Howard GH-2/3 "Nightingale"
Coast Guard Air Station San Francisco acquired two GH-3 Nightingales in mid-1944 for use as proficiency and instrument training aircraft. The air station acquired a single GH-2 in 1945 for the same use as the GH-3's. They were apparently kept for only about a year.
Arthur Pearcy, U.S. Coast Guard Aircraft Since 1916 (Annapolis: Naval Institute Press, 1991), pp. 320-321.
Gordon Swanborough & Peter M. Bowers. United States Navy Aircraft Since 1911 (Annapolis: Naval Institute Press, 1990) (revised), pp. 432-435.