(WASHINGTON) — Lawmakers on Wednesday grilled the head of the Federal Aviation Administration over how his agency handled the safety certification of the Boeing 737 MAX 8 following two crashes that left more than 340 people dead.Acting Administrator Daniel Elwell faced questions from members of the House Transportation Committee about the FAA’s role in approving the now grounded plane.”The FAA has a credibility problem,” said House Transportation subcommittee chairman Rep. Rick Larsen, D-W.Va. “The FAA must take steps to restore the public’s confidence.””In the U.S., the 737 MAX will return to service only when the FAA’s analysis of the facts and technical data indicate that it is safe to do so,” Elwell said in his opening remarks. Wednesday’s hearing marked the first in a series of investigations into why regulators or Boeing did not require pilots to go through training for the scrutinized automated safety system suspected in playing a critical role in the two crashes and why that system wasn’t detailed in the plane’s flight manual prior to the Lion Air crash in Indonesia last fall. An Ethiopian Airlines 737 MAX 8 crashed in March.The MCAS, or Maneuvering Characteristics Augmentation System, is designed to automatically drop the nose of the aircraft if sensors mounted on the nose of the aircraft detect the plane potentially entering a stall, a dangerous situation for an aircraft at low altitude.”How can we have a single point of failure in a modern aircraft?” Rep. Peter DeFazio, D-Ore., asked in his opening statements.He said the the parents of 24-year-old Samya Stumo – killed in the Ethiopia Airlines crash were in the audience.”Their daughter was flying from Ethiopia to Kenya for work when Ethiopian Airlines Flight 302 went down,” DeFazio said. “They deserve answers and accountability, as does the general flying public.”This is a developing story. Please check back for updates.Copyright © 2019, ABC Radio. All rights reserved.