AD 81-20-03

81-20-03 COSTRUZIONI AERONAUTICHE GIOVANNI AGUSTA: Amendment 39- 4247. Applies to Model A109A helicopters certificated in all categories with tail rotor drive shaft support bearings P/N 109-0424-01-1 installed (7 places). Compliance required as follows, unless already accomplished.

To prevent hazardous loss of directional control due to failure of a tail rotor drive shaft support bearing and subsequent failure of the tail rotor drive shaft, accomplish the following:

a. Before the first flight of each day after the effective date of this AD, visually check all seven tail rotor drive shaft support bearings, P/N 109-0424-01-1, for general condition, security, excessive play, slippage, or loss of lubricant. If any signs of damage, overheat, looseness, slippage, or loss of lubricant exist, the tail rotor drive shaft and all bearings and associated collars, retention rings, and dust boots must be further inspected and relubricated, or replaced as applicable, in accordance with steps 1, 2, 3, and 4 of Agusta Bollettino Tecnico No. 109-30, dated March 25, 1981, or an FAA-approved equivalent, prior to further flight.

b. Within the next 25 hours' time in service after the effective date of this AD and thereafter at intervals not to exceed 600 hours' time in service, inspect and relubricate, or replace as applicable, the tail rotor shaft, bearings, collars, and associated parts, in accordance with steps 1, 2, 3, and 4 of Agusta Bollettino Tecnico No. 109-30, dated March 25, 1981, or FAA-approved equivalent. Defective parts found during this activity must be replaced with serviceable like parts prior to further flight.

The daily check required by paragraph a. of this AD may be performed by pilots authorized under FAR 43.3(h) to perform preventative maintenance on this helicopter provided:

c. The pilot's logbook has been endorsed by a properly rated mechanic stating that the pilot has been trained to conduct the check required by this AD; andd. The rotorcraft is equipped with hinged inspection access panels located in the cooling fan cowl (for Nos. 1 and 2 bearings), over the tail boom section (for Nos. 3, 4, 5, and 6 bearings) and in the tail rotor vertical fin fairing (for No. 7 bearing). NOTE: Bearings are numbered from front to rear.

See FAR 91.173 for the requirements regarding the listing of compliance with paragraphs A and B of this AD in the aircraft's maintenance records.

Any equivalent method of compliance with this AD must be approved by the Chief, Aircraft Certification Staff, AEU-100, FAA, Europe, Africa, and Middle East Office, c/o American Embassy, Brussels, Belgium, or by the Chief, Engineering and Manufacturing Branch, Flight Standards Division, Southwest Region, Federal Aviation Administration, P.O. Box 1689, Fort Worth, Texas 76101.

Special flight permits may be issued in accordance with FAR 21.197 and FAR 21.199 to fly aircraft to a base where the inspections required by paragraph b. of this AD (initial compliance with Agusta Bollettino Tecnico No. 109-30) may be accomplished.

This amendment becomes effective November 12, 1981, for all persons except those to whom it was made immediately effective by priority mail AD No. 81-20-03 dated September 29, 1981.