Airline passengers often notice cockpit doors ajar as they board, with pilots and crew visible preparing for departure.
While it may raise questions about aviation security, this scene is routine and rooted in regulation.
The rules governing cockpit access differ depending on whether the aircraft is parked with the engines off, or if an engine has been started.
Why cockpit doors are open during boarding
Since the September 11 attacks, global aviation has adopted reinforced cockpit doors, mandatory locking systems and clearly defined access procedures.
These measures, however, only apply once the aircraft is capable of moving under its own power.
While still at the gate, the flight deck operates as a hub for pilots, cabin crew, engineers and ground staff to exchange information, finalise flight plans and conduct pre-departure checks – tasks that require the door to remain open.
Regulations such as those set by the Federal Aviation Administration (FAA) in the United States and the European Union Aviation Safety Agency (EASA) in Europe only require cockpit doors to be locked once the aircraft is preparing for pushback and taxi, not while the aircraft is at the gate.
EASA’s rules state that the pilots can only start the engines after the closing and locking of the flight deck door.
Pilots often need to coordinate with maintenance staff, receive last-minute operational updates, or handle paperwork relating to loading and dangerous goods.
In addition, cabin crew regularly enter the cockpit during boarding to check equipment, brief with the pilots, or update them on catering or passenger requirements.
An open cockpit door facilitates this seamless exchange and contributes to improved CRM (Crew Resource Management) – an essential tenet of airline safety.
From a passenger perspective, the sight of an open cockpit door can sometimes be reassuring. It offers a glimpse into the technical environment where the pilots work, and for children, being invited to look inside before or after the flight can be an unforgettable part of flying.
However, access is still strictly controlled: passengers cannot simply walk in, and crew are required to remain vigilant.
The rules about cockpit doors explained
Modern airliners are fitted with reinforced cockpit doors that meet strict international safety and security requirements.
These standards originate from the International Civil Aviation Organisation (ICAO) and are incorporated into regional regulations, which apply to all commercial aircraft above a certain weight threshold.
The rules demand that the door can be locked or unlocked from either pilot’s position on the flight deck, creating a controlled barrier against unauthorised entry.
Carriers are required to enforce detailed operating protocols. These cover how and when the cockpit may be accessed, both under normal circumstances and during emergencies.
Most modern aircraft use CCTV linked to a screen in the cockpit, allowing pilots to see who is requesting access.
Where aircraft are equipped only with a viewing port, an additional safeguard is mandated: whenever one pilot leaves the cockpit, another crew member must step in.
This ensures that the remaining pilot can continue flying without distraction while the door remains supervised.
The FAA stipulates that if an aircraft is fitted with a lockable cockpit door and is carrying passengers, the pilot in command is responsible for keeping that door closed and secured whenever the aircraft is in operation.
The only exceptions are specific circumstances outlined elsewhere in the regulations, but the baseline requirement is that the barrier between the flight deck and the cabin must remain locked from engine start until arrival at the gate.
A second cockpit door is coming, but not yet
The FAA has postponed by one year a regulation requiring newly delivered US passenger aircraft to be equipped with a secondary flight deck barrier.
The added layer of protection against cockpit intrusions was originally set to take effect on 25 August, but the rule will now be delayed until 2026.
Secondary barriers provide continuous protection for the flight deck, even when the cockpit door is open during flight. They are lightweight, retractable gates that stay in place when the primary flight deck door is open.
The decision to pause the rollout follows requests from Airlines for America, a trade group representing major carriers including American Airlines, United Airlines, and Delta Air Lines, which argued that a two-year delay was necessary.
The group cited the FAA’s failure to certify any secondary barrier design or approve related manuals, procedures, or training programmes as reasons for the requested extension.
