In a helicopter the articulated head and tail rotor gearbox are required to be a very high specification design using the best materials and requiring frequent and costly maintenance.

在直升机的阐述头和尾桨变速箱都必须是一个非常高规格的设计使用最好的材料和需要频繁和昂贵的维修。

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It included the black box flight recorder, the fuselage with the engines and rotor gearbox attached, the separated rotor head with the main rotor blades still attached, and the separated tail.

BBC: Crash report urges safety checks