14 CFR 183.11: Selection.

(a) The Federal Air Surgeon, or his or her authorized representatives within the FAA, may select Aviation Medical Examiners from qualified physicians who apply. In addition, the Federal Air Surgeon may designate qualified forensic pathologists to assist in the medical investigation of aircraft accidents.

(b) Any local Flight Standards Inspector may select a pilot examiner, technical personnel examiner, or a designated aircraft maintenance inspector whenever he determines there is a need for one.

(c)(1) The Aircraft Certification Service may select Designated Engineering Representatives from qualified persons who apply by a letter accompanied by a “Statement of Qualifications of Designated Engineering Representative.”

(2) The Aircraft Certification Service may select Designated Manufacturing Inspection Representatives from qualified persons who apply by a letter accompanied by a “Statement of Qualifications of Designated Manufacturing Inspection Representative.”

(d) The Associate Administrator for Aviation Safety, may select Designated Air Traffic Control Tower Operator Examiners.

(e) The Aircraft Certification Service may select Designated Airworthiness Representatives from qualified persons who apply by a letter accompanied by a “Statement of Qualifications of Designated Airworthiness Representative.”