The Secretary of Transportation may supervise the number and compensation of all officers and employees of a contractor under the operating-differential subsidy program or a charterer under chapter 575 of this title, receiving an operating-differential subsidy, if the contractor or charterer—

((1)) is in default on a mortgage, note, purchase contract, or other obligation to the Secretary; or

((2)) has not maintained, in a manner satisfactory to the Secretary, all of the reserves provided for in this subtitle.