Engine Data Reveals That Flight 370 Flew On For Hours After It "Disappeared" 382
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).
Already denied (Score:5, Informative)
... by malaysian officials: http://www.theguardian.com/world/2014/mar/13/malaysian-officials-deny-flight-mh370-missing-plane-flew-hours
Re:Already denied (Score:3, Informative)
And the story has since been updated. There were no new ACARS messages with engine data, so that is consistent with the malaysian officials.
However, what the article now says it that the airplanes satellite link was trying to connect to the satellite, it just wasn't sending any data.
Correction: Signal NOT from the engine monitors (Score:5, Informative)
Re:Combined with the ringing phones ? (Score:5, Informative)
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.
Re:It wasn't the engines sending data (Score:5, Informative)
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.
Why is everybody so hung up on terrorist? (Score:5, Informative)
My money is on something like what heppend to flght ZU 522 http://en.wikipedia.org/wiki/H... [wikipedia.org]
Re:What about radar? (Score:1, Informative)
Monitoring module only functions when engine is on (Score:5, Informative)
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 !
Re:Already denied (Score:4, Informative)
The Malaysian Airlines 777 in question didn't have satellite ACARS capability, only VHF (and maybe HF too) radios carrying ACARS data. I'm not even sure it had any SATCOM equipment fitted at all. There was a recent airworthiness directive for 777-series aircraft about hull skin problems where SATCOM antennas are mounted on the top of the fuselage but it didn't apply to the Malaysian Airlines 777s since apparently they didn't have those antennas fitted.
If the HF and VHF radios on board were shut down for any reason then there would be no more ACARS data received by ground stations.
Re: Combined with the ringing phones ? (Score:5, Informative)
One bit of info that *might* be of interest... cell phone towers beacon to announce their presence to phones, but individual phones actually *poll* towers every few seconds. The reply from the tower lets them know when there's an incoming call, deliver SMS & voicemail notifications, etc. In theory, at least, if the mobile phone of any passenger came within range of a cell tower it was allowed to poll, there's probably a log of it somewhere.
That said, if the jet was at cruising altitude, the likelihood of a phone on board *doing* that is almost nil, because tower antennas are generally aimed downwards... partly, to minimize interference from airborne mobile phones that could otherwise splatter noise over a 40-100 mile radius (the line of sight when your transmitter is 5+ miles up in the air).
Re: Combined with the ringing phones ? (Score:5, Informative)
On original POTS circuits the ring tone was actually the 25Hz signal sent to the phone with the phone's bell coils supplying some of the ringback harmonics along with a ring generator. With a good ear you could estimate how many phone sets were ringing. The audio path was already set-up while the phone rang. If the called party was too near an AM broadcast transmitter you might even hers some of the program between rings. The off-hook condition on the called party just disconnected the ring generator at the CO and started any billing equipment.
Of course this all ended with the last of the Stroger and crossbar offices.
Re:What about radar? (Score:5, Informative)
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
Re:It wasn't the engines sending data (Score:5, Informative)
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.
What we know so far ... (Score:5, Informative)
This is what we know so far [bbc.co.uk], a good summary ...
Re:Already denied (Score:5, Informative)
Actually, I'd like to know where you got the information on the exact equipment on board this plane?
What is being denied is that Malaysian Airlines subscribed to this monitoring program, not that it was not so equipped (*).
The latest reports [go.com] is that the radios are there and ping the satellites even when they are not going to transmit data.
U.S. officials said earlier that they have an "indication" the missing Malaysia Airlines jetliner may have crashed in the Indian Ocean and is moving the USS Kidd to the area to begin searching.
It's not clear what the indication was, but senior administration officials told ABC News the missing Malaysian flight continued to "ping" a satellite on an hourly basis after it lost contact with radar. The Boeing 777 jetliners are equipped with what is called the Airplane Health Management system in which they ping a satellite every hour. The number of pings would indicate how long the plane stayed aloft.
(Sort of like a cell phone with an expired sim still talks to the towers).
This is coming from the white house.
