The O-1 and O-2 had performed sterling work as FAC aircraft but neither was designed specifically for the role and both had limited performance, especially in terms of speed, range and weapons-carrying capability. From the outset the North American OV-10 Bronco was designed as a counter-insurgency aircraft with the secondary role of forward air control. Originating as a Marine Corps requirement, the OV-10 was eventually used by the Marines, the Air Force and the Navy in the reconnaissance and FAC roles. The aircraft’s performance was significantly better than the types it replaced and, even more important from the crew’s point of view, its huge cockpit canopy and high seating position gave it excellent visibility and the inclusion of ejection seats greatly increased crew confidence and survivability. The OV-10’s major deficiency was the loud and distinctive noise produced by its turboprop engines and high-speed propellers, which tended to give its position away to the enemy. The Marines were the first to introduce the Bronco to Southeast Asia with the arrival of the first six aircraft at Marble Mountain on 6 July. VMO-2 flew the first combat mission with the OV-10A within four hours of the first aircraft arriving on the 6th. By the end of the year a total of 26 Broncos had arrived in South Vietnam and VMO-2 and VMO-6 racked up around 3,000 sorties during 1968. The USAF received its first OV-10 on 23 February 1968 and the first Air Force aircraft arrived in South Vietnam on 31 July. Within a few months the five USAF tactical air support squadrons started to receive OV-10s to supplement their O-1s and O-2s. The third operator of the Bronco in Southeast Asia was the US Navy, which equipped a single squadron in support of riverine operations in the Mekong Delta.