Definition
An action taken by a pilot in command during an in-flight emergency that does not comply with a specific Federal Aviation Regulation, permitted under 14 CFR 91.3(b) to the extent required to meet that emergency. If the deviation results from an ATC clearance or instruction issued during an emergency, or if requested by ATC, the pilot must submit a written report to the FAA upon request.
Plain English
When you are facing an emergency in flight, the rules allow you to break a regulation if doing so is necessary to handle the emergency safely. You may have to explain your actions in writing afterward if asked.
Context Anchor
Seen in emergency procedures and legal responsibility discussions, especially when describing what authority the pilot in command has during an in-flight emergency.
Derivation
"Deviation" comes from the Latin deviare, meaning "to turn off the road." Here it means turning off the normal regulatory path — only when an emergency requires it.
Why Pilots Care
Recognizes that pilots have legal authority to deviate when safety demands it, while still requiring post-flight justification and reporting in many cases.
Grounding Statement
If following the normal rule would make the emergency worse, the pilot may take the safer action and explain it later if required.
Intuition Check
Do not read this as permission to ignore rules whenever they are inconvenient. In aviation, deviations from regulations must be justified by a real need, such as an emergency, and limited to what the situation requires.
Example Sentence 1
After the engine failed, the pilot exercised emergency authority and accepted deviations from regulations to land on the closest suitable surface.
Example Sentence 2
After the flight the pilot documented the deviations from regulations caused by the sudden electrical failure.