A number of airlines have promptly changed their rules on how many crew members should be present in the cockpit at all times - after it emerged that the co-pilot of the doomed Germanwings plane deliberately locked out his captain before crashing the aircraft.
Andreas Lubitz, 27, apparently crashed the Airbus A320 in the French Alps on Tuesday while the captain was locked out of the flight deck, killing 150 people.
Airlines including Easyjet, Virgin Atlantic, Monarch, Norwegian Air Shuttle, Air Canada have already revised their flight deck policy in the wake of the tragedy, meaning two crew members will have to be in the cockpit at all times, in line with US rules.
After terrorist attacks in 2001, American aviation authorities introduced new rules that make it mandatory for a cabin crew member to enter the cockpit if the captain or first officer leave for any reason. But the rule was not enforced in Europe.
Virgin Atlantic has already changed their policy, with a spokesman telling the Daily Telegraph: "We always ensure we have the highest safety standards and, while it is our common practice to have two members of our crew in the flight deck at all times, in light of recent events we are now in the process of formalising this to be policy."
And an Easyjet spokesperson said: "EasyJet can confirm that, with immediate effect it will change its procedure, which will mean that two crew members will be in the cockpit at all times. This decision has been taken in consultation with the Civil Aviation Authority.
"The safety and security and of its passengers and crew is the airline's highest priority."
The Civil Aviation Authority has now asked all UK carriers to review their policy.
Speaking to the Guardian, a spokesman said: "Following the details that have emerged regarding the tragic Germanwings incident, we are coordinating closely with colleagues at the European Aviation Safety Agency (EASA) and have contacted all UK operators to require them to review all relevant procedures."