Lufthansa has been working for more than a year on measures to avoid oil fumes in the cabin air of its Airbus A380 fleet, and it plans to introduce onboard equipment to measure potential contamination levels on an ad hoc basis.
The German airline has experienced a number of incidents where odours occurred in the cabin air of its Rolls-Royce Trent 900-powered A380s. It cautions, however, that it is not clear whether all of the events involved engine oil fumes.
Lufthansa declined to specify the number of incidents when asked for further details, but it tells Flightglobal that they happened on multiple aircraft. The company adds that it has been focussing on the issue for "more than a year".
Rolls-Royce says that cabin odours occurred on a "small number" of flights on the double-decker aircraft.
Singapore Airlines, which also selected the Trent engines for its A380 fleet, says it has not observed any such incidents. Fellow Trent operator Qantas could not be immediately reached for comment.
Lufthansa asked Rolls-Royce to develop a modification, which has now been installed on several engines in the airline's 10-strong A380 fleet.
The modification comprises a cover for the bleed air extraction outlet, which should stop oil particles from entering the cabin air system. It is based in principle on a similar shield that was developed for Trent 500 engines on the Airbus A340-600 several years ago, says Lufthansa.
The cabin odour issue appears to arise during engine start-up. Lufthansa is developing a new start-up procedure together with Airbus and Rolls-Royce, whereby the bleed air supply to the cabin will be temporarily interrupted as the engines spool up.
This procedure has not yet been approved, however. In the meantime, the airline says, its technicians are manually cleaning the affected engine areas at short intervals to avoid any residual oil outside the regular lubrication system.
Lufthansa concedes that oil can enter the cabin air system under "adverse circumstances" when the regular safeguards are not fully reliable. If small oil quantities drip on hot surfaces, the synthetic lubricant can thermally decompose and thus release tri-ortho cresyl phosphate (TOCP), a toxic isomer of the tricresyl phosphate (TCP) oil additive.
But the airline says that TOCP has never been determined in cabin air samples. It adds that the company's in-house medical examiners have not documented any case where flight or cabin crew showed neurological symptoms, which could be based on contaminated cabin air.
Lufthansa considers the issue a matter of comfort. It says there is no scientifically sound data that shows which substances occur; measures air contamination levels during a smoke incident; and demonstrates "whether there is a causal link between fumes and illnesses".
Nevertheless, the carrier has contracted German research centre Fraunhofer Institute to develop portable measuring equipment to determine cabin air contamination levels if suspicious odours occur. Due to the high cabin air recycling rate onboard aircraft, retrospective measurement after an event would be futile, the airline says.
Lufthansa says it will introduce the equipment on its own initiative and that it is has not been deployed in cooperation with, for example, EASA, German regulator LBA or air accident investigation bureau BFU.