Aviation safety issues and actions

Fitment of bladder-type fuel tanks to R44 helicopters (US)

Issue number: AO-2013-055-SI-02
Who it affects: All owners and operators of R44 helicopters
Issue owner: United States Federal Aviation Administration
Transport function: Aviation: General aviation
Background: Investigation Report AO-2013-055
Issue release date: 04 June 2015
Current issue status: Closed – Not addressed
Issue status justification:

The ATSB notes and disagrees with the view of the United States Federal Aviation Administration (FAA) that accidents involving R44 helicopters without bladder‑type tanks do not result in a significantly higher proportion of post-impact fires than for other similar helicopter types. However, given the view of the FAA and the elapsed time since the safety recommendation was issued without advice of any safety action, the ATSB has closed the safety issue as not addressed.

Safety issue description

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.

Safety recommendation

Action number: AO-2013-055-SR-025
Action organisation: United States Federal Aviation Administration
Date: 04 June 2015
Action status: Released

The ATSB recommends that the United States Federal Aviation Administration take action to ensure that owners and operators of Robinson R44 helicopters comply with the manufacturer’s service bulletin SB-78B to replace all-aluminium fuel tanks with bladder-type tanks on Robinson R44 helicopters.

ATSB comment:

No response to this safety recommendation was received from the United States Federal Aviation Administration (FAA).

Last update 05 November 2020