AD 87-18-12 R1 ACTIVE

87-18-12 R1 McDONNELL DOUGLAS HELICOPTER COMPANY (MDHC) (Hughes Helicopter, Inc.): Amendment 39-5700 as amended by amendment 39-5800. Applies to all Model 369D, 369E, 369F, and 369FF helicopters, certificated in any category, incorporating main rotor transmission output shaft assembly ring gear carriers (P/N 369D25132-BSC or -5) in main transmission assemblies P/N 369D25100-BSC, -501 or -503.

Compliance is required as indicated unless previously accomplished.

To prevent possible loss of power to the main rotor, accomplish the following:

(a) For helicopters with metal particles found in the main transmission, excessive noise or vibration experienced in the main transmission, or vibrations felt in the aircraft that cannot be reduced or eliminated by ordinary main rotor blade tracking and balancing procedures, accomplish the inspection of paragraph (d) of this AD prior to further flight after the effective date of this AD and thereafter at intervals not to exceed 300hours time in service from the last inspection.

(b) For helicopters that have main transmission assemblies installed with less than 200 hours time in service on the output shaft assembly ring gear carrier on the effective date of this AD, accomplish the inspection of paragraph (d) of this AD prior to accumulating 300 hours time in service and thereafter at intervals not to exceed 300 hours time in service from the last inspection.

(c) For helicopters that have main transmission assemblies installed with more than 200 hours time in service on the output shaft assembly ring gear carrier on the effective date of this AD, accomplish the inspection of paragraph (d) of this AD within the next 100 hours time in service after the effective date of this AD and, thereafter, at intervals not to exceed 300 hours time in service from the last inspection.

(d) Perform a dye penetrant and visual inspection on the affected ring gear carriers in accordance with the procedures detailed inparagraphs a through g of the "Periodic Visual Inspection" section of McDonnell Douglas Helicopter Company Mandatory Service Information Notice (SIN) DN-148.1/EN-36.1/FN-25.1, dated October 30, 1987. Remove from service prior to further flight:''

(1) OutPut shafts with any bulging or raised surface in the area being inspected on the upper disc surface (see Figure 2 in referenced SIN).

(2) OutPut shafts with any crack indication in the area being inspected on the lower and upper disc surfaces (see Figure 3 in referenced SIN).

(e) When the main rotor transmission output shaft assembly ring gear carrier P/N 369D25132-3 is installed and the main transmission assembly is reidentified as P/N 369D25100- 505, repetitive inspections are no longer required.

(f) Alternative inspections, modifications, or other actions which provide an equivalent level of safety may be used when approved by the Manager, Western Aircraft Certification Office, Hawthorne, California.

(g)Special flight permits may be issued in accordance with FAR sections 21.197 and 21.199 to ferry aircraft to a maintenance base in order to comply with the requirements of this AD.

The procedure shall be done in accordance with MDHC Mandatory Service Information Notice DN-148.1/EN-36.1/FN-25.1, dated October 30, 1987. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from McDonnell Douglas Helicopter Company, 500 E. McDowell Road, Mesa, Arizona 85205. Copies may be inspected at the Office of the Regional Counsel, FAA, Southwest Region, 4400 Blue Mound Road, Fort Worth, Texas, or at the Office of the Federal Register, 1100 L Street, NW., Room 8401, Washington, D.C.

This amendment 39-5800 amends Amendment 39-5700 (52 FR 33228; September 2, 1987), AD 87-18-12.
This amendment 39-5800 becomes effective January 15, 1988.