Boeing's team is in Ethiopia helping the investigators. The company says it is "devoted to the quality and safety of the aircraft we design, produce and support".
Jim Hall, former chairman of America's National Transportation Safety Board, another regulator,
sees the root of the problem in the FAA's close relationship with Boeing.
Since 2001 the company has lobbied vigorously to perform more of its own safety tests.
In 2005 the FAA began to allow Boeing to do more self-certification. "It's like putting children in charge of the sweet shop," says a former Boeing adviser.
An investigation by the transportation department in 2012 found that the FAA had not done enough to "hold Boeing accountable".
It quoted FAA employees who had reported retaliation for speaking up about problems with Boeing's previous designs.
Scott Brenner, a former associate administrator at the FAA, points out that safety inspectors at the FAA's office in Seattle,
home to Boeing's main production facilities, may have worked closely with Boeing's own safety experts for decades.
A once-antagonistic relationship has grown chummier in recent years. Posters warning "don't talk to the FAA" are no longer a common sight.
It has not helped that President Donald Trump has left the top job at the FAA vacant since January 2018.
The acting administrator lacks all the powers of a permanent head, notes Mr Hall.
Financial constraints encouraged the FAA to outsource certification to planemakers.
Its budget increased by a sixth between 2002 and 2018, while American air traffic grew by 40%.
On March 19th Mr Trump named Stephen Dickson, a respected former senior executive at Delta Air Lines, to head the FAA.
By then, other regulators' confidence in the FAA had been shot.
The Ethiopian authorities have declined to give the black box to the FAA for data retrieval, sending it to France instead.
Those in Canada and Europe are re-examining decisions to approve the 737 Max based on mutual-recognition agreements with America.
Rather than trust the FAA, they may order their own tests before certifying future Boeing aircraft as airworthy.