Flight Crewmembers at Stations

Section 91.105 requires each flight crewmember to be at their station during takeoff, landing, and while en route — with the seat belt fastened. It also requires the shoulder harness to be fastened during takeoff and landing if installed.

Who is a flight crewmember: A flight crewmember is a person assigned to perform duty in an aircraft during flight time. In a Cessna 172 with just a CFI and a student, both are flight crewmembers (the student is the pilot flying, the CFI is the PIC). In a Pilatus PC-12 with a single pilot, that pilot is the only flight crewmember.

'At their station' — the bathroom break question: The reg permits a crewmember to leave their station temporarily during cruise for physiological needs or to perform necessary duties (an autopilot cross-check, EFB resync, etc.). The FAA's interpretation is that the crewmember must return as soon as practicable. Leaving the cockpit during takeoff or landing — even briefly — is not allowed under any reading of the reg.

Shoulder harness rule: Required during takeoff and landing IF the aircraft has shoulder harnesses installed at the crew station. The FAA does NOT require operators to install shoulder harnesses retroactively, but if they're installed, they must be worn during takeoff and landing. Many 1970s-era GA aircraft lack factory shoulder harnesses; aftermarket installations make the harness required by § 91.105.

Seat belt at all times en route: The seat belt requirement is broader than the harness — it must be fastened during takeoff, landing, AND while en route. A crewmember can release the belt for short breaks but must keep it fastened during routine operation.

Reference: FAA-H-8083-25 (PHAK) Chapter 2 on aircraft systems including restraint systems. NTSB safety recommendations on shoulder harness use are clear: shoulder harnesses dramatically reduce occupant injury in survivable accidents.