Five Bombardier Dash 8-100 regional turboprops at Norway’s Widerøe’s Flyveselskap had undergone 80,000-flight cycle (FC) inspections by last month as part of an extended-service program (ESP) approved by Transport Canada and the European Aviation Safety Agency (EASA) in 2009. Of the 299 Dash 8-100s built, some 100 constitute the near-term market for the life-extension modifications, according to the manufacturer. Bombardier expects a further 128 will reach the 80,000-cycle threshold during the coming nine years.
Widerøe hopes to perform the work specified under the program–designed to increase service life on the -100 to up to 120,000 flight cycles–on another 10 airplanes before 2015. Part of the Scandinavian SAS airline group, Widerøe is the only airline to have operated every single variant of the Dash 8 series simultaneously, and one of the few operators to have flown all Dash 8 variants as well the former de Havilland Canada’s older DHC-6 Twin Otter and Dash 7.
Widerøe became the first operator to carry out the requisite comprehensive inspection at 80,000 flight cycles (the Dash 8’s original “design service goal”). The ESP will provide the aircraft with another 10 to 12 years of useful life, according to chief executive Lars Kobberstad, speaking when Bombardier launched the program four years ago, a quarter-century after the type’s entry into service.
The ESP involves compliance at 80,000 flight cycles with Bombardier service bulletin 8-05-03, which covers inspection and modification of the Dash 8-100 airframe structure and systems and monitoring of the model for another 40,000 flight cycles. The service bulletin considers the required aircraft configuration, structural and systems parts needed for replacement or on-condition inspection, post-modification testing and reliability reporting.
According to Bombardier, early Dash 8s undergoing 80,000-flight-cycle inspections have generated no significant maintenance findings. Before launching the ESP, the manufacturer reviewed all Dash 8-100 structural analyses, supported by laboratory studies of selected structural samples from a retired machine. For its part, Widerøe provided component- and systems-reliability data routinely through the Bombardier fleet statistics and reliability system and contributed other needed data.
The ESP requires replacement of about 100 components, including the horizontal stabilizer (on aircraft up to MSN 342), assorted actuators, manifolds, pressure switches, valves and other components. Widerøe does not foresee “a big market” for third-party ESP work.