Russia Confirms Jet Broke Up in Mid-Air; Did 2001 Accident Doom It?

11.01.15

The airplane fell apart before crashing, evidently near the tail. That could mean a ‘tail strike’ from 14 years ago was never truly fixed.

Editor's Note: This story has been updated throughout.

The head of Russia’s aviation accident investigation body has confirmed that the Russian Airbus A321 that crashed in the Sinai on Saturday broke up in mid-air. Victor Sorochenko said that the wreckage was spread over an area of eight square miles – not concentrated in one debris field.

This would be consistent with a severe and very sudden structural failure that resulted in the airplane literally falling out of the sky from its cruise altitude of 31,000 feet. (An Egyptian statement that the pilot had reported a technical problem and asked for a diversion to the nearest airport was later withdrawn.) 

The Airbus A321 was 18 years old, and had made 21,000 flights, a relatively low number when compared with the much higher daily frequency of flights made on budget airlines. With a modern airplane like this and regular maintenance its age is not in itself a cause for concern. 

What does, however, jump out from this particular airplane’s record is anaccident that it suffered on November 16, 2001, while landing at Cairo (while owned and operated by Middle East Airlines). As it touched down the nose was pointing at too high an angle and the tail hit the tarmac—heavily enough to cause substantial damage.

Tail strikes like this are not uncommon. The airplane was repaired and would have been rigorously inspected then and during subsequent maintenance checks. (Although the airplane was owned by a Russian company, Kogalymavia, operating as Metrojet, it was registered in Ireland and the Irish authorities were responsible for its certification checks.) Nonetheless investigators who will soon have access to the Airbus’s flight data recorder will take a hard look at what is called the rear pressure bulkhead, a critical seal in the cabin’s pressurization system. 

A Russian television reporter said that the remains of the tail of the Airbus were found three miles from the rest of the wreckage. Images of the tail section show a clear break near the site of the rear pressure bulkhead.

Debris from the cabin section of the crashed Russian jet lies strewn across the sand at the site of the crash, Sinai, Egypt, 31 October 2015. (EPA)

In the event of a failure of this bulkhead, the airplane would have suffered a sudden and potentially explosive decompression; at its final recorded altitude of 31,000 feet the difference between the pressure inside the cabin and the air outside would have been at the point where such a catastrophic failure would be most likely to occur. The wreckage shows no signs of a fire or an engine-related explosion.

Debris from the tail section of the crashed Russian jet lies on the sand at the site of the crash, Sinai, Egypt, 31 October 2015. (EPA)

The Egyptian Prime Minister, Sherif Ismail (2 - R), examines the wreckage at the site of the Russian plane crash, Sinai, Egypt, 31 October 2015. (EPA)

The new reports from the crash site make it clear that investigators are now able to rule out that the airplane was destroyed by a missile fired by jihadists who have been active in that part of the Sinai. Despite this, some airlines, including Lufthansa, Air France, and Emirates have announced that they will no longer fly over the Sinai, even though this disaster is almost certainly not a terrorist act.

Investigators Searching for Clues in the Plane Crash Site in Sinai

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I checked the traffic over the Sinai only an hour after the accident was reported. Two corridors were being used, one over the northern Sinai with flights at cruise height of 36,000 feet or more, and a far busier one over southern Sinai with flights at different and often far lower altitudes—some on approach to or departing from Cairo, to the west, some headed for Sharm-el-Sheik, the resort from which the Russian jet departed for St. Petersburg.

Since Malaysian Flight MH17 was brought down by a missile strike over Ukraine, the main flight corridors between Europe, the Middle East, and Asia have beenchanged to avoid war zones. 

The result has been like a highway diversion—much more traffic has been pumped into an alternative route that takes jets over Turkey, Cyprus, and the eastern Mediterranean to a waypoint at Alexandria, Egypt, and then eastward over Cairo, the Sinai, and Saudi Arabia to the southern Persian Gulf. There is a major international hub in the Gulf at Dubai, which means that these airlanes are now crowded with long-haul flights routed through Dubai.

Until now the Sinai has not been treated as a war zone, but clearly some airlines are now going to give it a miss. Those that have regular tourist-popular routes into Sharm el-Sheik, like British Airways and Ryanair, have said that they will continue to fly into the southern Sinai. And there is no evidence from the tragedy of the Russian Airbus to suggest that they are wrong.