What does disarm doors mean? Air NZ pilot explains arming, and disarming

An Air New Zealand pilot has revealed why crew always open aircraft doors a specific way after landing at an airport.

Once a plane lands and pulls up to the gate, most travellers are likely focused on gathering their belongings and preparing to disembark.

If you pay attention to the crew and aircraft doors you’ll notice the crew always open the doors the exact same way, according to Captain David Morgan, the chief pilot and chief operational integrity and safety officer at Air New Zealand.

Crew on board arm and disarm a door during the journey but it will always be groundcrew who open the aircraft door when it arrives at an airport.

“You may notice that we always open our doors from the outside,” Captain Morgan said during a tour of the airline’s new Cabin Emergency Evacuation Trainer (CEET) device.

Captain David Morgan, Air New Zealand chief operational integrity and safety officer. Photo / Michael Craig

The reason for doing this, Morgan said, is to avoid a “very expensive” and dangerous mistake; deploying the slide, which happens if a door has mistakenly not been disarmed.

“If a door hasn’t been disarmed, then what will happen is that the action of opening the door from the outside actually disarms the slide,” he explained.

“The last thing you want is a slide deploying into the air bridge,” he added.

What does arming and disarming a door mean?

When a door is disarmed, the lever will be in the green position and it’s “just a door” Captain Morgan said.

“When you put it in the armed position, by flicking that lever down, you actually connect the raft, which is in the bustle,” he said.

A replica of an "armed" door and bustle, which holds the emergency slide, during an Air NZ training session. Photo / Air New Zealand

“You know how difficult it is to pack a suitcase?” he jokes, pointing to the bustle built into the bottom of a mock-up door, then at a gigantic fully-inflated slide set up beside it.

When a plane is ready to disembark, the doors should all be disarmed, so the slide does not deploy when they open. However, to be safe, the crew still open it from the outside, to ensure the slide is always detached and never deploys.

Once you begin opening the door, there’s no closing it if you realise it’s armed, Captain Morgan said.

“Inside the hinge here, there’s a whole lot of machinery that actually forces the door out. So it goes out automatically and once it’s on its way, you can’t stop it,” he said.