Sinai

Sinai crash update

David Learmount , , ,

The wreckage field for the Metrojet A321 crash in Sinai is wider than originally reported – about 5km across at present, and in time maybe even more wreckage will be found.

If this report is accurate, it indicates an in-flight break-up of the aircraft, but the cause cannot be determined with certainty at this point.

Causes of in-flight break-up could be related to a missile strike or a bomb on board, but there is no proper evidence for those right now. There has been an “Islamic State”  claim of responsibility, but it has not been backed up with any evidence either.

Speculation in the media has begun about a possible fuselage failure caused by damage to the fuselage that was – allegedly – not properly repaired by the airline, causing an explosive decompression and in-flight structural failure. The kind of damage suggested in this speculation is a tailstrike on the runway during landing or take-off. But this is guesswork. It is not based on evidence.

Modern engineering makes aircraft extremely strong, so total in-flight break-up without extreme stress being applied to the structure is impossible. Thousands of Airbus aircraft in this series have been flying since 1988 and no such event has occurred.

Sinai A320 crash

David Learmount , , , , , ,

The Russian Metrojet aircraft lost in north-central Sinai today was a leased Airbus A321 that entered service 18 years ago. Its reported passenger load was 224 people, which means its cabin was full or nearly full.

It had left the southern Sinai coastal resort town of Sharm el-Sheikh heading north for its destination, St Petersburg in Russia. Its route took it across Sinai – where the weather was good – and it would have continued northward over Cyprus and Turkey.

According to commercial flight tracking service Flightradar24 the aircraft was seen to suffer a disturbance which caused rapid variations in its speed and height, reducing the speed to 6okt at one point, which would put it into a deep stall condition unless the crew acted rapidly to recover speed again. Then the aircraft developed a high rate of descent – about 5,000ft per minute, and the position, height and speed information from the aircraft’s transponder was lost.

Flightradar24’s information about the Germanwings aircraft lost in the French Alps earlier this year proved to be highly accurate, and ahead of official information from the investigators it became evident that the A320 had  begun what looked like a deliberate descent to impact, and so it subsequently proved.

In this case the information is more complex because of the apparent speed and height variations that preceded the fatal descent.

The Egyptian authorities have been quick to rule out terrorist action in the form of sabotage or a missile strike, but it is too soon to rule anything out. Sharm el-Sheikh is an important Egyptian tourist resort, and any suggestion of security breaches affecting travellers there would be harmful to trade.

The aircraft was cruising at 31,000ft, at which it would be safe from the kind of man-portable missiles that terrorists in the area could obtain fairly easily, but the aircraft was 2,000ft lower than the Malaysia Airlines Boeing 777 that was shot down over eastern Ukraine last year by a more powerful ground-launched missile.

Early information suggests the aircraft came down in one piece and broke up on impact, making the missile strike theory less likely. On-board sabotage, however, does not have to break an aircraft up in order to damage its controllability.

So at this point it is certain that the aircraft suffered a serious upset during the cruise, but there is no indication why that occurred.