FAA Powerplant Written Practice Test

What assists in retracting the starter jaw after the motor is disengaged on a direct cranking reciprocating engine starter?

1. Hydraulic actuator

2. Return spring

3. Electromagnetic coil

4. Pneumatic system

The correct answer is: Return spring

The correct response highlights the role of the return spring in retracting the starter jaw after the motor is disengaged. In direct cranking reciprocating engine starters, the starter jaw engages with the engine's flywheel to initiate the cranking process. Once the engine reaches an operational speed and the starter is no longer needed, the starter motor is disengaged. At this point, the return spring plays a crucial role by providing the necessary force to pull the starter jaw back to its original position. This action ensures that the starter does not remain engaged with the flywheel, preventing potential damage to both the starter and the engine. The return spring allows for a reliable and efficient retraction mechanism, ensuring the starter is ready for the next starting cycle. While hydraulic actuators, electromagnetic coils, and pneumatic systems are used in various mechanical systems to control movements, they are not typically involved in the simple retracting behavior of a starter jaw in this context. The return spring’s straightforward mechanical design makes it a practical choice for this operation.