Air Berlin has developed a software tool to evaluate irregularities on aircraft exterior surfaces as part of efforts to cut fuel costs.

The German low-cost airliner's auditing program guides technicians through a standardised aircraft-inspection procedure to find potential sources for increased aerodynamic drag, such as small skin dents, rough paintwork or excessive gaps in landing doors and flight-control surfaces.

The software helps technicians to measure and classify any findings. It then calculates the fuel-efficiency losses and draws up a priority list specifying which flaws should be rectified during the next maintenance check.

No such software has been available to date, says Air Berlin.

The carrier has introduced dedicated inspectors who check the aircraft’s exterior for potential sources of increased drag.

The software has so far been employed on a total of 15 Airbus A320 and A330 aircraft for one-off checks, says the airline.

Air Berlin plans to roll out the tool to other types in its approximately 140-strong fleet and conduct the inspections periodically in future.

However, interval lengths for the inspections have not yet been determined. They will depend on operational experience of how quickly the surface optimisations deteriorate, the airline says.