Finnish investigators are recommending that the interval between inspections of flight recorders be shortened after the examination of an ATR 42-500 damaged in a runway incident revealed that the digital flight-data recorder had suffered a complete failure.
The Finncomm Airlines turboprop briefly veered off the left side of runway 32 while landing at Seinajoki Airport, in gusting crosswinds, on 11 December last year. Its left main gear struck two runway edge lights, which cut the aircraft's anti-skid wiring.
None of the 27 passengers and three crew was injured. But investigators from the Accident Investigation Board of Finland (AIBF) found that, during the inquiry, they were unable to download information from the flight-data recorder. Specialists from both the Finnish agency and the French Bureau d'Enquetes et d'Analyses tried to retrieve the data but failed.
The solid-state Fairchild FA2100 device was sent to its manufacturer, US-based L-3 Communications, which concluded that the recorder had suffered a "catastrophic failure" in its power supply - causing the loss of several circuit boards, including the crash-survivable memory unit - and that recovery would be impossible.
"Missing [flight-recorder] data hampered the investigation," says the AIBF. "Furthermore, some of the details of the incident had to be inferred. AIBF has encountered recorded time and location errors in two previous investigations of the same company. The company was not aware that the [recorder] was malfunctioning."
AIBF says the manufacturer required the device to be tested every 4,000h - equating to two years in the carrier's operations - but the ATRs had been in the Finncomm fleet for only a year when the incident occurred, stating: "In other words, the company did not overlook the [recorder's] inspection cycle."
The investigation board says the 4,000h interval is "too long" and stresses that the information contained in flight recorders is "invaluable" to analysing an accident or incident.
AIBF is recommending that the European Aviation Safety Agency investigate the prevalence of flight-data recorder malfunctions and, depending on the results, consider shortening the maintenance cycle to ensure continuous functioning.
Source: Flight International
