The U.S. Department of Transportation will review airline security in the wake of the Germanwings plane crash that killed 150 people, and which is believed to have been caused by a pilot who locked the cockpit and deliberately steered the aircraft into the French Alps.
The audit was requested by Sen. Dianne Feinstein, a Democrat representing California, the department said in a letter to the Federal Aviation Administration.
The audit will look at whether security and hiring standards are stringent enough to prevent a similar tragedy.
Related: Families of Germanwings Victims Prepare Lawsuit in the U.S.
Germanwings pilot Andreas Lubitz suffered severe depression and may have feared losing his job before he steered the Airbus A320 into the mountains on March 24, German prosecutors have said. Three Americans were among those killed.
The audit will also examine "what steps FAA takes to evaluate the psychological health of pilots," according to the letter.
Related: Doctors Felt Germanwings Pilot Unfit to Fly, Prosecutor Says
All airline pilots should undergo psychological testing and two crew members should be in the cockpit at all times, experts told a European Union panel in July.
Since the Sept. 11, 2001, terror attacks, all aircraft in the U.S. have been required to have cockpits that lock from the inside and have reinforced doors.
The letter sent to the FAA also referred to a 2014 incident in which a Jet Blue pilot ran through a plane's cabin yelling about Jesus and the terror group al Qaeda before he was restrained by passengers.
