The El Al Boeing 777 landing gear failure – first indications

Preliminary findings from the investigation into the emergency landing of an El Al Boeing 777 last month raise the possibility that the failure of one of the main landing gear was caused by the overhaul of the unit in an MRO centre in Singapore.

Yitzhak Raz, chief accident investigator at the Israeli ministry of transport, said that the cause of the failure is probably work that was performed on the landing gear during the overhaul.

Raz said that the exact cause of the failure has not been detected yet, and therefore the investigation continues.

He added that in spite of the fact that all signs point to a focused problem with the El Al 777 landing gear, other units will be checked around the world.

The investigation is now focused in the MRO centre in Singapore, and this in co-operation with experts from the US’s NTSB and FAA.

Immediately after the emergency landing on May 23, it became clear that a “severe structural failure” caused it.

The El Al 777 took off on a flight for Newark Liberty airport with 279 passengers on board when there was an indication that the left main landing gear does not retract.

The captain decided to go back to Tel Aviv and landed after large numbers of fire engines and ambulances arrived to the airport.

Israeli air force F-16s escorted the 777 and their pilots tried to see if there were signs of damage to the stuck landing gear. The 777 landed safely.

 

El Al is very anxious to get the final findings of the investigation. The preliminary ones were a sort of relief to the Israeli airline that in 1992 lost a 747 freighter because a problem with a minor part that should not have failed in the specific condition of the fatal flight.

On October 4, 1992, an El Al 747 freighter crashed in Amsterdam, killing all four people on board and more than 50 people on the ground. The cause of the crash was the No 3 and No 4 engines that separated from the wing, causing loss of control.

The reason for the No 3 engine separation was a breakage of the fuse pin. The pin was designed to break when an engine seizes in flight, producing strong torque.

Both of the engines separated from the right wing, causing the Boeing 747-200 freighter to crash as it tried to go back to the airport.

This was not the first Boeing 747 to crash in this way. In December 1991, a China Airlines Boeing 747-200F freighter crashed shortly after take-off.

A possible reason for the shearing away of the two right engines is that corrosion and fatigue weakened the fuse pins that hold the strut to the wings.

 

In both the El Al crash and the China Airlines crash, the No 3 and No 4 engines on the right side of the plane ripped away from the fuselage.

It is believed that in the El Al crash the inboard fuse pin failed due to corrosion cracking and fatigue that caused the outboard fuse pin, already weakened by a crack, to fail.

 

Since the El Al 747 crash, Boeing has redesigned new parts for the pylon-to-wing attachment for the engines.

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