FAA has published an emergency airworthiness directive (AD) related to the tail boom of the AgustaWestland AW139 and AB139. According to a European Aviation Safety Agency (EASA) mandatory continuing airworthiness information (MCAI) alert, the tail boom of a Gulf Helicopters-operated AW139 bent and collapsed while taxiing on August 25 in Doha, Qatar. In addition, EASA discovered “evidence of debonding on some tail boom panels,” on the AW139 and AB139.
|The tail boom of this Gulf Helicopters AgustaWestland AW139 broke off while taxiing on Aug. 25 in Doha, Qatar.|
According to AgustaWestland, which dispatched a technical team to inspect the helicopter, “no similar occurrence has taken place with any other AW139.” Qatar’s Civil Aviation Authority (QCAA) is allowing AgustaWestland to conduct the investigation at its lab in Cascina Costa, Italy, under its supervision and with an Italian National Agency for Flight Safety (ANSV) representative present. While the investigation is ongoing, AgustaWestland has published two technical bulletins. Initial findings indicate that pre-existing and undetected damage on the Gulf AW139 tail unit may have contributed to the incident, the company says.
The helicopter in question apparently experienced a tail strike in March 2009 while taking off from an oil rig platform, according to the manufacturer. The FAA emergency AD took effect on Sept. 16 immediately after being issued. The U.S. regulatory agency is requiring more frequent inspections of the tail panels and measures designed to uncover potentially unsafe conditions. Included are instructions on how to identify evidence of debonding along the tail boom surface using a specific type of aluminum hammer.