Every officer of the Reserve Corps being considered for reappointment shall undergo such physical examination as the Surgeon General may direct. An officer on active duty may be recommended for reappointment unless he is found to have a physical disability which is determined to render him physically unfit to perform the duties of his office under section 402 of the Career Compensation Act of 1949, as amended. An officer may be recommended for promotion only if he meets the physical qualifications for original appointment. If an officer is not available to be physically examined because of circumstances which make it impracticable for the Service to require such examination, he may, in the discretion of the Surgeon General, be reappointed without such examination, but shall be examined as soon thereafter as practicable and his physical qualification or disqualification for continued or future active service shall be determined on the same basis as if the physical examination had been given prior to reappointment.