Canadian airlines have been ordered to maintain two crew in the cockpit at all times, effective immediately, federal Transport Minister Lisa Raitt announced today.

"Currently, there is not the requirement to have two members in the [cockpit]," Raitt told reporters. "After this order, there will be a requirement to have two members."

"It could be a flight attendant. It could be a customer service person," she said. "But they have to be members of the cabin crew."

The move followed revelations that a Germanwings co-pilot apparently caused the crash of Flight 4U9525 after preventing the pilot from returning to the cockpit. 

Air Canada and WestJet both said they were changing their policy to ensure that there are always two people in the cockpit on their flights. Air Transat, which also agreed to the two-person rule, admitted it didn't have a specific policy in place until now.

"Following initial reports on the Germanwings accident, we are implementing without delay a policy change to ensure that all flights have two people in the cockpit at all times," Air Canada said in a statement to CBC News. 

Porter Airlines said it has always had a policy requiring "at least two crew in the flight deck at all times during flight."

'Rule of 2'

Many U.S. airlines already have a "rule of two" requiring that if one pilot leaves the cockpit another crew member, such as a flight attendant, must be in the cockpit as a replacement. But this is not an FAA requirement.

Lufthansa, owner of the downed Germanwings plane, does not have such a rule, nor is it required to follow such a practice.

FRANCE-CRASH/COPILOT

A person moves the switch of the cockpit door locking system inside a flight simulator of an Airbus A320, like the one that crashed in the French Alps. (Leonhard Foeger/Reuters)

Dominic Fouda, a spokesman for the European Aviation Safety Agency, told CBC News that it does not require two people in the cockpit at all times.

But as a matter of airline policy, several European airlines, including Finnair, do require two people to be in the cockpit when a flight is in the air. Norwegian Air Shuttle, Europe's third largest budget airline, announced Thursday it would also adopt a rule requiring two crew members to be present in the cockpit.

Norwegian spokeswoman Charlotte Holmbergh-Jacobsson said the new rules will be in place "as soon as possible" on all commercial flights globally.

Security protocols

As soon as it was learned that one of the pilots appeared to have been deliberately locked out of the cockpit of Germanwings Flight 4U9525 before it crashed, attention quickly turned to the security protocols relating to the cockpit door that separates the flight deck from the rest of the plane.   

Those protocols have steadily evolved over the years, but it was one big event almost 15 years ago that changed everything – the Sept. 11 attacks.

Within weeks, the U.S. Federal Aviation Administration (FAA) had mandated new standards to strengthen cockpit doors to protect pilots from intrusion and small arms fire, even grenades. Most airlines, including Germanwings, reinforced their cockpit doors.

But fortifying those doors was just one part of the security upgrade. The FAA also required that cockpit doors remain locked during flight.

"The door will be designed to prevent passengers from opening it without the pilot’s permission," a 2002 FAA release said. "An internal locking device will be designed so that it can only be unlocked from inside the cockpit."

'The most plausible, realistic interpretation … is that the co-pilot … refused to open the door of the cabin to the captain.' — Brice Robin, French prosecutor

That's where things appear to have gone terribly wrong on board the Germanwings flight.

Airbus cockpit doors lock by default when they are closed. An Airbus training video shows that the A320 cockpit has procedural safeguards in place in the event that one pilot inside the cockpit becomes incapacitated while the other is outside, or if both pilots inside are incapacitated.

When one of the pilots leaves the cockpit, he or she can get back in by communicating by intercom or buzzer with the person inside. The inside person can peer through a peephole or use a camera feed to decide whether to allow that person to enter. If there is no answer to a request for access, the person outside can enter an emergency keycode to get access. If there is still no response, the door opens automatically 30 seconds later.

"There was always the opportunity to open the door from the inside and if that is not possible, then you can open the door from the outside via a code," German Transport Minister Alexander Dobrindt confirmed Thursday.

Lockdown mode

But the Airbus video says the person on the inside of the cockpit has the ability to specifically deny the emergency access request by pressing an override switch that causes the door to go into lockdown mode for five minutes. Lufthansa's CEO acknowledged that may be what the co-pilot did in this case. 

Lisa Raitt Transport Minister

The circumstances of the crash of the Germanwings jet this week prompted Transport Minister Lisa Raitt to implement new rules for Canadian airlines. (Sean Kilpatrick/Canadian Press)

"There is another code you can actually operate which will also lead to a bell ringing, and if nobody actually reacts, the door will open electrically and automatically, and this can be impeded by those in the cockpit by actually pressing a lever which says 'lock' and the doors will be closed for five minutes," Lufthansa CEO Carsten Spohr told a news conference.

"It seems to be true that the colleague who remained in the cockpit, the co-pilot, denied him access back into the cockpit in order to start the fatal descent in the French Alps," he said.

"The most plausible, realistic interpretation as far as we are concerned is that the co-pilot … refused to open the door of the cabin to the captain, and pressed the button which caused the aircraft to lose altitude," French prosecutor Brice Robin said.

With files from The Associated Press