Definition
A required inspection and check of an aircraft's altimeter system and static pressure system to confirm it meets the accuracy and integrity standards specified in 14 CFR Part 91.411. For IFR flight in controlled airspace, this test must have been performed and recorded within the preceding 24 calendar months.
Plain English
A check, done by a qualified shop, that proves the altimeter is reading altitude correctly and that the system feeding it pressure is sealed and accurate. It must be current within the last 24 calendar months for IFR flight.
Context Anchor
Seen during IFR preflight when the pilot checks aircraft records and required inspections before departure.
Derivation
Altimeter comes from altitude, meaning height, and meter, meaning a measuring device. That helps because an altimeter is the instrument that measures the aircraft’s height, and the test confirms that measurement is trustworthy.
Why Pilots Care
Accurate altitude information is required for terrain clearance, obstacle avoidance, and compliance with ATC altitude assignments.
Intuition Check
Do not read this as a quick glance at the altimeter before takeoff. In this context, an altimeter test means a formal inspection and accuracy check recorded in the aircraft’s maintenance records.
Example Sentence 1
Before departing on the IFR cross-country, she checked the maintenance logbook and confirmed the altimeter test was signed off eight months ago.
Example Sentence 2
During the IFR preflight the crew cross-checked both altimeters after completing the altimeter test.