What tools are necessary to check the oil level in the air cycle machine?

To check the oil level in the air cycle machine, the correct tools are a mirror and a flashlight. The mirror is vital because it allows the technician to see into areas that are otherwise difficult to access or view directly, especially in cramped spaces like those found in aircraft engines or machinery. The flashlight is equally important as it provides the necessary illumination to clearly see the oil level indicator or mark within the air cycle machine.

Using a mirror enables the technician to avoid awkward positioning and provides a clearer view of the oil level without needing to disassemble components or put oneself in a potentially hazardous situation. The flashlight enhances visibility, making it easier to assess whether the oil level is within the acceptable range.

In contrast, the other tool combinations, while perhaps useful in different contexts, do not specifically meet the requirements for checking the oil level in this scenario.