Altimeter system and altitude reporting equipment tests and inspections

To fly IFR in controlled airspace, your static and altitude-reporting systems must have been recently tested. § 91.411 requires that within the preceding 24 calendar months:

• each static pressure system, each altimeter, and each automatic pressure-altitude reporting system has been tested and found to comply with Part 43 appendices E and F;
• after any opening/closing of the static system (other than normal drain/alternate-static use), that system has been re-tested per appendix E; and
• after installation or maintenance on the altitude-reporting system where a correspondence error could be introduced, the integrated system has been tested per appendix E.

These tests must be done by an appropriately rated facility or person — the aircraft manufacturer, a properly rated certificated repair station, or (for the static-system portion only) a certificated mechanic with an airframe rating.

You also may not operate IFR above the maximum altitude at which the altimeters and altitude-reporting system were tested. This is the companion to the § 91.413 transponder test — together they're the "pitot-static and transponder" checks.

Summary: For IFR in controlled airspace, the static system, altimeters, and altitude-reporting system must have been tested within the preceding 24 calendar months per Part 43 appendices E/F (plus after static-system work), done by the manufacturer, a rated repair station, or — for static only — an airframe-rated mechanic; you can't fly IFR above the tested altitude.