European aircraft operators and manufacturers are being reminded to ensure they have adequate processes in place to check and maintain flight data recorders (FDR) and cockpit voice recorders (CVR)—part of a broader effort to upgrade recorder standards in light of problems encountered during recent accident probes.
A European Aviation Safety Agency (EASA) safety information bulletin (SIB) issued in early January targets so-called “dormant” recorder failures caused by any number of issues. The problem arises when routine tests do not warn pilots or mechanics that the recorders are not working and the issue is discovered during a subsequent accident or incident probe involving the aircraft.
“Safety investigation authorities have reported several cases in which the FDR or CVR have not recorded data as expected, due to a malfunction of the unit or the dedicated equipment,” EASA notes. “Such failures may remain hidden for a certain amount of time, as it is difficult or impossible to determine the full system functionality on board the aircraft.”
EASA also noted cases of poor data quality, either due to equipment malfunctions or issues tied to translating raw data into filtered data.
The SIB recommends that operators closely follow recommended in-service practices, including regular tests of the devices and inspecting data and voice recordings to ensure the information being captured is of acceptable quality standards.
The SIB goes hand-in-hand with broader air operations rules issued in 2012 and effective as of late 2014.
In addition to the broad requirements for in-service recorders, EASA in a separate rulemaking mandated that many classes of operators install CVRs with longer durations—20 hr. for large aircraft—and that older-technology magnetic tape recorders be phased out by the end of the decade.
In analyzing the problems with in-service recorders, EASA determined that 24% of magnetic tape CVRs deliver insufficient recording quality, while about 35% of magnetic tape FDRs will not capture all the data they are designed to record. By comparison, only about 5% of solid-state recorders have similar problems, the regulator found.
The rulemaking, fast-tracked following the disappearance of Malaysia Airlines Flight 370, suggests that about 2,500 aircraft—including helicopters—may need recorders upgraded to stay in service beyond the rule’s deadline. EASA estimates that about 21% of worldwide aircraft with maximum takeoff weights of at least 5,700 kg (12,500 lb.) have magnetic tape CVRs, and 12% have magnetic tape FDRs. The percentages are slightly higher in Europe at 30% and 20%, respectively, EASA said. Costs of €25,000-35,000 ($29,000-40,000) per recorder installation would be largely offset in short order by the decreased inspection requirements of solid-state technology, EASA suggested in the rulemaking.
In the U.S., FAA’s last major recorder rule was issued in 2008. Among its requirements: increased sampling rates for digital FDRs and independent power sources for CVRs.