88-05-01 R1 SIKORSKY AIRCRAFT: Amendment 39-5856 as revised by Amendment 39- 6637. Docket No. 88-ASW-4.
Applicability: Sikorsky Aircraft Model S-76B helicopters, Serial Numbers (S/N) 760312, 760314, 760316, 760317, 760318, 760319, 760327, 760330, 760331, and 760337, certificated in any category, equipped with the original cross beam cap angle, Part Number (P/N) 76070-20526-102, and the original cross beam web, P/N 76070-20526-139, -149, or -158.
Compliance: For helicopters with 300 or more hours' time in service, compliance is required within the next 50 hours' time in service after the effective date of this amended AD, and thereafter at intervals not to exceed 50 hours' time in service from the last inspection.
To prevent failure of the helicopter forward engine support cross beam, accomplish the following:
(a) Visually inspect the forward engine support cross beam cap angle and web as follows:
NOTE: The forward engine support cross beam is accessedby opening the engine air inlet/bypass cowl per Sikorsky Supplemental Maintenance Manual SA4047-76B-2, Section 53- 20-03. The cross beam is located towards the rear of the inlet area opening and extends across the fuselage. The beam is attached to the engine compartment deck and the engine forward mount fittings are attached to the cross beam upper cap angle. If the cross beam cannot be inspected properly from the inlet area because of interference with existing components, remove the main transmission drain access panels in the baggage compartment overhead.
(1) Clean the forward surface of the cross beam as much as possible with dry cleaning solvent P-D-680, Type II, or equivalent.
(2) Visually inspect, using a flashlight and mirror as necessary, the forward side of the upper cross beam cap angle and web for evidence of cracks.
NOTE: Particular attention should be directed to areas under the inboard engine support fittings.
(b) If cracks are detected visually, verify cracks by using a dye penetrant or equivalent inspection method.
NOTE: Method Type II in MIL-STD-6866 is an acceptable inspection method.
(1) If cracks are found in the cap angle, replace cracked part prior to further flight with a new part of the same part number.
(2) If cracks are found in the web, prior to further flight, either replace the cracked part with a new part of the same part number or repair cracks found as a result of this AD with a method approved by the Manager, FAA, Boston Aircraft Certification Office.
(c) Report cracks found, including location, length, fasteners and holes affected, replacement of parts, and total time in service on helicopter, by letter, to the Manager, Boston Aircraft Certification Office, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803, within 10 days of the inspection. (Reporting approved by the Office of Management and Budget under OMB No. 2120-1156.)
(d) Aircraft may be ferried in accordance with the provisions of the Federal Aviation Regulation (FAR) Sections 21.197 and 21.199 to a base where the AD can be accomplished.
(e) Alternate inspections, repairs, modifications, or other means of compliance which provide an equivalent level of safety may be used if approved by the Manager, Boston Aircraft Certification Office, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803, telephone (617) 273-7118.
(f) Upon submission of substantiating data by an owner or operator through an FAA maintenance inspector, the Manager, Boston Aircraft Certification Office, may adjust the compliance time specified in this AD.
This AD revises AD 88-05-01, Amendment 39-5856 (53 FR 5366, February 24, 1988).
This amendment (39-6637, AD 88-05-01 R1) becomes effective on July 16, 1990.