AD 76-07-12

76-07-12 BENDIX IGNITION SWITCHES: Amendment 39-2575 as amended by Amendment 39-3024. Applies to all aircraft employing magnetos and using Bendix ignition switches listed in the table below except switches identified by four digit date code (new) adjacent to the model number or a white dot (modified) on the support plate adjacent to the Bendix logo.

Bendix Switches Rotary Action, Key or Lever Actuated Switch Function Bendix (series) Part Numbers Twist-to-Start 10-357XXX, 10-126XXX Twist-to-Start/Push-to-Prime 10-357XXX, 10-126XXX Push-to-Start 10-357XXX, 10-126XXX, 10-157XXX

Compliance required as indicated:

1. For switches subject to this AD, conduct the following checks within the next 100 hours' time in service and each 100 hours thereafter to detect possible switch malfunction:

(a) Observing regular ground run-up procedures, allow the engine to reach operating temperatures and perform a normal magneto check.

(b) With the engine at normal idle, rotate the switch key or lever through the "OFF" detent to the extreme limit of its travel in the "OFF" direction.

(c) If the engine stops firing, this indicates an airworthy switch.

(d) If the engine continues to run with the switch in the extreme "OFF" direction indicating a malfunctioning switch, prior to the next flight accomplish Part III outlined in Bendix Service Bulletin No. 583, dated April 1976, for Repair and Replacement or use an alternate method approved by Chief, Engineering and Manufacturing Branch, Eastern Region.

2. The aircraft may be flown in accordance with FAR 21.197 to a place where these modifications can be accomplished.

3. The checks required by this AD may be performed by the pilot.

4. Upon submission by an operator with substantiating data, an FAA Maintenance Inspector subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA Eastern Region may adjust the compliance times specified in this AD if the request contains substantiating data to justify the increase for the operator:

(NOTE: If the engine continues to run when complying with paragraph 1 and repair or replacement cannot or will not be accomplished immediately, the magneto (primary circuit) should be grounded in accordance with Bendix Service Bulletin No. 583, dated April 1976.)

Amendment 39-2575 was effective April 14, 1976.

This amendment 39-3024 is effective August 30, 1977.