Regulation Text
(a) No person may operate an airplane, or helicopter, in controlled airspace under IFR unless—
(1) Within the preceding 24 calendar months, each static pressure system, each altimeter instrument, and each automatic pressure altitude reporting system has been tested and inspected and found to comply with appendices E and F of part 43 of this chapter;
(2) Except for the use of system drain and alternate static pressure valves, following any opening and closing of the static pressure system, that system has been tested and inspected and found to comply with paragraph (a), appendix E, of part 43 of this chapter; and
(3) Following installation or maintenance on the automatic pressure altitude reporting system of the ATC transponder where data correspondence error could be introduced, the integrated system has been tested, inspected, and found to comply with paragraph (c), appendix E, of part 43 of this chapter.
(b) The tests required by paragraph (a) of this section must be conducted by—
(1) The manufacturer of the airplane, or helicopter, on which the tests and inspections are to be performed;
(2) A certificated repair station properly equipped to perform those functions and holding—
(i) An instrument rating, Class I;
(ii) A limited instrument rating appropriate to the make and model of appliance to be tested;
(iii) A limited rating appropriate to the test to be performed;
(iv) An airframe rating appropriate to the airplane, or helicopter, to be tested; or
(3) A certificated mechanic with an airframe rating (static pressure system tests and inspections only).
(c) Altimeter and altitude reporting equipment approved under Technical Standard Orders are considered to be tested and inspected as of the date of their manufacture.
(d) No person may operate an airplane, or helicopter, in controlled airspace under IFR at an altitude above the maximum altitude at which all altimeters and the automatic altitude reporting system of that airplane, or helicopter, have been tested.
[Docket 18334, 54 FR 34308, Aug. 18, 1989, as amended by Amdt. 91-269, 66 FR 41116, Aug. 6, 2001; 72 FR 7739, Feb. 20, 2007]
Research Notes
Section 91.411 — Altimeter system and altitude reporting equipment tests and inspections — establishes the 24-month inspection requirement for IFR altimeter and static systems.
The 24-calendar-month rule: No person may operate an aircraft IFR (or in controlled airspace requiring transponder altitude reporting) UNLESS within the preceding 24 calendar months, the altimeter system and altitude reporting equipment have been tested and inspected per:
- (a) Part 43 Appendix E (altimeter system test and inspection); AND
- (b) Part 43 Appendix F (altitude reporting equipment - Mode C).
Who performs the test: A certificated repair station appropriately rated to perform the test, OR a manufacturer of the equipment, OR a mechanic with airframe rating where authorized.
What gets tested: Altimeter accuracy at various altitudes, static system leakage rate, altitude reporting equipment (Mode C) accuracy. The altimeter is verified to read within tolerance at multiple test altitudes (typically -1,000, 0, +5,000, +10,000, +20,000, +25,000 feet depending on aircraft certification).
The 'IFR-required' confusion: § 91.411 says it applies to operations IFR OR in controlled airspace requiring altitude reporting. Since most controlled airspace requires Mode C (Class A, B, C, Mode C veil, above 10,000 MSL), most aircraft need § 91.411 currency to operate in those airspace classes — even VFR.
Reference: Part 43 Appendix E (Altimeter test) and Part 43 Appendix F (Altitude reporting test).
Amendment History
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