WASHINGTON (Reuters) - The head of the Federal Aviation Administration will tell the U.S. Senate Commerce Committee on Thursday that the agency will maintain its increased on-site presence at Boeing ( BA ) and its supplier Spirit AeroSystems ( SPR ) "for the foreseeable future."

FAA Administrator Mike Whitaker will tell senators the agency's decision to boost inspections after the Jan. 5 Alaska Airlines Boeing 737 MAX 9 in-flight emergency is now permanent, according to a copy of his written testimony seen by Reuters. Whitaker will say the FAA has added "additional inspections at critical points of the production process."

Whitaker will also say that, following lessons from the Jan. 5 incident, "the FAA changed its oversight approach and those changes are permanent. We have now supplemented our audits with more active, in-person oversight - the 'audit plus inspection' approach."