Aviation safety issues and actions

Fitment of rubber, bladder-type fuel tanks to R44 helicopters

Issue number: AO-2013-055-SI-01
Who it affects: All owners and operators of R44 helicopters
Issue owner: Civil Aviation Safety Authority (CASA)
Transport function: Aviation: General aviation
Background: Investigation Report AO-2013-055
Issue release date: 27 March 2013
Current issue status: Closed – Adequately addressed
Issue status justification:

AD/R44/23 R44 Bladder Fuel Tank Retrofit by CASA mandated the fitment of bladder type fuel tanks in Australian-registered R44s in accordance with SB-78B.

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 Australian regulatory arrangements were not sufficient to ensure all R44 operators and owners complied with the manufacturer's Service Bulletin SB-78B and fitted these tanks to improve resistance to post-impact fuel leaks.

Proactive action

Action number: AO-2013-055-NSA-002
Action organisation: Civil Aviation Safety Authority
Date: 27 March 2013
Action status: Monitor

On 27 March 2013, CASA stated:

CASA has highlighted to registered operators the operation of CAR 42A. At page 1.1 of the Robinson Maintenance Schedule it states Service Bulletin compliance is mandatory. Registered operators of R44 helicopters who have elected, or are otherwise required, to use the manufacturer’s maintenance schedule must comply with the abovementioned SB’s by 30 April 2013. If they do not, the aircraft cannot be flown.

and that:

CASA will also, as soon as possible, write to all operators of Robinson R44 helicopters to identify if any of them are subject to an approved system of maintenance that does not include a requirement to comply with service bulletins. If any such systems do not contain such a requirement, CASA will consider directing that the system be changed under CAR 42Q to require compliance with service bulletins.

ATSB comment:

Date: 03 April 2013

The ATSB noted that Australian owners and operators of Robinson R44 aircraft had shown a greater rate of compliance with the manufacturer’s Service Bulletin SB-78B than had occurred on a worldwide basis. The ATSB also noted CASA’s understanding that existing regulatory requirements were such that compliance with SB-78B was already mandatory for the vast majority of R44 helicopters in Australia. However, the ATSB remained concerned that a significant number of Australian owners and operators had not yet taken steps to comply with the service bulletin and were therefore very unlikely to be able to comply by the required date of 30 April 2013.

Safety recommendation

Action number: AO-2013-055-SR-001
Action organisation: Civil Aviation Safety Authority
Date: 03 April 2013
Action status: Released

The ATSB recommends that CASA take further action to ensure that owners and operators of Robinson R44 helicopters are aware of the relevant regulatory requirements and comply with the manufacturer’s service bulletin SB-78B to replace all-aluminium fuel tanks with bladder-type tanks on Robinson R44 helicopters.

Additional correspondence

Response date: 05 April 2013
Response from: Civil Aviation Safety Authority
Action status: Closed
Response text:

On 5 April 2013, CASA advised the ATSB of the following additional safety actions to address the safety issue.

CASA published Airworthiness Bulletin (AWB) 02-44 on its website on 3 April 2013. The bulletin stated that:

Registered operators of Robinson R44 helicopters that are maintained using the manufacturer’s maintenance schedule are reminded that they must comply with Service Bulletins by their due date. The registered operator will be contravening regulation 41 of the CAR [Civil Aviation Regulations] and the pilot and registered operator may also contravene regulation 47 of the CAR if they do not comply with Service Bulletins by their due date.

If the helicopter is maintained to an approved SOM [System of Maintenance] then the SOM must have consideration for compliance with Robinson Helicopter Company Service Bulletins. With regards to Robinson Helicopter Company Service Bulletins mentioned in AWB 28-012, CASA would regard an SOM that does not include these Service Bulletins as deficient.

In addition, on 28 March 2013 CASA sent a Direction, Instrument number CASA 47/13, to all R44 operators requiring them to notify CASA if their helicopters were maintained in accordance with a SOM as opposed to maintenance in accordance with the helicopter manufacturer's US Federal Aviation Administration-approved maintenance program. The Direction stated that CASA would mandate the compulsory incorporation of Service Bulletins (SBs) if individual SOMs did not already do so. The Direction also notified that for those R44 helicopters maintained in accordance with the manufacturer's maintenance program (the vast majority), the operator must install the SB-78B modification by 30 April 2013 to be able to legally operate after that date.


Response date: 29 April 2013
Response from: Civil Aviation Safety Authority
Action status: Closed
Response text:

On 29 April 2013, CASA issued Airworthiness Directive AD/R44/23 (R44 Bladder Fuel Tank Retrofit), which required Australian operators of R44 aircraft to comply with the Robinson Helicopter Service Bulletin SB-78B. The AD stated that ‘the SB must be complied with before further flight after 30 April 2013’. The background section stated:

This Airworthiness Directive requires R44 helicopters fitted with all-aluminium fuel tanks to be retrofitted with bladder-type tanks, to improve the R44 fuel system’s resistance to a post-accident fuel leak. Recent post-crash fires in Australia have prompted CASA to mandate compliance with [the] manufacturer’s service bulletin to reduce the risk of further post-crash fires and increase survivability of such an event.

Aircraft which are maintained in accordance with the Manufacturer’s Maintenance Schedule are already required to comply with all Robinson Service Bulletins by regulation 42A of the CAR.  

ATSB comment date: 30 April 2013
ATSB comment:

The ATSB is satisfied that CASA’s additional safety actions will significantly reduce the residual risk associated with the number of R44 helicopters likely to be operating in Australia after 30 April 2013 that have not installed the bladder-type fuel tanks in accordance with Service Bulletin SB‑78B.

Last update 05 November 2020