Accidents involving Robinson R44 helicopters without bladder-type tanks fitted result in a significantly higher proportion of post-impact fires than for other similar helicopter types. In addition, the existing United States regulatory arrangements are not sufficient to ensure all R44 operators and owners comply with the manufacturer's Service Bulletin SB-78B and fit these tanks to improve resistance to post-impact fuel leaks.
Response to the safety issue by the United States Federal Aviation Administration
The Federal Aviation Administration (FAA) advised that, based on the results of their own analysis, and a belief that the ATSB’s analysis methodology was invalid, they fundamentally disagreed with the ATSB’s conclusion that accidents involving R44 helicopters without bladder-type tanks resulted in a significantly higher proportion of post-impact fires (PIF) than for other similar helicopter types. As such, no advice of safety action was provided by the FAA in response to this safety issue.
ATSB action in response
Following receipt of this advice from the FAA, the ATSB reviewed its PIF analysis methodology. The review concluded that the method used by the ATSB to analyse PIF occurrences, and the resulting conclusion that R44 helicopters without bladder-type tanks fitted result in a significantly higher proportion of PIF than for other similar helicopter types, were valid.
As a result, the ATSB issued the following safety recommendation.