Original URL: http://www.theregister.co.uk/2014/03/18/mh370_airliner_mystery_the_iel_regi_pubdinnerparty_guide/

MH370 airliner MYSTERY: The El Reg Pub/Dinner-party Guide

Some tech angles for your consideration

By Lewis Page

Posted in Security, 18th March 2014 11:39 GMT

Analysis So, the mysterious case of the missing flight MH370. We've mainly stayed out of this - apart from noting that no, the jet wasn't hackjacked using a mobile phone. But naturally we've been poking around a bit to see what we could find out, and it's not completely nothing.

Here's what we bring to the party. Some of us know a bit about aviation, occasionally to the extent of having held pilot's licences. Some of us know a bit about the theory of navigation. Some of us know a bit about satellites and wireless data generally. And we happen to know an experienced airline pilot who has flown Boeing 777s. So we've been able to drill through a lot of misleading reports about "satellite tracking" and extended flight below 5,000 feet and that sort of thing.

So here's the timeline as we understand it, with what insight we can add:

0041 local time 8 Mar (1641 GMT 7 March)

Flight MH370 takes off from Kuala Lumpur headed for Beijing. Scheduled landing time was 0630, approximately 5 hours 50 minutes later.

Our man in the cockpit tells us that it would be normal to have enough fuel to arrive at Beijing, then to divert to another airport (+1 hour) plus a further reserve (+30 minutes more, give or take). Thus the plane would normally have taken off carrying fuel for perhaps 7 hours 30 minutes in the air. If the captain wanted, "he could easily take another hour's fuel without the copilot becoming too suspicious, especially in such a vertical crew culture as the far eastern carriers have". (Normally a captain tries not to overload a plane with fuel as air-freighting fuel from airport to airport costs fuel - and thus money - in itself.)

Our man adds: "IF they were both in on some type of plan they could have filled it up to whatever level of fuel they wanted, all the way to maximum tanks fuel which could give them 13-14 hours endurance at the limit".

Malaysia Airlines Boeing 777 9M-MRO

Boeing 777-2H6ER 9M-MRO, the aircraft used on flight MH370. Credit: Rodger McCutcheon, Auckland Photo News

We'd note, though, that if the plane had taken on an unusually large amount of extra fuel the fact would probably have leaked to the media by now, and the Malaysian government would be speaking of different search areas than it is doing. Some Far Eastern reports suggest a full 8 hours' worth or more of fuel was loaded (as opposed to 7 as most of the media are suggesting) and this would be cautious but normal conduct by the captain.

0107 local time 8 Mar (1707 GMT 7 March)

As MH370 crosses the Malaysian coast headed out over the South China Sea, the final Aircraft Condition Monitoring System (ACMS) report is transmitted from the plane via the Aircraft Communications Addressing and Reporting System (ACARS) data link. This is an automated report containing a variety of information from systems aboard the plane, relayed to various destinations on the ground via VHF radio or (when out of range, as when over the sea) by satellite communications.

The data reporting - and indeed the aircraft's satellite communications for all purposes - was disabled via processes that would have required navigating through some menus on the flight deck and selecting options on a keypad. Most 777 pilots would be able to do this, much though it isn't something they would ever normally do.

However the ACARS satellite communications equipment was not, in fact, completely disabled. The plane's satellite transmitter continued to automatically send short radio "blips" each hour. These contained no data as such: the purpose of the transmissions was to inform the satellite up above that there was an active transmitter there which might send a message at some point. The satellite would thus know to keep one of its receiving assemblies aligned at a suitable angle.

It would be possible to turn off this transmission also, but that would mean getting into an electronics bay below the cockpit. Our pilot source didn't even know that such transmissions took place until all this happened, though he thought that if he had known he could get into the bay via a locked floor hatch (actually in the forward galley on the 777s he had flown) and cut power altogether to the satcomms equipment. He adds that if someone other than the pilots gained access to the electronics bay and interfered with comms kit, alarms and notifications would have appeared on the flight deck, so it's all but certain that the pilots were involved in the process - whether under coercion or not.

0119 local 8 Mar (1719 GMT 7 March)

As the aircraft is handing over from Malaysian to Vietnamese traffic control, the final voice transmission is received in Malaysia - apparently sent by the co-pilot - saying that all is well and "good night". The flight never contacts Vietnamese air controllers, and at the same time the aircraft's secondary-radar transponder is switched off.

Background: Most aircraft are fitted with secondary-radar transponders which, when they detect the emissions from an air-traffic radar on the ground, send a response signal which includes a "squawk" code. The controller sees on his or her screen not only a dot showing the plane's location but also the identifying code, greatly simplifying his or her task. Without benefit of transponders, civilian air traffic radars are essentially useless, especially at long ranges. MH370 thus disappeared from civilian ATC screens at this point.

However a military air defence radar is designed to work without benefit of transponders, detecting an aircraft purely by its own transmitted radio energy reflected back off the plane's body (the so-called "skin paint", which stealth-fighter designers strive so hard to eliminate). Flight MH370 was still at this point being tracked by Malaysian air defence radar, and later reconstruction of military radar logs shows that the airliner - having turned off its transponder - then swung round away from China to head due west. The Malaysian air force tracked it as it flew right across the Malaysian peninsula, partly over their territory and partly over Thailand. (The fact that a large unidentified aircraft could do this without the military radar operators apparently caring enough to notify anyone is now causing a certain amount of trouble for Malaysian air-defence commanders.)

