14 CFR 91.123 — Compliance with ATC Clearances and Instructions
Pilots must comply with ATC clearances and instructions when operating in controlled airspace, unless an emergency requires deviation.
Regulation Text
When an ATC clearance has been obtained, no pilot in command may deviate from that clearance unless an amended clearance is obtained, an emergency exists, or the deviation is in response to a traffic alert and collision avoidance system resolution advisory. Each pilot in command who deviates from an ATC clearance or instruction shall notify ATC of that deviation as soon as possible.
Note: This is an excerpt. Refer to the full regulation in eCFR for the complete text.
Plain-English Explanation
When ATC gives you a clearance, you must follow it. The only exceptions are emergencies, TCAS resolution advisories, or getting an amended clearance. If you do deviate, tell ATC as soon as possible. Note the difference between clearances (specific authorizations) and instructions (general directions). This regulation works with 91.3 — you have emergency authority, but you must communicate. The FAA may ask for a written report within 48 hours.
Tested On These Exams
Related Regulations
14 CFR 91.3 — Responsibility and Authority of the Pilot in Command
The PIC is directly responsible for and is the final authority as to the operation of the aircraft. In an emergency, the PIC may deviate from any rule to the extent required.
§91.12914 CFR 91.129 — Operations in Class D Airspace
Requires two-way radio communication with the control tower and compliance with ATC instructions when operating in Class D airspace.
§91.13114 CFR 91.131 — Operations in Class B Airspace
Requires an explicit ATC clearance to enter Class B airspace, operative transponder with Mode C, and specific pilot certificate requirements.
Pass your FAA exam in 30 days
Pilot Exam Crash Course
This regulation will be on your exam. Get 1,000+ practice questions with instant explanations. 94% of students pass on their first attempt.
50% off first month. Cancel anytime. 2,200+ questions.
Or subscribe for full access
All Exams, All Regulations — $7.49/mo
1,000+ questions covering all FARs. Cancel after you pass.
Cancel anytime. No commitment.