The US Federal Aviation Administration (FAA) head Stephen Dickson has confirmed that Boeing 737 MAX aircraft will return only after ‘a comprehensive and rigorous review process’.

Boeing 737 MAX aircraft has been grounded since March 2019 following two deadly crashes in Indonesia and Ethiopia.

Dickson testified before the US Senate Committee on Commerce, Science, and Transportation that safety is the driving factor its thorough process.

The agency revealed that the aircraft will return to service after it signs off on all technical reviews of Boeing’s proposed safety enhancements.

Dickson said: “As we have stated many times in the past, safety is the driving consideration in this process. This process is not guided by a calendar or schedule.

“I have directed FAA employees to take the time needed to do that work.”

Prior to service, there will be a certification flight test and completion of work by the Joint Operations Evaluation Board (JOEB).

The board consists of FAA and international partners from Canada, Europe, and Brazil. It will evaluate the pilot training requirements.

The FAA’s Flight Standardisation Board for the Boeing 737 will also release a report in response to JOEB findings.

Additionally, the agency and multi-agency Technical Advisory Board (TAB), a board comprising of FAA chief scientists and experts from the US Air Force, Nasa and Volpe National Transportation Systems Centre, will review the full final design documentation.

Last month, Boeing restarted 737 MAX productions at its facility in Renton, Washington, US.