You will remember YEARS AGO when the Russians shot down a commercial airliner [wikipedia.org], that the NSA pulled recorded conversations between the Russian pilots and their base, WEEKS after the incident, embarrassing the Russians.
The US probably has more data on this indecent than they are willing to reveal at this time.
*This makes sense, because the airlines can turn the feature on by simple writing a check.
Boeing builds it into the fleet on the hopes of selling the service.
Re:What about radar? (Score:5, Informative)
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.
Re:What about radar? (Score:3, Informative)
There are a lot of reasons. Air traffic control is about 90% reliant on transponders. Without a transponder, an aircraft is just a "primary target" or blip on the scope. In most cases there is no computerized synthetic track associated with a primary target. Remember, air traffic control radars are designed to track cooperative targets, not like a military radar designed to track non-transponding, uncooperative targets. Yea, if they had an AEGIS it would be able to track the airplane exactly, but they didnt.
There is virtually no non-transponding traffic at high altitude. ATC controllers can turn the gain on the skin paint (primary target) up/down to clean up the scope, and usually its down. Sometimes the RADAR may not even be operating (other than the transponder). Actual radar coverage to allow skin paint is not that great. You might be surprised at the places in the US that do not have 100% coverage. If you fly across the gulf of mexico from Houston to Key West, you will be out of radar coverage for some of the trip. If you are out in the big open west USA (Airzona, Nevada, eastern CA), and drop below high altitude you will go out of radar coverage rapidly.
I find it interesting that the last communications with this aircraft was when handing off from one control facility to another. If I wanted to "disappear" an airliner, that is exactly the right time to do it. You check out with one controller, then just never check in with the next. Normally an automated "strip" would go across with the handoff, but If the controllers are in different countries, you can bet on significant delay in the land-line communications between the two to figure out what happened.
I'm a pilot
Re:What about radar? (Score:5, Informative)
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.
Re:What about radar? (Score:4, Informative)
There is no parallel with WiFi. WiFi broadcasts are just data packets; radar interrogations are directional energy beams that locate aircraft in distance and azimuth. WiFi broadcasts are no different from the packets the client sends back to the AP: the framing, timing, and encoding is identical. But radar interrogations are tri-pulse trains on a common global frequency, with unique timing to identify the type of interrogation. Transponder replies are at a different common global frequency transmitted in as TDM-encoded data frames. Replies are omnidirectional and only pass data generated by cockpit instrumentation back to the radar station.
Thus transponder data is only used by controllers for identification and altitude, and some ancillary data. Mode S GPS content in transponder replies is used by other aircraft for TCAS, not by controllers for position information. If the aircraft is outside reflection range, it won't transpond. By definition if the transponder replies to an interrogation, it was because the aircraft was being painted by a radar's "skin" beam, which at microwave frequencies means there is line of sight between the aircraft and ground antenna. The radar echo is guaranteed to make it back to the station because of this line of sight. On an aircraft the size of a 777, very little energy needs to be reflected to generate position data, and I've never seen a situation where transponders don't have a corresponding primary radar blip.
All these differences between reality and your analogy lead to radically incorrect conclusions about system capabilities and behavior. I can say the earth is like and egg, because they're both round, but that doesn't make it a good analogy.
Possibly diverted to the Nicobar / Andaman islands (Score:4, Informative)
Re: Combined with the ringing phones ? (Score:4, Informative)
Not completely correct, but on the right lines...
GSM and 3G phones listen to the cell tower's Pilot carrier, which contains a whole bunch of data (which network, neighbouring cells etc). thenetwork will broadcast a request for a particular phone to contact it when there is incoming traffic (eg call or SMS) for that phone.
To reduce the volume of traffic, it only broadcasts this request over a small(ish) no of cells, called a Location Area (LA). And how does it know which LA to poll - because part of the broadcast data on the pilot channel is the LA identifier - so when a phone switches from listening on one cell to listening on another (which it doesn't inform the network about unless it is mid call) it checks the LA number, and then updates the network with it's new LA when the LA identification changes.
