Incident: British Airways A320 near London on Dec 18th 2014, fumes in cockpit and cabin

A British Airways Airbus A320-200, registration G-TTOB performing flight BA-326 from London Heathrow,EN (UK) to Paris Charles de Gaulle (France), was climbing out of Heathrow's runway 27R when fumes were detected in cockpit and cabin prompting both crew to don their oxygen masks, stop the climb at FL170 and return to Heathrow Airport for a safe landing on runway 27L about 30 minutes after departure.

The flight was cancelled.

The French BEA reported in their weekly bulletin that the occurrence was rated a serious incident and is being investigated by the AAIB. No injuries are being reported.

On Mar 12th 2015 the British AAIB released their bulletin reporting that hydraulic fluid leaking from a hydraulic actuator had been ingested by the air conditioning system.

The aircraft was climbing through 5000 feet when the flight crew noticed a "musty" smell in the cockpit, donned their oxygen masks and worked the related checklists. In the meantime cabin crew reported that the odour was noticed in the cabin as well and a couple of passengers reported being light headed and feeling nausea. As the check lists did not permit to identify the origin and the smell did not dissipate the crew decided to return to London, where the aircraft landed without further incident. After vacating the runway the smell had reduced sufficiently for the flight crew to remove their oxygen masks while taxiing to the apron.

Maintenance identified that a yaw damper actuator had been leaking hydraulic fluid which was ingested into the inlet of the auxiliary power unit (APU) from where the hydraulic fluid "found its way into the air conditioning system". The actuator was replaced and the decontamination conducted before the aircraft returned to service without further occurrences.