Final answer:
The dipsticks for the APU gearbox and APU generator adapter oils are located in the APU housing, typically at the tail section of an aircraft, and they are crucial for checking oil levels as part of maintenance.
Step-by-step explanation:
The dipsticks for checking the oil levels of the Auxiliary Power Unit (APU) gearbox and the APU generator adapter are located within the APU housing, which is usually situated in the tail section of the aircraft. For many aircraft models, maintenance technicians access the APU compartment from an exterior panel and use the dipsticks to measure oil levels as part of routine checks. Verifying the APU gearbox oil level and APU generator adapter oil level is crucial for the reliable operation and longevity of the APU system.