AD 73-06-02

73-06-02 AERO COMMANDER: Amdt. 39-1606. Applies to all Models 500, 500A, 500B, 500U, 520, 560, 560A, 560E, 560F, 680, 680E, 680F, 680F(P), 680FL, 680FL(P) and 720 series airplanes certificated in all categories.

Compliance required within the next 200 hours' time in service after the effective date of this AD, unless already accomplished.

To prevent siphoning of fuel from the fuel tanks and thereby contribute to fuel exhaustion with resultant stoppage of both engines, accomplish the following:

a. On Models 520 and 560, serial numbers 1 through 230, replace the standard fuel cap assemblies with non-siphoning fuel cap assemblies, Aero Commander Kit No. 87A-1.

b. On the following models, replace the standard fuel cap assemblies with non- siphoning fuel cap assemblies, Aero Commander Kit No. 87A-2 (optional fuel caps already installed by use of Aero Commander Kit No. 87 are acceptable):

(1) Models 500, 500A, 500B, 500U, 560A, 560E, 560F, 680, 680E, 680F, 680F(P), 680FL(P) and 720, serial numbers 231 through 1854.

(2) Model 680FL, serial numbers 1261 through 1738.

c. The compliance time for this AD may be adjusted up to a maximum of 50 hours to coincide with the aircraft's annual or 100 hour scheduled inspection.

Aero Commander Custom Kit No. 87A contains the hardware and instructions necessary to accomplish this modification. Equivalent replacement parts approved by the Chief, Engineering and Manufacturing Branch, Flight Standards Division, Southwest Region, Federal Aviation Administration, Fort Worth, Texas, may be used.

This amendment becomes effective March 19, 1973.