Final answer:
The location of the APU gearbox oil and APU generator adapter oil dipsticks varies by aircraft model and should be verified by consulting the aircraft's maintenance manual. Generally, dipsticks are accessible in or around the APU enclosure.
Step-by-step explanation:
The dipsticks for the Auxiliary Power Unit (APU) gearbox oil and the APU generator adapter oil are critical components for maintaining proper lubrication levels, which ensure the effective and reliable operation of the APU system. Without sufficient oil levels, the APU could suffer from increased wear and potential failure. Checking the oil levels is an essential part of routine maintenance for the APU.
For the specific location of the dipsticks:
Option (A) suggests they are behind the service door of the APU enclosure.
Option (B) indicates that they are on top of the APU gearbox and the APU generator adapter, respectively.
Option (C) places them on the side of the APU gearbox and the APU generator adapter, respectively.
Option (D) locates them inside the APU enclosure, near the oil reservoirs.
Often, the design and configuration of APU systems can vary by aircraft model, therefore it is best to consult the official maintenance manual for the aircraft in question to determine the exact location of these dipsticks. However, generally, the dipsticks can commonly be found in or around the APU enclosure for ease of maintenance.