Daniel Elwell testified in front of the house aviation subcommittee about the problems saying his agency didn't have enough evidence to ground the jet a year ago.
Another report on Tuesday said the FAA did not independently evaluate the safety of a Boeing 737 MAX system implicated in the two deadly crashes, deferring to Boeing on key judgments.
"I'm concerned that it took a year, and we're looking into that, and we're going to fix that", Elwell, a former airline pilot, told Rep. Peter DeFazio, D-Ore., during a hearing before the House Aviation Subcommittee.
"I've never looked at an accident where there weren't three or four or five links of the chain, any one of which, if it hadn't gone wrong, the plane would have survived", he said.
A Boeing 737 MAX 8 sits outside the hangar during a media tour of the Boeing 737 MAX at the Boeing plant in Renton, Washington December 8, 2015.
Some airline pilots have complained about not having enough information about the MCAS system and its potential pitfalls, and in response to questioning, Elwell acknowledged that "the MCAS should have been more adequately explained in the ops manual and the flight manual, absolutely".
"It bothers me that we continue to tear down our system based on what has happened in two other countries, " said Representative Sam Graves, a Republican of Missouri.
"The FAA needs to fix its credibility problem", Larsen said. In total, 346 people died in the two crashes.
Elwell said he first learned about a late-November American Airlines pilots meeting with a pilot from news reports.
DeFazio said the committee is still in the early stages of its review of how the plane was certified by FAA.
"The only thing that is going to stop this is the public", Milleron said in an interview.
Elwell said the agency expects to get the software upgrade and training update from Boeing in the "next week or so".
"We flat out deserve to know what is on our airplanes", one pilot says on the recording.
Under the FAA's delegation system, companies such as Boeing can appoint people to work as the FAA's "authorized representatives" with the ability to issue certifications. The investigation results so far, however, have not suggested Boeing intentionally misled the FAA.
Asked by Rep. Sharice Davids, a Democrat from Kansas, whether the FAA moved too quickly to certify the plane for flight, Elwell outlined the five-year process that ended in 2017, including almost 300 test flights, and said it wasn't out of the ordinary.
The Allied Pilots Association, which represents American Airlines pilots, tweeted a Dallas Morning News article on the meeting. A new feature on the plane called MCAS played a role in the crashes in Indonesia and Ethiopia.
Boeing said last week it only discovered once deliveries of the 737 MAX had begun in 2017 that the so-called AOA Disagree alert was optional instead of standard as it had intended, but added that was not critical safety data. Congress has not yet asked Boeing's CEO to testify about the 737 Max crisis.