AD 79-02-01

79-02-01 ENSTROM HELICOPTERS: Amendment 39-3390. Applies to Enstrom Model F-28C and 280C helicopters certificated in all categories. Compliance required as indicated, unless previously accomplished. In order to prevent damage to the turbocharger and possible engine power loss accomplish the following:

Within 50 hours time in service after the effective date of this AD, accomplish the following:

A. Inspect the Rajay turbocharger. If the turbocharger serial number is 70484 or greater, proceed with step B. If the turbocharger serial number is less than 70484 accomplish the following:

1. Remove the turbocharger from the helicopter in accordance with the Enstrom Maintenance Manual.

2. Using a 5/32 Allen wrench, remove the six counter-sunk cap screws that secure the compressor housing to the bearing housing assembly. If necessary, gently tap the compressor housing with a plastic hammer to loosen it from the bearing housing assembly.

3. Torque the three bearing housing flange attachment screws on the turbocharger to 90 + 10 inch-pounds. "Stake" the screws in place in accordance with the sketch and notes which follow this AD.

4. Reinstall the compressor housing by placing the turbocharger on the compressor housing using a new gasket, Rajay P/N TC6-44. Secure with six cap screws and tighten evenly and alternately to 90 + 10 inch-pounds.

5. Reinstall the turbocharger in the helicopter in accordance with the Enstrom Maintenance Manual.

B. Remove the induction system air inlet filter in accordance with the Enstrom Maintenance Manual.

C. Remove the AN815-6D union which attaches the fuel nozzle air vent installation to the induction system air inlet filter container. Save the AN924-6D nut which was holding the union in place, for reinstallation, in accordance with step D.

D. Install an AN832-6D union, in place of the AN815-6D union, so that the AN924-6D nut is outside of the filter container.

E. Attach the fuelnozzle air vent line to the AN832-6D union.

F. Replace the air filter in accordance with the Enstrom Maintenance Manual.

Equivalent methods of compliance may be approved by the Chief, Engineering and Manufacturing Branch, FAA Great Lakes Region.

This amendment becomes effective January 17, 1979.