04/30/2012. Remarks by
Johan Visschedijk: "Two OV-10As (BuNos. 155395, 155396) were modified to YOV-10D NOGS (Night Observation/Gunship System) under a 1970 contract from the USN, to provide a new concept in night operational capability for the USMC. The first one flew for the first time on June 9, 1970 and both were combat tested in Vietnam in 1971.