar data streams from multiple antennas and generates a synthesized image, which appears on controller screens. Controllers can see this basic radar "blip" if they choose, although generally it's displayed as a faint background trace to keep the screen uncluttered.
The transponder system works by sending a coded signal that rides on the radar energy beam. When the beam paints an aircraft, the on-board transponder receiver decodes this as an "interrogation".
In its most basic form, called Mode C, the aircraft answers the interrogation with a data packet containing the a four-digit code assigned by a controller to the aircraft (which the pilot typically sets manually after receiving the "squawk" code verbally from the controller), and the aircraft pressure altitude. In the more recent Mode S, this packet contains additional data, such as the GPS location, airspeed, etc. Aircraft can overhear each others' Mode S replies and use that information to build an internal model of occupied airspace; this process is the foundation of the Terminal Collision Avoidance System (TCAS).
The transponder data gets painted on the controller's integrated radar display to make it easier to track targets. This is called "narrowband" mode because a this system can filter out a lot of clutter, leaving the controller with only verified targets to track. But if the narrowband system fails, which happens on occasion, controllers are all trained to revert to an old manual system using paper markers that they stick to their screens to track aircraft.
All commercial aircraft and many general aviation aircraft use Mode S today, and thus we collect quite a lot of data about flights in progress. In the Malaysian case, the aircraft was in radar coverage, receiving interrogations and responding, when they lost contact with it. Although the actual radar data hasn't been revealed, the sense of what has been shown so far is that the raw radar return, or echo, as well as the transponder Mode C, stopped simultaneously. It's possible that the controllers were not displaying non-transponder returns on their screens, so it may turn out that there was a raw signal for some time. That's the big question that, once answered, will indicate whether there was a deliberate action to turn off the transponder or a cataclysm turned it off. People can turn off transponders, but they cannot turn off raw radar signatures.