Top Senate appropriators pressed the Federal Aviation Administration chief to respond after a federal investigator found that safety inspectors lacked sufficient training to certify Boeing 737 Max pilots.

Susan Collins, R-Maine, and Jack Reed, D-R.I., the chairwoman and ranking member of the Senate Transportation-HUD Appropriations Subcommittee, asked FAA chief Steve Dickson in a letter Tuesday provide more information about the U.S. Office of Special Counsel’s report and the FAA’s response to it.

[Boeing 737 Max grounded following international accidents, downs U.S. export numbers]

The senators’ Tuesday letter to  Dickson requested additional information about the training of the inspectors.

“We are particularly concerned about the Special Counsel’s findings that inconsistencies in training requirements have resulted in the FAA relaxing safety inspector training requirements and thereby adopting ‘a position that encourages less qualified, accredited, and trained safety inspectors,’” Collins and Reed wrote.

A Sept. 23 letter from Office of Special Counsel Henry J. Kerner to President Donald Trump and members of Congress concluded that FAA safety inspectors “lacked proper training and accreditation” to certify pilots, including those flying the Boeing 737 Max, putting air travelers at risk.

The Kerner letter also accused FAA Deputy Administrator Daniel K. Elwell of making inaccurate statements about the training and accreditation of Aviation Safety Inspectors to Senate Commerce Chairman Roger Wicker, R-Miss.

At a House Transportation-HUD Appropriations Subcommittee oversight hearing last week, Elwell said he “fundamentally disagrees” with Kerner’s conclusion, saying a whistleblower’s complaints about inadequate training that triggered the investigation were limited to the Gulfstream VII aircraft — not the Boeing 737 Max.

Elwell said the training issue identified by the FAA’s independent auditor was related solely to whether safety inspectors who certified pilots for the Gulfstream VII needed to have classroom training or whether on-the-job training could suffice.

He said many of the safety inspectors are former pilots who have “thousands” of hours of experience.

Collins and Reed also sought documents confirming that all FAA employees serving on the boards certifying pilots for the Boeing 737 Max and the Gulfstream VII “had the required foundational training in addition to any other specific training requirements.”

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“If such training requirements were not met, please specify which aircraft certifications were compromised by insufficient FAA oversight of pilot accreditation,” they wrote.

Collins and Reed also sought a copy of a safety review panel that found that the FAA managers had created “an environment of mistrust that hampers the ability of the agency to work effectively,” according to a report in the New York Times.

And they sought explanation about the FAA’s decision not to ground the 737 Max following the October 2018 crash of Lion Air flight 610 which killed 189. An Ethiopian Airlines crash in March killed 157. Both aircraft were Boeing 737 Max jets, and the U.S. grounded the aircraft in March after the second crash.

Both crashes are believed to have been caused in part by a faulty system that erroneously reported the airplane was stalling. In the aftermath of those accidents, some pilots have complained that they were not appropriately briefed about the system and its risks.