Definition
A Federal Aviation Regulation that establishes the 'sterile cockpit rule' for air carriers operating under Part 121. It prohibits flight crewmembers from performing any non-essential duties or activities, and from engaging in non-essential conversation, during critical phases of flight — defined as taxi, takeoff, landing, and all other flight operations conducted below 10,000 feet, except cruise flight.
Plain English
This is the rule that says airline pilots must keep their full attention on flying whenever the airplane is taxiing, taking off, landing, or operating below 10,000 feet. No chatting about non-flying topics, no eating meals, no reading the newspaper — just flying the airplane.
Context Anchor
Seen in runway incursion, taxi, and crew distraction discussions, especially when explaining why nonessential cockpit activity must stop during taxi and other critical phases of flight.
Derivation
CFR' stands for Code of Federal Regulations — the official collection of U.S. federal rules. 'Part 121' is the section governing scheduled air carriers (airlines). The section number '§ 121.542' identifies this specific rule within that part. The informal name 'sterile cockpit rule' came from the idea of keeping the cockpit free of distractions, like a sterile surgical field.
Why Pilots Care
Following this regulation reduces distraction during the most error-prone phases of flight and helps prevent runway incursions and other incidents.
Intuition Check
Do not treat this as just a suggestion about good cockpit manners. It is a specific federal rule for Part 121 operations, and its safety idea is widely applied in pilot training: during critical phases, only safety-related tasks belong in the cockpit.
Example Sentence 1
During taxi out, the first officer remembered the sterile cockpit rule under 14 CFR 121.542 and held off on the conversation until they reached cruise altitude.
Example Sentence 2
The captain cited 14 CFR Part 121 § 121.542 when asking the first officer to hold nonessential conversation until after landing.