Easyjet A320 at Milan on Aug 12th 2013, engine doors torn off

Last Update: December 11, 2016 / 18:11:42 GMT/Zulu time

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Incident Facts

Date of incident
Aug 12, 2013

Classification
Incident

Airline
Easyjet

Flight number
U2-2715

Departure
Milan Malpensa, Italy

Destination
Lisbon, Portugal

Aircraft Registration
G-EZTC

Aircraft Type
Airbus A320

ICAO Type Designator
A320

An Easyjet Airbus A320-200, registration G-EZTC performing flight U2-2715 from Milan Malpensa (Italy) to Lisbon (Portugal) with 169 passengers and 6 crew, was in the initial climb out of Malpensa's runway 35R when the left hand engine's (CFM56) doors opened and were subsequently torn off the engine. The crew stopped the climb at about 3500 feet and returned to runway 35L for a safe landing about 10 minutes later.

Italy's ANSV have opened an investigation into the occurrence rated a serious incident reporting that debris off the engine doors also caused damage to the aft fuselage and tailplane.

In their annual bulletin released on Apr 30th 2014 Italy's ANSV reported the panels opened in a position close to rotation for takeoff. The aircraft received impact damage at the left hand fuselage and to the left hand slat #1 as well as a significant distortion of the engine pylon. The debris left behind on the runway as well as analysis of the fragments permitted to reasonably conclude the serious incident was caused by the failure to lock the access doors at the end of a scheduled maintenance check that had been done shortly before departure.

The ANSV found compelling similiarities with the accident at London Heathrow, see Accident: British Airways A319 near London on May 24th 2013, unlatched doors on both engines separated, fuel leak, engine on fire shut down. Subsequent research identified a total of 35 similiar occurrences, equally distributed between CFM56 and IAE V2500 engines. The ANSV is therefore in direct contact with the AAIB investigating the occurrence at London to develop a coordinated plan of action and subsequently organize a joint meeting at EASA, European Aviation Safety Agency responsible for certification of Airbus products, to explore EASA's intentions.

On Dec 7th 2016 Italy's ANSV released their final report in Italian concluding the probable causes of the incident were:

The causes of the incident are mainly the result of human factors.

In particular the left hand engine doors were left open due to failure of closing them after maintenance work was completed without consulting the technical reference manual. The failure to consult the technical reference manual and follow the instructions in there meant, that the engine doors were opened prior to the maintenance work conducted but then not closed and locked again.

The preflight inspection carried out by the commander of the aircraft also proved ineffective having not been performed in compliance with the operator's standard operating procedures.

Following factors also contributed:

- the shape of the door locking system, which in fact is characterised by a non fault tolerant design not facilitating the inspections to verify the doors are closed and locked. Especially the levers of the locking system are located at the bottom center of the engine cowlings and are hardly visible. In addition the cowlings feature a symmetry that permits the doors to become almost seated and no longer indicate open even if not locked.

- the policies and operating procedures by the maintenance organisation did not require to have the technical reference manual available in the close proximity of the aircraft at all time while conducting the maintenance work

- the lack of warning indications on the ECAM that the engine doors were not locked

Finally, the investigation can not rule out that the ocurrence was the result of tiredness and fatigue on behalf of the maintenance technician as well as the captain in an environment that was characterized by high outdoor temperatures. The level of contentration by the maintenance technician may also have been adversely affected by the fact that he was close to the end of his scheduled work time following 4 days of programmed work.

The ANSV reported that tower and the crew of another aircraft observed the aircraft rotating for takeoff when the left hand engine doors separated. A few seconds after becoming airborne both tower and crew relayed their observations to the crew of the A320. Cabin crew of the A320 also contacted the flight deck reporting abnormal noise during takeoff and watching the reactions of the passengers were alerted of the left engine cowling departing the aircraft. The crew advised of their intention to immediately return to Malpensa for an overweight landing, used both engines normally for positioning the aircraft and landing, during roll out used both engine thrust reversers, during the roll out further parts of the engine cowling dropped off the aircraft.

The ANSV analysed that the maintenance work was done in daylight conditions and thus would have easily permitted to verify the status of the latches of the engine cowl. However, the outdoor temperatures at 30 degrees C may have negatively affected the performance by both the maintenance technician as well as the captain, who subsequently performed the preflight inspection and needed to verify the latches under the engine.

Analysis of the latches and locking system did not reveal any evidence of a technical failure, all bolts and latches were found intact. The testimony by the maintenance technician as well as the technical analysis of the recovered engine doors permit to conclude that the doors were not closed and latched during departure.

The position of the latches is just 50cm from the ground at the underside of the engine requiring a person verifying the status of the locks to kneel down or squat. The absence of any indication in the cockpit also does not draw the attention to unlocked engine doors. In the specific case of G-EZTC a poor colour contrast of the hook with yellow colour to the orange colour of the engine cowling made it even less evident, that the hooks were not latched. In addition, the gap between the door and surrounding cowling is very small with the latches engaged but not locked making the door appear almost flush with the engine cowl even if the hooks are not latched.