An improved variant, the
Y1A-18, had upgraded
Wright R-1820-47 radial engines with three-blade
propellers replacing the original two-blade models. Thirteen aircraft were produced, serial numbers
37-52 through
37-64, with the first example produced (Y1A-18) first flight occurring on 3 July 1935; and although successful in testing, no further production was ordered due to a lack of funds as well as the availability of more advanced aircraft (such as the
Douglas A-20 Havoc) under design. After completion of service testing, the Y1A-18s were redesignated
A-18. They were assigned to the
8th Attack Squadron,
3rd Attack Group at
Barksdale Field,
Louisiana in 1937. During its service with the 8th Attack Squadron, the retractable landing gear of the A-18 had an inherent weakness, with no less than eight of the 13 A-18s suffering from a landing gear collapse on landing or roll-out. Lastly, four of the A-18s (serials 37-52, 37-56, 37-61, and one other un-identified) were assigned to the USAAF
Caribbean Air Force in late November 1941 and were based initially at
Albrook Field,
Panama Canal Zone. Three of the aircraft were first assigned to the Headquarters and Headquarters Squadron,
12th Pursuit Wing, while the fourth aircraft was assigned to HHS Bomber Command (later
VI Bomber Command) at Albrook. The aircraft remained with these units through February 1942. By December 1942, two or three of the aircraft were still airworthy. One was employed as a tow
target tug, the other two were operated as reconnaissance aircraft by the
108th Reconnaissance Squadron (Special) from
Howard Field, patrolling the approaches to the
Panama Canal. A-18 serial 37-61 was damaged in a landing accident at Albrook field on 22 February 1943, and cannibalization kept at least one aircraft flying until it was grounded due to a lack of spare parts. Serial 37-56 was transferred to instructional airframe training at Howard. All were eventually scrapped in the Canal Zone by the end of 1943. ==Operators==