Emergency AD on Tail Rotor for Agusta AW139

This Emergency Airworthiness Directive (AD) 2011-18-52 is prompted by a fatal accident involving an Agusta Model AW139 helicopter, which may have been caused by cracks in a tail rotor (T/R) blade. This condition, if not detected and corrected, could result in failure of a T/R blade, and subsequent loss of control of the helicopter.

Within 5 hours time-in-service (TIS), establish a life limit of 600 hours TIS or 1,500 takeoff and landing cycles (cycles), whichever occurs first, on the affected T/R blades and update the helicopter’s historical records. If a T/R blade’s total number of cycles is unknown, determine the T/R blade cycles by multiplying the T/R blade’s hours TIS by 4.

For a T/R blade that, on the effective date of this AD, has already exceeded 600 hours TIS or 1,500 cycles, within 5 hours TIS replace the T/R blade with an airworthy T/R blade.

Within 25 hours TIS, and thereafter at intervals not to exceed 25 hours TIS, visually inspect the T/R blade for a crack or damage that exceeds the limits of the applicable maintenance manual. Inspect the T/R blade using a mirror, magnifying glass (5X or greater), and light source; or borescope.

If there is a crack, or if there is damage that exceeds the limits of the applicable maintenance manual, before further flight, replace the T/R blade with an airworthy T/R blade.

pdf icon2011-18-52_emergency.pdf

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