Prior to the completion of the first of the 63 A-20s ordered in June of 1939, the Air Corps instructed Douglas in March of 1940 to modify three of the A-20s as prototypes for a high-speed photographic reconnaissance aircraft. The reconnaissance-adapted A-20s would serve under the designation F-3, which was in the F for photographic reconnaissance series.
The first such modification was carried out on former A-20 serial number 39-741. The aircraft was then redesignated XF-3. It was powered by a pair of two turbosupercharged R-2600-7 engines. All bomb racks were removed and a set of T-3A cameras was installed in the rear bomb bay, but the standard defensive armament of the A-20 was retained. A recognition feature for the XF-3 was a single window on each side of the fuselage at the rear of the bomb bay and a six-panel skylight in the turtle deck ahead of the dorsal gun station.
The XF-3 was delivered to the Army in April of 1942. The turbosuperchargers proved to be difficult to cool, and the aircraft was re-engined with non-turbosupercharged 1600 hp R-2600-3s and delivered to the US Navy as the BD-1 (where it carried BuNo 4251), where it was used for target towing and general utility duties.
Two aircraft originally ordered as A-20 serials 39-745 and 39-748 were completed as YF-3. The YF-3 was similar to the XF-3 in being powered by turbosupercharged R-2600-7 engines, but differed from the XF-3 in having a tail turret in which a gunner manned a pair of flexible 0.30-inch machine guns. This was the only aircraft of the series so equipped. There was no further production development.
F-3A was the designation applied to 46 transparent-nosed A-20Js and A-20Ks that were modified as night photographic reconnaissance aircraft. The two forward- firing 0.50-inch machine guns in the lower nose of the A-20J and A-20K were removed to enable the installation of cameras in the nose. Additional K-198, K-17 or K22 cameras were installed in the bomb bay and photoflash bombs could be carried in the forward section of the bomb bay. The first five F-3As were converted from A-20Js at depots, but the remainder were modified on the Santa Monica production line.
Main service use of reconnaissance Havocs began in May of 1944 when the 9th Air Force's 155th Photographic Squadron (Night) was issued F-3As for night photographic operations in the European theatre.
39-741 Douglas XF-3 Havoc - transferred to US Navy as BD-1 BuNo 4251 39-745 Douglas YF-3 Havoc 39-748 Douglas YF-3 Havoc 43-9857/9880 Douglas A-20J-10-DO Havoc 9876 converted to F-3A 43-21432/21471 Douglas A-20J-15-DO Havoc 21457/21461 converted to F-3A 43-21552/21581 Douglas A-20J-15-DO Havoc 21581 converted to F-3A 43-21988/22147 Douglas A-20J-20-DO Havoc 22091/22092 converted to F-3A 44-66/100 Douglas A-20K-5-DO Havoc 44-71 converted to F-3A 44-101/198 Douglas A-20K-10-DO Havoc 44-194/198 converted to F-3A 44-329/406 Douglas A-20K-10-DO Havoc 44-342/347 converted to F-3A 44-365/369 converted to F-3A 44-707/825 Douglas A-20K-15-DO Havoc 44-707/711 converted to F-3A 44-733/735 converted to F-3A