So if anyone on the plane left their mobile switched on (and with a couple of hundred people on the plane this is a racing certainty), then by checking the operater records for all the phones, LA updates will be there (and yes, operators are required to keep this meta-data for the intelligence services).
In consequence, I would be extremely surprised if the NSA / GCHQ / KGB and Chinese Military Intelligence did not already have a good indication off where the plane was (or was not).
Re:It wasn't the engines sending data (Score:5, Informative)
OP has it right, but we can add more information. I've been following the discussion over at www.airliners.net [airliners.net] where some people know more about this plane's electronics.
First some back story. The SATCOM system is sort of like your cable modem, or more accurately a cell data stick for a laptop. It's a sort of modem that knows how to connect to the satellites. Like a unprovisioned cell phone it still reaches out and says "can I have service", and then gets no answer. ACARS is an application that runs on another computer in the plane. It's sort of like a "twitter feed" for a plane. Short messages can be placed on it and routed off to other places. Boeing offers a service where the plane reports its health back to boeing using this application. Rolls Royce offers a service where the engines report back to them using this service. Pilots can even send short text messages over the service back to their HQ. The GPS system can send a message with its position. ACARS knows how to transmit over HF, VHF, and SATCOM. It also goes through a cleaning house (think twitter again) who routes the individual messages to the right party.
Mayalsia Airlines apparently bought the "limited" package of monitoring. As such ACARS was programmed to send no information to Boeing, and only limited information to Rolls Royce. Compare with the Air France crash in the Atlantic where they subscribed to the "full" suite of monitoring and 29 messages were generated. Further, Mayalsia apparently didn't pay for SATCOM airtime, instead letting it report over HF and VHF. If it was far enough out over water these methods would not be within reach of the radios.
However, the plane still had a SATCOM system on it (comes standard), and it was still like an unprovisioned cell phone saying "can I have service", apparently once per hour. Further the satellites in orbit have directional antennas that cover a particular section of the ground. It appears in this case ACARS was disabled (either intentionally, a small switch in the cockpit) or via failure (fire, or whatever).
The key detail is that while ACARS and many other functions can be turned off from the cockpit, the only circuit breaker for the SATCOM systems are NOT in the cockpit according to experts. It would require going to the electronics room on the plane which is not easy to reach in flight, and more importantly would not be possible to reach if a individual had taken over the plane.
So the stories line up. Boeing received no messages as the plane was not programmed to send them any. Rolls Royce received two during the normal part of flight, and then nothing as the system was turned off or disabled. However that SATCOM modem apparently continued, once per hour, to look for service. I guess the US authorities were able to talk to the satellite provider and get logs of it making those requests, and perhaps even narrowing it down to a specific antenna on the satellite.
On power; the experts say the plane has ~30 minutes of battery in the case of total electrical failure. In flight it also has a ram air turbine (think mini-windmill) that can generate enough power. If it did a "miracle on the hudson" style landing in water and it somehow stayed afloat (being under water even 1' makes the sat signal too week) batteries would only last ~30 minutes.
One of the most bizarre incidents ever recorded. The outcome of this is going to be very interesting.
Re:What about radar? (Score:4, Informative)
But BOTH raw radar data and transponder replies are recorded at the controller's station (actually by he computer, of course). This way aviation authorities can reconstruct exactly what the controllers saw on their screen. I worked on software for the original version of this system, which was written in the Jovial programming language and IBM basic assembly language (BAL). The software and computers have changed, but amazingly the radar system itself has evolved very little, other than wth the addition of more stations and better data collection networks.
The movie "Pushing Tin" (Angelina Jolie, John Cusack, Billy Bob Thornton) is actually a pretty accurate depiction of how it all works. Not a lot has changed since that movie was made. The movie's title comes from slang for what controllers still do today when they lose their computer capability and have to deal with just primary radar returns. They push little paper markers around on the screen and keep track of flight information with paper data strips, and that serves as the emergency backup mechanism in the event of a computer failure.
Re:What about radar? (Score:4, Informative)