The US Federal Aviation Administration (FAA) has revealed plans to issue a notice of proposed rulemaking (NPRM) for Boeing 737 MAX Airworthiness Directive (AD).

Boeing 737 MAX aircraft has been grounded since March 2019 following two fatal crashes in Indonesia and Ethiopia that killed 346 people.

In a statement, FAA said: “In keeping with our commitment to remain transparent, the NPRM will provide 45 days for the public to comment on proposed design changes and crew procedures to mitigate the safety issues identified during the investigations that followed the Lion Air and Ethiopian Airlines accidents.”

The agency is currently continuing with the certification process and the 737 MAX Technical Advisory Board (TAB) is providing review and consultation.

It is also focused on carrying out the remaining tasks such as publishing the final Flight Standardization Board (FSB) report.

The FAA’s FSB final planning and the Joint Operations Evaluation Board (JOEB) review of proposed training for flight crews is currently underway.

Boeing has previously said it expects to resume deliveries before 30 September.

Boeing spokesman Gordon Johndroe was quoted by Reuters as saying: “Boeing is working closely with the FAA and other international regulators to meet their expectations as we work to safely return the 737 MAX to service.”

Last month, FAA head Stephen Dickson confirmed that Boeing 737 MAX aircraft will return only after ‘a comprehensive and rigorous review process’.

Earlier this month FAA and Boeing completed the three days of certification test flights on the 737 MAX’s automated flight control system.