Egyptair MS804: significance of ACARS messages clarified

Airbus is not, at present, able to give specific advice to A320 operators based on information available from the Egyptair MS804 investigation, according to a report by Flightglobal senior journalist David Kaminski-Morrow.

Data transmitted by the aircraft’s ACARS messaging unit to the Egyptair operations centre is insufficient to point to a cause, he reports, explaining: “Airbus has already informed operators, via two accident information bulletins, that the available data is limited and that the analysis of the transmissions does not contain enough data to determine the accident sequence, Flightglobal has established.”

The Flightglobal report continues: “With the inquiry unable to conclude whether a technical flaw contributed to the crash, the airframer has been unable to provide any immediate advisory to operators.

“Although seven ACARS maintenance messages transmitted in the space of 3min – between 02:26 and 02:29 Egyptian time – hint at the possibility of smoke and heat in the forward fuselage, there is no confirmation that the time-stamp of the messages correlates with the order of the trigger event and no clear indication of the precise time interval between them.”

The unknown factor is the “trigger event” referred to. The ACARS messages (see earlier blog entries) and the circumstances of the crew’s loss of control over the aircraft do not provide specific evidence to indicate either sabotage or a fault as the trigger event.  But whichever it was, it appears to have generated fire that caused progressive electrical failures, and the crew’s loss of control over the aircraft ensued soon after that.

Floating wreckage and body parts recovered from the water where the aircraft crashed into the Mediterranean Sea north of Alexandria, Egypt, so far provide no clue as to whether sabotage or another cause brought the aircraft down. And the search coordinators have released no information about how widely the wreckage field is spread. This can be an indicator of whether the aircraft came down in one piece or had broken up in the sky, but after time the clues can be lost because the floating wreckage can be spread by sea currents and wind.

All this makes the recovery of the main wreckage and the flight data and cockpit voice recorders from the sea bed vital for the understanding of what caused the loss.


MS804: smoke in avionics bay, then flight control computers begin to fail

Egyptair operations centre plane screenshot


This is a screenshot of ACARS messages automatically datalinked from Egyptair flight MS804 to the airline’s operations headquarters shortly before the aircraft appeared – on radar – to go out of control.

News of the ACARS datalinked message first appeared in the Aviation Herald, a respected Salzburg, Austria-based journal that publishes on aviation safety issues. The French accident investigator BEA, which is helping Egypt with the inquiry, has confirmed the existence of the information. (ACARS = Aircraft Communications Addressing and Reporting System).

The printout/screenshot shows that all was more-or-less well in the aircraft until smoke was recorded in the forward lavatory just behind the flight deck.

A minute later smoke was recorded in the avionics bay, which is below the flightdeck floor, therefore close to the forward lavatory. The avionics bay contains all the electronic sensors and computers that provide the pilots with the information they need, and connections to the computers that direct the flight controls.

Two minutes after the smoke warning for the avionics bay the FCU 2 (second flight control unit) recorded a fault, and the SEC 3 (the N0 3 spoiler/elevator computer) also recorded a fault.

According to the Aviation Herald’s source, the ACARS feed then stopped.

Warnings about all these would have appeared on the pilots’ instrument panel.

There were other symptoms in the ACARS messages that popped up before the smoke was sensed by the system. These related to cockpit window de-icing and related window sensors, and were nothing to do with the aircraft controls but may have been yet another symptom of early fire damage to electrical systems.

The question now is whether the fire that caused the smoke was the result of an electrical fault – for example a short-circuit caused by damaged wiring – or whether some form of explosive or incendiary device was used – for example by a terrorist – to generate a fire or other damage.

The fire appears to have propagated fast. Flight control computers were failing within two minutes of the avionics bay smoke warning. If more of them failed subsequently the pilots would have limited means for controlling the aircraft, and with fire present, crew stress would have been extremely high.

That might explain the fact that there was no distress call. The pilots were trying to understand what the cause of the fire warnings was, where the source of the fire was located, whether they could do anything to stop it, and coping with a gradual degradation of their ability to control the aircraft.

These facts, providing they are not some kind of macabre coincidence, may have provided the basic reason why the aircraft went out of control and crashed.

But it is still not clear whether this situation was the result of terrorist action or an aircraft fault. Certainly no terrorist group has claimed responsibility.

