Retired airline captain Chesley Sullenberger (C) testifies during the hearing on "Status of the Boeing 737 MAX: Stakeholder Perspectives" on Capitol Hill in Washington D.C., the United States, on June 19, 2019. (Xinhua/Ting Shen)

Sharon Pinkerton of Airlines for America testifies during the hearing on "Status of the Boeing 737 MAX: Stakeholder Perspectives" on Capitol Hill in Washington D.C., the United States, on June 19, 2019. (Xinhua/Ting Shen)

Photo taken on June 19, 2019 shows the hearing on "Status of the Boeing 737 MAX: Stakeholder Perspectives" on Capitol Hill in Washington D.C., the United States. (Xinhua/Ting Shen)

Captain Dan Carey of Allied Pilots Association testifies during the hearing on "Status of the Boeing 737 MAX: Stakeholder Perspectives" on Capitol Hill in Washington D.C., the United States, on June 19, 2019. (Xinhua/Ting Shen)

Retired airline captain Chesley Sullenberger testifies during the hearing on "Status of the Boeing 737 MAX: Stakeholder Perspectives" on Capitol Hill in Washington D.C., the United States, on June 19, 2019. (Xinhua/Ting Shen)

Retired airline captain Chesley Sullenberger (front, 1st R) arrives during the hearing on "Status of the Boeing 737 MAX: Stakeholder Perspectives" on Capitol Hill in Washington D.C., the United States, on June 19, 2019. (Xinhua/Ting Shen)

Randy Babbitt, former administrator of U.S. Federal Aviation Administration, testifies during the hearing on "Status of the Boeing 737 MAX: Stakeholder Perspectives" on Capitol Hill in Washington D.C., the United States, on June 19, 2019. (Xinhua/Ting Shen)

Retired airline captain Chesley Sullenberger testifies during the hearing on "Status of the Boeing 737 MAX: Stakeholder Perspectives" on Capitol Hill in Washington D.C., the United States, on June 19, 2019. (Xinhua/Ting Shen)