Incident Overview
On 15 December 2008 at 2123 hrs UTC, an Airbus A319-111 (registration G-EZDM) operated by a commercial airline experienced a serious incident shortly after takeoff from Paris Charles de Gaulle Airport. The aircraft had 6 crew and 130 passengers on board; no injuries were reported. The damage consisted of a severed hydraulic line.
Sequence of Events
After takeoff, the pilot not flying selected the landing gear up but received an Electronic Centralised Aircraft Monitor (ECAM) message indicating that the main landing gear doors were not closed. Air traffic control was advised of the problem and that the speed would be kept low. The ECAM procedure for this failure was performed without success. At 1,500 ft agl, further ECAM messages appeared: a Green hydraulic system 'fluid low contents' caption and a Yellow system 'fluid reservoir overheat' caption. The crew performed the associated drills, which included switching off the Yellow system engine-driven pump (EDP) and the power transfer unit (PTU), placing the aircraft into single-system hydraulic operation.
A MAYDAY call was made, and the crew requested radar vectors for landing. Shortly after completing the ECAM actions, the Yellow system overheat caption cleared, and the EDP was reselected, restoring hydraulic pressure in that system. The commander briefed the senior cabin crew member and advised passengers to prepare for a precautionary landing. Due to low-visibility procedures at Paris CDG caused by low cloud, a Category IIIA instrument landing was performed. The landing was uneventful, and the commander requested and received a fire service escort to the gate, where passengers disembarked normally.
Engineering Findings
Examination revealed that the flexible hose for the left main landing gear 'door close' actuator was damaged and leaking. Both the 'door close' and 'door open' hoses were replaced; the latter was also found worn. The hydraulic systems were inspected, replenished as necessary, and found serviceable. Analysis showed that after liftoff, when the landing gear was selected up, the 'door close' hose ruptured, depleting the Green hydraulic system contents. As Green system pressure dropped, the PTU automatically switched on, but due to the fluid loss, it overheated after about two minutes. Cautions for the low fluid level and overheat were inhibited below 1,500 ft agl by design to avoid pilot distraction.
Post-Incident Actions
The operator imposed a 6,000 flight cycle life on the hoses until the aircraft manufacturer devises an engineering solution. The manufacturer issued Service Bulletin 29-1115 to introduce modifications, including inhibiting automatic operation of the PTU below 1,500 ft. Further modifications are in Service Bulletin 29-1126, which activates the inhibition logic. New aircraft have the first modification embodied, but the activating logic remains optional; the manufacturer encourages retrofit.