The Lockheed A-29 was the USAAF designation given to Lockheed Hudsons powered by Wright R-1820 engines and produced under the lend-lease agreement. The A-29 was produced in two variants, both of which entered British and Commonwealth service as the Hudson Mk.IIIA. The A-29-LO was identical to the Hudson Mk.III(LR). They were powered by 1,200hp Wright R-1820-87 engines, armed with seven .303in machine guns, and equipped with extra fuel tanks in the wings. The A-29A-LO was similar to the A-29, but had an interior that could easily be converted to carry troops.
A total of 416 A-29-LOs were built, serving with seven armed forces in six countries. The largest number went to the USAAF (153), followed by the RCAF (133), the RAAF (41), the RAF (32), the Chinese Air Force (23), the US Navy (20, as the PBO-1) and the RNZAF (14). A further 384 A-29A-LOs were producing, bringing the total number of A-29s to 800. This time the RAF received 289 aircraft, the RAAF (65), the RNZAF (23), the RCAF (4) and the Chinese Air Force (3).
The USAAF was the second largest user of the A-29-LO, taking 153 of the 416 that were produced, although very few of these aircraft actually saw combat. These aircraft never received the Boulton-Paul turret used on British aircraft, and instead were armed with a .50in gun in a flexible mounting. The 13th and 30th Bombardment Groups on the east coast of the United States and the 41st Bombardment Group on the west coast all trained with the A-29, but only the 13th Bombardment Group actually used them in combat, flying anti-submarine patrols over the Atlantic. On 7 July 1942 an A-29 of the 13th Bombardment Group became the first USAAF aircraft to sink a U-boat, destroying U-701. The group operated the A-29 alongside B-18s and B-25s, before being inactivated on 30 November 1942.
Twenty four of the existing A-29s were adapted to serve as photographic mapping aircraft, and given the designation A-29B. They operated with the 1st Photographic Group, which flew aerial mapping missions over the United States, central and southern America, the Caribbean, North Africa and the Middle East and the Kuril Islands.