A brief update on the Sinai air disaster. A statement by the head of Russia's Air Transport Agency that the Airbus which crashed on Saturday "disintegrated in the air at a high altitude" has renewed media speculation about a jihadist attack.

An editorial in today's Daily Mirror, for example, says talk about a technical cause "would seem like a convenient excuse for Egypt and Russia’s autocratic rulers". 

While it's true that statements from Egyptian and Russian officials are not necessarily trustworthy, the fact of the matter is that either a bomb or a botched repair from a previous accident could have caused the aircraft to break up in flight and, on present evidence, the latter seems more likely.

The most plausible explanation so far, as I discussed in a blog post yesterday, is that the tail broke off as the plane approached cruising altitude, sending it out of control. 

We know that the aircraft suffered "substantial" damage when its tail struck the runway at Cairo airport in 2001 – damage which took three months to repair. We also know that at least two airliners have crashed as a result of defective repairs following tailstrikes years earlier (in one case, 22 years; in the other case, 
seven years). In both those crashes, the repair had left the aircraft less resistant to metal fatigue in the tail section than it should have been and repeated cycles of pressurisation and depressurisation in flight eventually led to a fracture.

At the time of its tailstrike 14 years ago the Airbus that crashed in Sinai was not in Russian hands. It had a different registration mark (F-OHMP) and was operated by Middle East Airlines of Lebanon. On 16 November 2001 it came in to land at Cairo airport on a scheduled flight from Beirut. A report on the website of Aviation Safety Network describes what happened:

"The flight ... was cleared for an ILS [Instrument Landing System] approach to runway 05R. Reportedly, as the aircraft was descending through about 200 feet, it 'ballooned up' and the pilot had to apply nose-down pitch to regain the glide path. Descending through 100 feet the pilot again applied nose-up pitch to correct the glide path. The aircraft then suffered a tail strike."

What we know from photographs of the Sinai crash site is that the tail separated from main body of the aircraft before hitting the ground. A mangled section of the tail, with its vertical stabiliser, landed a considerable distance away (one minute into this video) and, unlike much of the wreckage, it shows no signs of smoke or fire damage. An object which may be the tail cone appears in a different position again (1 min10 sec into the video). As yet, there appear to be no images showing the location of the tail's horizontal stabilisers.

Of course, this circumstantial evidence doesn't rule out the possibility of a bomb on board but it strongly suggests the crash had a non-terrorist cause. 
  
   
Posted by Brian Whitaker
Monday, 2 November 2015