Who is accountable for checking that the altimeter system complies with regulations for instrument flight?

The accountability for ensuring that the altimeter system complies with regulations for instrument flight primarily rests with the pilot-in-command. This responsibility is critical because the pilot-in-command is tasked with the overall safety of the flight and must ensure that all equipment, including the altimeter system, is functioning properly and meets regulatory standards before takeoff.

The pilot-in-command must verify that the altimeter has been properly calibrated and that it operates accurately under the conditions of the flight. This includes checking the altimeter setting and ensuring that the aircraft is equipped with the appropriate instruments for the expected flight conditions. Given that the pilot directly operates the aircraft and is responsible for navigation and safety during the flight, this accountability is vital in maintaining instrument flight regulations.

While the owner of the aircraft, the operator, and the maintenance technician also have roles in the maintenance and operational readiness of the aircraft, the pilot-in-command is the final authority who confirms that everything required for safe operation is in order prior to flight.