The chair of the US House Committee on Transportation and Infrastructure has formally invited Boeing chief executive Dennis Muilenburg to testify before the full committee on 30 October.

Democratic congressman Peter DeFazio’s invitation to Muilenburg and chief engineer of Boeing’s Commercial Airplanes division John Hamilton comes less than a week after top democrats on the committee had asked Boeing to make employees available for interviews regarding the design, development and certification of Boeing 737 Max aircraft.

Boeing says in a statement that it received the committee’s invitation and is reviewing it now.

“We will continue to cooperate with Congress and regulatory authorities as we focus on safely returning the Max to service,” Boeing says.

US lawmakers have already questioned witnesses about Max aircraft during numerous hearings since the worldwide grounding of those aircraft in March following the deaths of 346 passengers and crew in two crashes.

Witnesses included trade association representatives, members of pilots’ unions, officials from federal agencies and relatives of crash victims. So far, no one from Boeing has been interviewed during these hearings in the House or Senate.

Investigations into the crashes of Ethiopian Airlines flight 302 and Lion Air flight 610 remain ongoing, but evidence indicates that automated flight control software created by Boeing automatically trimmed the aircraft into dives after being triggered by problems with an angle-of-attack indicator. The software was designed specifically for Max aircraft to make them fly like earlier-generation 737NG aircraft.

Boeing is coordinating with the FAA on software modifications to gain approval from the regulator to return Max aircraft to service.