And that answer is unlikely to be forthcoming soon. Even the recovery of the cockpit voice recorder and flight data recorded may not provide absolute proof of terrorist action – or lack of it – although the data will probably provide compelling circumstantial evidence.



Missing Egyptair flight MS804

It’s tempting to speculate that the loss of Egyptair MS804, an A320, was caused by sabotage because that’s what happened to the Metrojet flight out of Sharm el-Sheikh last year.

But, in the last decade, several aircraft have quietly gone missing during cruising flight without being brought down by explosives or in-flight break-up. The most obvious example was an Air France A330 that went missing in the south Atlantic in 2009, but there are others. And there is no information yet which would rule in or rule out either of those scenarios.

Greece’s Defence Minister Panos Kammenos has told a news conference that soon after entering Egyptian airspace, the A320 had turned “90 degrees left and 360 degrees to the right” before descending and disappearing off radar at 15,000ft. If that information is confirmed – and I have no reason to doubt it – the flight had clearly been destabilised, but the cause of the destabilisation is not known.

The aircraft’s last known position is over the Mediterranean south-east of Crete and south-west of Cyprus, but still more than 100nm off Egypt’s northern coast. Fairly soon some useful information is likely to become available because several military units – ships and aircraft – have been committed to a search of the area.

If, for example, there is a floating wreckage field and it is very widely dispersed, it will suggest an in-flight break-up.

But breakup can happen for reasons other than an explosion – although history and modern experience says that’s highly unlikely.

The aircraft and its “black box” recorders are almost certain to be found because, after other aircraft losses in the sea, recorders have been recovered in working condition from deeper waters than this.


The risk of “deliberates”

In the five fatal airline accidents in the first six months of this year 65 people died, while another 150 were killed in the Germanwings aircraft, which was not an accident.

This bears comparison with the first six months of 2014, where there were five fatal accidents causing 28 deaths, plus the enigmatic disappearance of MH370 in which 239 people were lost. Although it cannot be proven, most industry experts believe MH370’s disappearance was a the result of a deliberate act by someone on board.

In terms of fatal accident numbers for the same period each year in the last decade, 2015’s accident figures equal the best. But the “deliberates” are beginning to pose new questions about airline safety, because there was one in 2013 as well – that’s three “deliberates” in three years.

The 2013 “deliberate” involved Mozambique airline LAM which lost an Embraer 190 twinjet and all 33 people on board under the same circumstances as the loss of Germanwings flight 4U9525. That is, one pilot left the cockpit, the other locked him out and deliberately flew the aircraft to impact.

The question is: do three such “deliberates” in three years constitute a trend or a coincidence?

Statistically there’s not a strong case for calling it a trend, but neither can it be ignored.

Look at similar cases before the LAM loss: Egyptair 767 in 1999, Silk Air 737 in 1997, and a Royal Air Maroc ATR42 in 1994. So, in that period 1994-1999 there was one loss every two years. Then there was a long gap – 13 years – with no deliberates. Then between 2013 and 2015 there were three: LAM, MH370 and Germanwings.

Hijacks are also “deliberates”, but since the adoption of the post-9/11 fortress cockpit, plus anti-hijack cabin crew drills, hijacks have been eliminated.

Sabotage is a deliberate act, but security is now so extensive that even those who have smuggled small quantities of explosives on board have failed to detonate them effectively.

So the only “deliberates” against which the industry has no effective defence are those that can be carried out by people in the cockpit or with authorised access to it.

The nearest the industry has come to a defence against this risk is never to leave a pilot alone in the cockpit, so if one of them leaves it, a member of the cabin crew has to replace him or her. This is a useful psychological technique for making it less likely that a pilot in a suicidal frame of mind would initiate a plan when there is a witness to it. Less likely yes, but not impossible.

What is needed is some careful study, probably across other industries also, of people – and their life circumstances – who use their workplace either to end their own life, or for a revenge motive resulting from resentment so embedded that their own survival becomes irrelevant.

If this three-in-a-row set of deliberates is a trend, is it generated by societal changes, including working cultures, or is it just a matter of chance associated with the power and opportunity that control of an aeroplane confers?

Such a study would be complex and may not be conclusive, but that is no excuse for failing to carry it out.