The OV-10 served in the U.S. Air Force, U.S. Marine Corps, and U.S. Navy, as well as in the service of a number of other countries. A total of 81 OV-10 Broncos were ultimately lost to all causes during the course of the Vietnam War, with the Air Force losing 64, the Navy 7 and the Marines 10.
U.S. Marine Corps
The OV-10 was first acquired by the U.S. Marine Corps. Each of the Marine Corps' two observation squadrons (designated VMO) had 18 aircraft – nine OV-10As and nine OV-10Ds night observation aircraft. A Marine Air Reserve observation squadron was also established. The OV-10 operated as a forward air controller and was finally phased out of the Marine Corps in 1995 following its employment during Operation Desert Storm, which also saw the final combat losses of OV-10s by U.S. forces. Among these losses were two USMC OV-10s being shot down due to a lack of effective infrared countermeasures. It was also thought that the slow speed made it more vulnerable to anti-aircraft weapons. Forward air control passed mostly to ground units with laser designators and digital radios (GFACs) and the twin-seat F/A-18D Hornet (FAC(A)s). Most operational Broncos were reassigned to civil government agencies in the U.S., while some were sold to other countries.
The U.S. Marine Corps YOV-10D Night Observation Gunship System (NOGS) program modified two OV-10As (BuNo 155395 and BuNo 155396) to include a turreted forward looking infrared (FLIR) sensor, laser target designator and turreted 20 mm (.79 in) XM197 gun slaved to the FLIR aimpoint. NOGS succeeded in Vietnam, but funds to convert more aircraft were not approved. NOGS evolved into the NOS OV-10D, which included a laser designator, but no gun.
U.S. Air Force
The USAF acquired the Bronco primarily as an FAC aircraft. The first combat USAF OV-10As arrived in Vietnam on 31 July 1968 as part of "Operation Combat Bronco", an operational testing and evaluation of the aircraft. These test aircraft were attached to the 19th Tactical Air Support Squadron, 504th Tactical Air Support Group at Bien Hoa Air Base in South Vietnam. The test roles included the full range of missions then assigned to FAC aircraft, including day and night strike direction, gunship direction, bomb damage assessment, visual reconnaissance, aerial artillery direction, and as escorts for aircraft engaged in Operation Ranch Hand. The aircraft's ability to generate smoke internally was utilized for strike direction and "in four specific instances under conditions of reduced visibility, the smoke was seen by strike aircrews before the detected." Operation Combat Bronco ended on 30 October 1968.
After the end of Combat Bronco, the USAF began to deploy larger numbers to the 19th TASS (Bien Hoa), 20th TASS (Da Nang Air Base), and for out-of-country missions to the 23d TASS (Nakhom Phanom in Thailand). The 23d TASS conducted Operation Igloo White, Operation Prairie Fire/Daniel Boone, and other special operations missions.
In April 1969 the USAF conducted an operational exercise, called Misty Bronco, to evaluate the OV-10A's performance as a light strike aircraft. The results were positive and as of October 1969 all USAF OV-10As were to be armed with their internal .308 in (7.62 mm) M60C machine guns, which had generally been left out during the Combat Bronco evaluations and subsequent deployment. High explosive 2.75 in (70 mm) rockets were also authorized for use against ground targets.
In 1971, the 23d TASS's OV-10A Broncos received modifications under project Pave Nail. Carried out by LTV Electrosystems during 1970, these modifications primarily included the addition of the Pave Spot target laser designator pod, as well as a specialized night periscope (replacing the initial starlight scopes that had been used for night time operations) and LORAN equipment. The callsign Nail was the radio handle of this squadron. These aircraft supported interdiction of troops and supplies on the Ho Chi Minh Trail by illuminating targets for laser-guided bombs dropped by McDonnell F-4 Phantom IIs. After 1974, these aircraft were converted back to an unmodified OV-10A standard.
At least 157 OV-10As were delivered to the USAF before production ended in April 1969. The USAF lost 64 OV-10 Broncos during the war, to all causes. In the late 1980s, the USAF started to replace their OV-10s with OA-37B and OA-10A aircraft. Unlike the Marine Corps, the USAF did not deploy the Bronco to the Middle East in response to the Iraqi invasion of Kuwait, as it believed that the OV-10 was too vulnerable. The final two USAF squadrons equipped with the Bronco, the 19th and 21st Tactical Air Support Squadron (TASS) retired the OV-10 on 1 September 1991.
The U.S. Navy formed Light Attack Squadron Four (VAL-4), the "Black Ponies", on 3 January 1969, and operated in Vietnam from April 1969 to April 1972. The Navy used the Bronco OV-10A as a light ground attack aircraft, for interdiction of enemy logistics, and fire-support of Marines, SEALs and naval riverine force vessels. It succeeded in this role, although the U.S. Navy did lose seven OV-10s during the Vietnam War to various causes. Other than OV-10 Fleet replacement training done in cooperation with Air Antisubmarine Squadron Forty-One (VS-41) at NAS North Island, California, VAL-4 was the only squadron in the U.S. Navy to ever employ the OV-10 and it was decommissioned shortly following the end of the Vietnam War. VAL-4's surviving OV-10s were subsequently transferred to the Marine Corps.
In 1991, the USAF provided the Colombian Air Force with 12 OV-10As. Later, three ex-USMC A-models were also acquired to provide parts support. Colombia operates the aircraft in a COIN role against an active insurgency. At least one aircraft has been lost in combat. The remaining OV-10As were upgraded to OV-10D standard.
