What is the first step to determine the altimeter using the Aneriod Altimeter Setting Indicator (ASI)?

The first step to determine the altimeter using the Aneroid Altimeter Setting Indicator (ASI) involves tapping the face of the instrument. This action is essential as it helps to ensure that the instrument is functioning properly and that the needle is positioned correctly at zero altimeter setting. Tapping can dislodge any potential sticking mechanisms within the altimeter, allowing for a more accurate reading.

While calibration of the instrument is crucial for accuracy and adjusting the setting manually is necessary after obtaining the correct barometric pressure reference, these steps follow the initial tapping action to ensure that the altimeter is responding as expected. Inspecting the indicator for damage is also important for overall maintenance but does not directly address the immediate need to ensure proper function for a reading. Thus, tapping the ASI is indeed the right initial approach in this context.