In giving clearance for the return to commercial flights, the US Federal Aviation Administration (FAA) has told Boeing several new safety measures must be taken before putting the aircraft back into the skies.

The FAA said these included “installing new flight control computer software”, revising flight crew procedures and “performing an operational readiness flight”.

Speaking on CNBC, FAA administrator Steve Dickson said: “I can tell you that I am 100% confident in the actions that we have taken, the design changes that have been put in place with the 737 Max, and I would put my own family on it.

“The work that we have done with the design changes and the training changes that will be made to the operators and the training that the pilots will be undergoing makes it impossible for the airplanes to have the same kind of accident that unfortunately killed 346 people."

The Max was grounded following accidents in October 2018 and March 2019 involving Indonesia’s Lion Air and Ethiopian Airlines. Both happened when software designed to keep the aircraft level instead led to it nose-diving uncontrollably.

"We will never forget the lives lost in the two tragic accidents that led to the decision to suspend operations," said David Calhoun, Boeing chief executive.

"These events and the lessons we have learned as a result have reshaped our company and further focused our attention on our core values of safety, quality and integrity."

In a separate notice, the FAA also outlined significant retraining of pilots needed before they are permitted to operate the aircraft again.

Tui Airways, Norwegian and Ryanair are among 737 Max operators, with British Airways parent company IAG having placed a big order for the aircraft while it was grounded.