14 CFR § 99.17 - Deviation from flight plans and ATC clearances and instructions.

---
identifier: "/us/cfr/t14/s99.17"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "14 CFR § 99.17 - Deviation from flight plans and ATC clearances and instructions."
title_number: 14
title_name: "Aeronautics and Space"
section_number: "99.17"
section_name: "Deviation from flight plans and ATC clearances and instructions."
chapter_name: "FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "F"
subchapter_name: "AIR TRAFFIC AND GENERAL OPERATING RULES"
part_number: "99"
part_name: "SECURITY CONTROL OF AIR TRAFFIC"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "49 U.S.C. 106(g), 40101, 40103, 40106, 40113, 40120, 44502, 44721."
regulatory_source: "Docket 25113, 53 FR 18217, May 20, 1988, unless otherwise noted."
cfr_part: "99"
---


# 99.17 Deviation from flight plans and ATC clearances and instructions.

(a) No pilot may deviate from the provisions of an ATC clearance or ATC instruction except in accordance with § 91.123 of this chapter.

(b) No pilot may deviate from the filed IFR flight plan when operating an aircraft in uncontrolled airspace unless that pilot notifies an appropriate aeronautical facility before deviating.

(c) No pilot may deviate from the filed DVFR flight plan unless that pilot notifies an appropriate aeronautical facility before deviating.

[69 FR 16756, Mar. 30, 2004]