Air Berlin cut the average specific fuel consumption of its fleet to 3.5 litres per 100 passenger kilometres in 2011 through a number of technical and operational performance improvements.
The German airline claims it now has the lowest per-service fuel consumption of any network carrier in Europe.
Intervals for engine washes, which the company conducts through its in-house maintenance division Air Berlin Technik, have been cut from 1,500 flight cycles to between 500 and 1,000 cycles depending on aircraft type, said Felix Genze, head of performance improvement.
Interval length varies depending on the price of jet fuel as the additional cost of extra washes needs to be balanced by the fuel saving.
Genze said that Air Berlin recently introduced an evaluation system which focuses on aerodynamic losses due to the rigging of individual aircraft. Maintenance items such as worn seals or gaps and steps in wing flap assemblies, which are not safety critical and were previously categorised as tasks for the next scheduled airframe check, now gain greater priority based on the respective efficiency gains.
This includes, for example, certain inoperable bleed air system components, which could have been referred under the minimum equipment list (MEL) in the past if the aircraft cruised on a lower flight level, but which would have reduced fuel efficiency.
Air Berlin has installed zonal driers in approximately 40% of its aircraft to avoid water accumulation in the airframe insulation material and thus reduce weight, said Genze. A fleet-wide employment of the equipment is not planned, however, as condensation varies on different aircraft and depends on their individual operation.
Lightweight service trolleys, which were initially introduced on the airline's Airbus A330 long-haul fleet, will be rolled-out across all aircraft throughout this year.
The airline has improved performance monitoring for its Airbus fleet to determine the aerodynamic losses for each individual aircraft during the descent stage of flight with idling engines. This idle factor can be programmed into the flight management and guidance computer (FMGC) to determine the optimal top-of-descent point where the crew reduces power for approach to the destination.
While this function has been available in the FMGC, it has not previously been employed due to the unavailability of the required data.
At the end of 2011, Air Berlin began to supply its pilots en route with flight plan updates for more efficient navigation. These are transmitted directly to the flight management system via the aircraft communications addressing and reporting system (ACARS).
This falls in line with the airline's strategy to supply its flight crew with meteorological and aeronautical information as closely as possible to departure to determine the optimal flight profile.
The first months of the en route update procedure have shown fuel savings of between 0.5% and 2%, said Genze.
Air Berlin's fuel-saving initiative is in-line with the International Air Transportation Association's target to make fuel efficiency improvements of 1.5% per year until 2020.
This year Air Berlin aims to reduce its average SFC to 3.4 litres per 100 passenger kilometres.