IR.V.B.K2FAA-S-ACS-8C · Nov 2023Knowledge
Pilot/controller responsibilities, communication procedures, and ATC services available...
Pilot/controller responsibilities, communication procedures, and ATC services available to pilots.
Bottom line
Unless otherwise authorized by ATC, a pilot who has two-way radio communications failure while operating under IFR must comply with the rules of 14 CFR 91.185. The pilot must notify ATC of any loss of RNAV capability, together with the proposed course of action.
Key numbers
| Number | What it means |
|---|---|
| 500 ft above airport elevation, engage lateral RNAV guidance no later than this | RNAV DP |
| 1,000 ft position confirmation at start of takeoff roll | DME/DME/IRU |
| 1,500 ft above the surface, turbine-powered or large airplanes | Class D climb |
FAA references
- 14 CFR 91.185 (IFR operations: Two-way radio communications failure.) — eCFR current as of 2026-03-05
- AC 90-100, paras. 10c, 10d — AC No: 90-100A
- 14 CFR 91.129 (Operations in Class D airspace.) — eCFR current as of 2026-03-05
- 14 CFR 91.130 (Operations in Class C airspace.) — eCFR current as of 2026-03-05
- AC 91-74, para. 6-2 — AC No: 91-74A
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