AD 76-07-07

76-07-07 CESSNA: Amendment 39-2568. Applies to Model 421C (Serial Numbers 421C0003 thru 421C0052 (except 421C0008, 421C0017, 421C0019, 421C0026, 421C0039, 421C0045, 421C0046 and 421C0048) airplanes.

Compliance: Required as indicated, unless already accomplished.

To prevent leakage of fuel and an engine nacelle fire:

A) Prior to the next and each subsequent flight, accomplish the following:

1. Visually inspect the P/N S1129-03-0304 hose assembly located in the right hand engine nacelle (see Item No. 63 in the 1976 Cessna Model 421C Parts Catalog, Pages 7-10, Fig. 1) in the area where this hose assembly routes under the exhaust manifold near the waste gate "Y".

2. Should whitening or general deterioration of the fire sleeve around the hose be noted, remove the sleeve and visually inspect the hose for hardening, cracks, seepage, etc. If any of these conditions are noted, replace this hose with a new hose routed so that a minimum of four inches between anyexhaust system surface and the hose is maintained. If the hose is satisfactory, install a new fire sleeve or reinstall the existing fire sleeve so that the whitened or deteriorated area of the sleeve is not in the original location on the hose. Except for those aircraft utilized in air carrier service, the inspection of the fire sleeve for whitening or deterioration may be accomplished by a holder of a pilot's certificate issued under Part 61 of the Federal Aviation Regulations on any aircraft owned or operated by him. If the whitened or deteriorated condition is noted, the inspection of the hose and the correction of any unsatisfactory conditions found must be accomplished by a certificated powerplant mechanic.

3. An equivalent hose assembly may be field fabricated and installed if a factory hose is unavailable.

B) Within 25 hours' time in service after the effective date of this AD, replace the original P/N S1129-3-0304 hose assembly or any hose assembly installed perthe above, with Cessna P/N 5100109-56 steel line as specified in Cessna Service Kit SK421-69.

C) When Paragraph B has been accomplished, Paragraph A is no longer applicable.

D) Any alternate means of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region.

This amendment becomes effective April 12, 1976, to all persons except those to whom it was made effective earlier by air mail letter issued March 5, 1976.