Mid-air jet failure sparks probe
Parts fatigue and over-stress blamed for 'serious incident' that grounded plane for two weeks
The Air Accident Investigation Unit (AAIU) of the Department of Transport is investigating a "serious incident" involving an Aer Lingus flight that suffered a double wing component failure while flying 33,000 feet over the North Atlantic.
The incident occurred on May 11 last as Aer Lingus flight EI125 was en route from Dublin to Chicago. The Airbus 330-300 jet, which was carrying 227 passengers and crew, was north of Iceland when the failure occurred. The crew received no warning, while passengers are also understood to have remained unaware of the drama.
During a post-flight inspection, it was discovered that two aileron actuator castings had completely fractured during the flight. A preliminary examination of the parts, photos of which have appeared on an online pilots' forum, has indicated that one casting fractured due to fatigue while the other may have failed due to over-stress.
The return flight to Dublin was cancelled as a result of the failure, and the jet remained grounded in Chicago for over two weeks so that repairs could be undertaken.
Aer Lingus has confirmed that aircraft manufacturer Airbus had advised it previously that two of its aircraft could potentially have had the same problem. Both were inspected and no fault was found.
After the May 11 incident, both aircraft were again checked and no defect was discovered.
The matter has been "classified as a serious incident".
The AAIU has stated: "The aircraft did encounter moderate turbulence at the time but this is not believed to be the initiator of the failure."
When the failure occurred, there was no noise or aircraft-generated warning, and it was not detected by the crew for some time. It is believed the failure may have occurred up to seven hours before landing.
"The aircraft developed an abnormal system condition that required rectification at Chicago before further flight," according to an Aer Lingus spokesperson.