From Joebaughers website,
http://www.joebaugher.com/usaf_serials/1930.html31-401/404 Ford C-4A
c/n 5-AT-91/93,95. Similar to civil 5-AT-D Tri-Motor
401 (c/n 5-AT-91) stricken from the records May 26, 1938
402 (c/n 5-AT-92) stricken from the records Jul 9, 1938
403 (c/n 5-AT-93) crashed Jun 11, 1934 404 (c/n 5-AT-95) stricken from the records Jul 3, 1938
From aerofiles,
http://aerofiles.com/ford-regs.htmlU S MILITARY
28-348 4-AT-A, 13 - USAAC XC-3, dr 7/9/32 ← [3444]
29-219 5-AT-B, 38 - USAAC C-4, dr 4/29/35
29-220 4-AT-E, 80 - USAAC C-9, dr 8/2/35
29-221 4-AT-E, 81 - USAAC C-9, dr 5/25/36
29-222 4-AT-E, 82 - USAAC C-9, dr 8/6/34
29-223 4-AT-E, 83 - USAAC C-9, dr 2/13/36
29-224 4-AT-E, 84 - USAAC C-9, dr 11/1/34
29-225 4-AT-E, 85 - USAAC C-9, dr 5/1/36
29-226 4-AT-E, 86 - USAAC C-9, dr 9/3/35
31-401 5-AT-D, 91 - USAAC C-4A, dr 5/26/38
31-402 5-AT-D, 92 - USAAC C-4A, dr 7/9/38
31-403 5-AT-D, 93 - USAAC C-4A, dx 6/11/3431-404 5-AT-D, 95 - USAAC C-4A, dr 9/30/38
A-7526 4-AT-A, 4 - USN XJR-1, dr 4/30/30
A-8273 4-AT-E, 59 - USN JR-2, dr 1/31/35
A-8274 4-AT-E, 60 - USN JR-2, dr 7/31/34
A-8457 5-AT-C, 72 - USN JR-3, dr 10/6/34
A-8598 5-AT-C, 82 - USMC JR-3, dx 8/4/30
A-8599 5-AT-C, 83 - USMC JR-3, dx 3/22/33
A-8840 5-AT-C, 84 - USN RR-4, dr 4/23/37
A-9205 5-AT-D, 109 - USMC RR-5, dr 8/31/37
A-9206 5-AT-D, 105 - USN RR-5, dr 7/11/40