Engine: Motor Plants and Auxiliary Boilers

1. A The lower pinion fails to retract, which in turn does not allow the upper pinion to retract. Because retraction of both pinions is required to supply air to the air-start motors, the engine does not start.
2. B The upper pinion fails to retract, which in turn does not allow the lower pinion to retract. Because retraction of both pinions is required to supply air to the air-start motors, the engine does not start.
3. C The lower pinion fails to engage, which in turn does not allow the upper pinion to engage. Because engagement of both pinions is required to supply air to the air-start motors, the engine does not start.
4. D The upper pinion fails to engage, which in turn does not allow the lower pinion to engage. Because engagement of both pinions is required to supply air to the air-start motors, the engine does not start.

Tip: press A-D to answer