The military radars apparently detected various changes in height, but it should be noted that the ability of a long-range search radar to tell what height contacts are at is usually pretty poor. Other strange height data have supposedly been established from early ACMS engine data reports, but these aren't being given a lot of credence either.

0215 local Mar 8 (1815 GMT 7 March – Plane now airborne 1 hour 34 minutes)

Malaysian military radar loses contact with flight MH370 over the Andaman Sea, headed outbound in the direction of the Indian Ocean.

The extent and effectiveness of a country's air-defence radar coverage is normally a military secret, so other countries in the region are naturally reticent about whether they did (or could) detect the rogue airliner at any stage. So the last publicly known position of MH370 is when the Malaysian air force lost it.

However, almost certainly unknown to whoever was directing the airliner's course, its satcomms equipment was still sending its automated blips each hour to a geostationary communications satellite orbiting high above the Indian Ocean. Each blip was logged, and subsequently experts were able to use the records to generate an estimate of what range the aircraft was at from the satellite at that point. (In theory this would mean the satcomms transmitter could be anywhere on large sections of a sphere around the spacecraft, but assuming that the plane is within the Earth's atmosphere allows a circle to be drawn on the map.)

0811 local 8 Mar (0011 GMT – Now 7 hours 30 minutes after takeoff: if the plane had a normal fuel load it would be running out around this time)

The final blip is received from MH370's satcomms equipment, indicating that the plane's systems were powered down within one hour after that point. This could be because it crashed, or (as our 777 driver points out) because the plane then landed and was shut down completely to "batteries off" by the pilots. It might, indeed, already have been on the ground but not yet shut down when the last satcomms blip (or even maybe the last couple of blips, say) were sent.

This final blip was then used to generate the two arcs along which the search for the missing plane is now focused. One is far out in the Indian Ocean west of Australia (though this arc does include the possibility that the plane circled round to land/crash in Indonesia).

A handout from the Malaysian government showing the possible last locations of flight MH370 based on radar ... see below for it in context against a map of the world

The northern arc as specified by the Malaysian authorities (with help from British satcomms firm Inmarsat) runs from the Central Asian 'Stans down across the wilderness of Western China (including Tibet) and then along the Himalayas and down to the borderlands where Burma, Laos, Thailand and Vietnam come together with China - the so-called "Golden Triangle" where around half the world's heroin comes from. Much of the area, though nominally under the control of the respective national governments, is actually a conflict zone dominated by warlords, rebels, narco-trafficking gangs or combinations of all three.

One could say the same things of the 'Stans (which make up much of the "Golden Crescent" where most of the rest of the world's heroin comes from) but unlike the Triangle the area around Afghanistan is under heavy US military aerial radar surveillance: most probably including airborne radar watch by AWACS planes and/or E-2 Hawkeyes operating from US carriers offshore. If MH370 had made it that far, it would probably have found itself being investigated by US fighters.

So the Malaysian authorities' arcs seem reasonable enough, given that they seem confident the plane did not return to the region it departed from (perhaps having received some co-operation on military radar logs from other nations out of the public eye).

And that's most of what we know. We can add that the arcs appear as lines on a large-scale map, but in reality a line-of-position generated like this will not be exact. Further, the plane could still have carried on flying for up to an hour after the final blip was sent - so it could be hundreds of miles off the arc in any direction. The searchers have two immensely long, wide strips to cover - not lines.

Our 777 pilot does have a couple of things to add. Some reports, for instance, purporting to be based on military radar data, suggested that the missing jet might have descended to a low altitude to get out of radar coverage (going low can naturally drop a plane below the horizon a radar sees. Radar transmissions generally travel in straight lines and can't normally detect anything below the horizon as seen from the radar). However:

Down low it would burn fuel at the same rate (ish) so could stay airborne for a similar period of time but could only fly at about 220kts (faster would incur a great fuel penalty) giving a range from last known position in the order of 1200NM. That's why we fly them at [37,000 feet]!

In other words the jet could not have made it onto the arcs where the last satellite blip came from, had it been at low level for any great length of time.

As for a possible explanation for the affair, our airline man is as baffled as anyone else. However he had an intriguing note to add:

We often carry lots of cash ... not every country has the capacity to produce its own banknotes for example. And gold too on occasion. The captain is always notified of such special loads (along with any dangerous goods, munitions of war, firearms, etc) on what is called a NOTOC - a bit of paper detailing such a load and where it is in the holds.

Again, it seems likely that if any such load had been aboard the plane, the fact would have been revealed by now. On the other hand, transfers (or failed transfers, or disappearances) of significant amounts of gold or currency reserves can have serious effects on national markets and economies: there could be good reasons for a government or governments to keep such a loss out of the media for as long as possible. And the fact of such a cargo being on a particular flight is one of the relatively few things that the aviation industry actually tries properly hard to keep secret in the first place.

So it's an outside possibility, decreasing as time goes by with no such news.

Other than that, insight is hard to come by. But one can say that the whole operation involved a lot of expertise and effort: someone seems likely to have had a very good reason to carry it out.

It's possible to say that along the Chinese arc among the Tibetan rebels and the warlords of the Triangle there are a lot of situations going on which might drive people to do bad or desperate things. That's not so much the case with the empty Indian Ocean west of the Australian continental shelf. So we'd hazard a guess that if and when MH370 is found, it'll be on the northern arc rather than the southern one.

But the truth is, we don't know. And there remain plenty of scenarios in which neither the missing Boeing nor any of the people on board will ever be found. ®