WASHINGTON, June 12 (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."