Title: Describe altimeter settings and setting procedures and the importance of accurate altimeters.
Course: Aircraft Pilot Training I (20053-I) > Section: Interpreting Flight Instruments

Description should include the following:

- Most altimeters are equipped with a barometric pressure setting window (or Kollsman window) providing a means to adjust the altimeter. A knob is located at the bottom of the instrument for this adjustment.
- To adjust the altimeter for variation in atmospheric pressure, the pressure scale in the altimeter setting window, which is calibrated in inches of mercury ("Hg) and/or millibars (mb), is adjusted to match the given altimeter setting.
- Altimeter setting is defined as station pressure reduced to sea level, but an altimeter setting is accurate only in the vicinity of the reporting station.
- The pilot must be sure that the aircraft is flying high enough to clear the highest terrain or obstruction along the intended route.
- It is especially important to have accurate altitude information when visibility is restricted.

PLT166 and PLT167

Process/Skill Questions:

- How are altimeters set?
- Why is it important to have an accurate altimeter?