The OV-10B variant was produced for Germany to use as target tug. 18 aircraft were delivered in the late 60's and they were equipped with target towing equipment inside the fuselage. A clear dome replaced the rear cargo door and a rear seat was installed in the cargo bay to look backwards out of the dome. After a long career the Bronco was replaced by the Pilatus PC-9 in 1990 and all aircraft were retired and send to various museums, technical schools and used as ABDR (Aircraft Battle Damage Repair).
Indonesia purchased 12 OV-10F aircraft and operates them in COIN operations similar to the U.S. Navy's Vietnam missions with their Broncos, but have retrofitted .50 in (12.7 mm) Browning heavy machine guns in place of the .308 in (7.62 mm) machine guns. These aircraft were based in Lanud Abdulrachman Saleh Air Force Base in Malang, East Java and were vital in the invasion of East Timor and ensuing COIN operations. In 1977, they were also used during the aerial bombardments of Amungme villages near Freeport-McMoRan area of operations, West Papua, in response to OPM attacks on the mining company facilities, and of Dani villages in Baliem Valley, also in West Papua, in response to rebellion against enforced participation in the Indonesian general election. Due to the lack of U.S. bombs, the Indonesian Air Force modified the bomb racks of to be able to carry Russian bombs. The Indonesian Air Force plans to replace their OV-10Fs with EMBRAER Super Tucanos following a fatal accident on the 23 July 2013.
The Philippine Air Force (PAF) received 24 OV-10As from U.S. stocks in 1991, later followed by a further nine from the United States, and eight ex-Thai Air Force OV-10Cs in 2003–2004. The OV-10s are operated by the 16th Attack Squadron and 25th Composite Attack Squadron of the 15th Strike Wing, based in Sangley Point, Cavite. The PAF flies Broncos on search-and-rescue and COIN operations in various parts of the Philippines. The first two women combat pilots in the PAF flew OV-10s with the 16th. This squadron flew anti-terrorist operations in the Jolo Islands.
PAF OV-10 Broncos have been repeatedly used in air strikes against Moro Islamic Liberation Front positions during ongoing fighting in 2011, and two were used in an air strike on February 2012 which resulted in the death of three Abu Sayyaf and Jemaah Islamiyah commanders, among others. Philippine Air Force OV-10s have been reportedly modified in order to employ modern smart bombs.
The Royal Thai Air Force purchased 32 new OV-10C aircraft in the early 1970s for COIN usage. Reportedly Broncos won most Thai bombing competitions until F-5Es became operational. At one time The RTAF flew OV-10s as air-defense aircraft. In 2004, RTAF donated most of the OV-10s to the Philippines. Two OV-10 survivors are displayed in the Tango Squadron Wing 41 Museum in Chiang Mai and the RTAF Museum in Bangkok. The remaining OV-10s will be donated to the PAF in 2011.
The Venezuelan Air Force has operated a number of new build OV-10Es and ex-USAF OV-10As over the years. On 27 November 1992, the aircraft were widely used by mutinied officers who staged an attempted coup d'état against former President Carlos Andrés Pérez. The rebels dropped bombs and launched rockets against Police and government buildings in Caracas. Four Broncos were lost during the uprising, including two shot down by a loyalist General Dynamics F-16 Fighting Falcon.
Venezuela's OV-10s are to be retired in the coming years. Originally Venezuela attempted to procure Embraer Super Tucano aircraft to replace the OV-10, but no deal was achieved which President Chavez claimed was due to the result of pressure from the U.S. government. The Venezuelan government has decided not to replace them with new fixed wing aircraft. Rather, the Venezuelan Air Force is replacing them with the Russian made Mil Mi-28 attack helicopter.
NASA has used a number of Broncos for various research programs, including studies of low speed flight carried out with the third prototype in the 1970s, and studies on noise and wake turbulence. One OV-10 remained in use at NASA's Langley base in 2009 with 3 additional aircraft obtained from the Department of State formerly used in drug eradication efforts.
U.S. Department of State Air Wing
The Department of State (DoS) aircraft are former Air Force OV-10A and Marine Corps OV-10D aircraft operated under contract by DynCorp International in support of U.S. drug interdiction and eradication efforts in South America. The aircraft carry civilian U.S. aircraft registration numbers and, when not forward deployed, are home based at a DoS/DynCorp facility at Patrick Air Force Base, Florida.
Bureau of Land Management
The Bureau of Land Management (BLM) acquired seven OV-10As for use as fire fighting aircraft, including the YOV-10A prototype. In this role, they would lead firefighting air tankers through their intended flight path over their target area. The aircraft were operated in their basic military configurations, but with their ejection seats disabled. The aircraft's existing smoke system was used to mark the path for the following air tankers. With the age of the aircraft, spare parts were difficult to obtain, and the BLM retired their fleet in 1999.
California Department of Forestry and Fire Protection
The California Department of Forestry and Fire Protection (CDF or CALFIRE) has acquired a number of OV-10As, including the six surviving aircraft from the BLM and 13 former U.S. Marine Corps aircraft in 1993 to replace their existing Cessna O-2 Skymasters as air attack aircraft. The CAL FIRE Broncos fly with a crew of two, a contract pilot and the CAL FIRE ATGS or Air Tactical Group Supervisor, whose job it is to coordinate all aerial assets on a fire with the Incident Commander on the ground. Thus, besides serving as a tanker lead-in aircraft, the OV-10A is also the aerial platform from which the entire air operation is coordinated.