BOEING CEO Dennis Muilenburg did not provide complete testimony last week on the 747 Max in the opinion of congressmen of the US House Transportation & Infrastructure Committee and left "a lot of unanswered questions". Committee chairman Peter DeFazio and leader of its aviation sub-panel Rick Larsen said in a letter to other lawmakers that the investigation into the troubled aircraft has a "long way to go to get the answers everyone deserves", reported Bloomberg. "Mr Muilenburg's answers to our questions were consistent with a culture of concealment and opaqueness and reflected the immense pressure exerted on Boeing employees during the development and production of the 737 Max," the lawmakers said in the letter. The letter summarised testimony and documents revealed by the committee, such as a 2015 warning by a Boeing engineer that the system later involved in two fatal crashes wasn't sufficiently checked. The committee also raised concerns about whether the design met the company's own criteria, and if pilots could be expected to handle the emergencies that occurred in the aircraft.