Air Force Lebanese Air Force Mexican Navy Nicaraguan Air Force Peruvian Army Philippine National Police Air ambulances in Poland Forest Protection Service South African Police Service Air Wing Royal Thai Army Alaska State Troopers Police of Uruguay Accidents and incidents Fuel tanks The R44 was found to be prone to post-accident fires due to damage to the aluminum fuel tanks, allowing fuel to leak out. In 2009, the company began installing bladder-type fuel tanks in all new R44 helicopters. It also issued Service Bulletin SB-78 on 20 December 2010, requiring R44 helicopters with all-aluminum fuel tanks to be retrofitted with bladder-type tanks to "improve the R44's fuel system's resistance to a post-accident fuel leak." The company recommended that the change should be done as soon as practical, but no later than 31 December 2014. The compliance date was later moved to 30 April 2013. An accident investigation by the Australian Transport Safety Bureau (ATSB) in March 2013 found, after analyzing historical data, that a significantly higher proportion of R44 aircraft (12%) caught fire after crashing, compared to accidents involving other types of piston-engine helicopters (7%). Preliminary analysis by the ATSB of the NTSB's accident database found a similar statistic, with 15% of accidents in the US involving R44 helicopters having post-crash fires. Although the data did not consider which type of fuel tanks were fitted, the report mentioned four fatal accidents to the R44 fitted with bladder-type tanks, but as far as they knew, did not involve a post-accident fire. The ATSB recommended that the Australian Civil Aviation Safety Authority (CASA) take further action to urge R44 owners to fit bladder-type tanks. The FAA, the governing body in the country of manufacture whose directives would normally be followed in other countries like Australia, had not mandated the retrofit; CASA therefore issued Australian-specific airworthiness directive AD/R44/23, grounding R44 aircraft on 30 April 2013 that had not yet been upgraded. Rotor failures On 19 February 2015, the New Zealand Civil Aviation Authority issued an Airworthiness Directive grounding 80 of the country's R44 helicopters after two people were killed in an accident traced to a particular type of main rotor blade, the P/N C016-7 or Dash 7, which a preliminary investigation determined had failed in flight. It was the second failure or partial failure in two months. This was the largest-scale grounding of any aircraft in New Zealand's history. The CAA determined through