AD 69-12-03

69-12-03 CESSNA: Amdt. 39-775. Applies to Models 310 (Serial Numbers 35000 thru 35546); 310A (Serial Numbers 38001 thru 38161); 310B (Serial Numbers 607; 35547, 35548, 35549, 35551 thru 35771); 310C (Serial Numbers 35550, 35772 thru 35999, 39001 thru 39031); 310D (Serial Numbers 39032 thru 39299); 310E (Serial Numbers 35912A, 310M0001 thru 310M0036); and 310F (Serial Numbers 310 0001 thru 310 0156) Airplanes.

Compliance: Required as indicated.

To prevent complete loss of engine power due to air being introduced into the fuel system should a fuel crossfeed line become chafed through by the firewall stiffener on the aft side of the aircraft firewall, unless already accomplished, perform the following:

A) Within 25 hours' time-in-service after the effective date of this airworthiness directive, remove the firewall access opening for both engines and visually inspect the fuel crossfeed lines for chafing at the firewall stiffeners. Replace chafed fuel lines with a serviceable part and install P/N 0826031-1 fuel line support bracket in accordance with Cessna Service Letter 310-66, dated June 30, 1961, or any equivalent method approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Central Region. A minimum of .50 inch clearance should be maintained between the fuel lines and the angle stiffener.

B) If P/N 0826031-1 fuel line support bracket is not available, the inspection required in Paragraph A must be repeated at intervals not to exceed 100 hours time-in-service from the date of the last inspection, until P/N 0826031-1 fuel line support bracket is installed in accordance with Cessna Service Letter 310-66, dated June 30, 1951, or any equivalent method approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Central Region. When the support bracket has been installed, the inspections required by this airworthiness directive may be discontinued. (See Note)

Note:This does not preclude continued inspections of this area as required by FAR 91.

C) Before the inspection required by Paragraph A can be accomplished on those model aircraft with Serial Numbers 35000 through 35138, a firewall inspection opening must be installed in accordance with Cessna Service Letter 310-3, dated February 10, 1956.

This amendment becomes effective June 10, 1969.