The Bell OH-58 Kiowa is a family of single-engine single-rotor military helicopters used for observation, utility, and direct fire support. It was produced by the American manufacturer Bell Helicopter and is closely related to the Model 206A JetRanger civilian helicopter.
The OH-58 was originally developed during the early 1960s as the D-250 for the Light Observation Helicopter (LOH). While the rival Hughes OH-6 Cayuse was picked over Bell's submission in May 1965, the company refined its design to create the Model 206A, a variant of which it successfully submitted to the reopened LOH competition two years later. The initial model, designated by the service as the OH-58A, was introduced in May 1969. Successive models would follow, often with uprated engines, enhanced protection systems, and other improvements, culminating in the OH-58F. Additional improvements, such as the OH-58X, were proposed but ultimately not pursued.
During the 1970s, the US Army became interested in pursuing an advanced scout helicopter, for which the OH-58 would be further developed, evaluated, and ultimately procured as the OH-58D Kiowa Warrior. The OH-58D is equipped to perform armed reconnaissance missions and to provide fire support to friendly ground forces; it is equipped with a distinctive Mast Mounted Sight (MMS) containing various sensors for target acquisition and laser designation. Another visible feature present on most OH-58s are knife-like extensions above and below the cockpit that form part of the passive wire strike protection system. The early-build OH-58s were equipped with a two-bladed main rotor, while the OH-58D and newer variants have a four-bladed rotor.
The OH-58 was primarily produced for the United States Army. Only two months after the type's entry to service, it was first deployed into the Vietnam War. The US Army would make extensive use of various OH-58 models across numerous war zones over the decades, seeing active combat during the Gulf War, the Invasion of Panama, and the War in Afghanistan among others. During 2017, the US Army opted to withdraw its remaining OH-58s, making use of alternative rotorcraft, such as the Boeing AH-64 Apache and Eurocopter UH-72 Lakota, as well as increasing use of unmanned aerial vehicles (UAVs), to fill the role. Furthermore, the OH-58 has been exported to Austria, Canada, Croatia, the Dominican Republic, Taiwan, Saudi Arabia, and Greece. It has also been produced under license in Australia.
On 14 October 1960, the United States Navy approached 25 helicopter manufacturers to request on behalf of the Army the submission of proposals for a Light Observation Helicopter (LOH). Bell Helicopter was one of the manufacturers approached, and chose to enter the competition along with 12 other manufacturers, including Hiller Aircraft and Hughes Tool Co., Aircraft Division.[5] Bell's design was internally referred to as the D-250, and would be officially designated as the YHO-4.[6] On 19 May 1961, Bell and Hiller were announced as winners of the design competition.[7][8]
Bell developed the D-250 design into the Model 206, while the HO-4 designation was changed to YOH-4A in 1962, and produced five prototype aircraft for the Army's test and evaluation phase. On 8 December 1962, the first prototype performed its maiden flight.[9] The YOH-4A was also called the Ugly Duckling in comparison to other contending aircraft.[9] After a fly off of the Bell, Hughes and Fairchild-Hiller prototypes, the Hughes OH-6 Cayuse was selected in May 1965.[10]
When the YOH-4A was rejected by the Army, Bell went about solving the problem of marketing the aircraft. In addition to the image problem, the helicopter lacked cargo space and only provided cramped quarters for the planned three passengers in the back. The solution was a fuselage redesigned to be more sleek and aesthetic, adding 16 cubic feet (0.45 cubic metres) of cargo space in the process.[11] The redesigned aircraft was designated as the Model 206A, and Bell President Edwin J. Ducayet named it the JetRanger denoting an evolution from the popular Model 47J Ranger.
In 1967, the Army reopened the LOH competition for bids because Hughes Tool Co. Aircraft Division could not meet the contractual production demands.[12][13] Bell resubmitted for the program using the Bell 206A.[6] Fairchild-Hiller failed to resubmit their bid with the YOH-5A, which they had successfully marketed as the FH-1100.[14] In the end, Bell underbid Hughes to win the contract and the Bell 206A was designated as the OH-58A. Following the U.S. Army's naming convention for helicopters, the OH-58A was named Kiowa in honor of the Native American tribe.[15]
In the 1970s, the U.S. Army began evaluating the need to improve the capabilities of their scout aircraft. Anticipating the AH-64A's replacement of the venerable AH-1, the Army began shopping the idea of an Aerial Scout Program to stimulate the development of advanced technological capabilities for night vision and precision navigation equipment. The stated goals of the program included prototypes that would:
...possess an extended target acquisition range capability by means of a long-range stabilized optical subsystem for the observer, improved position location through use of a computerized navigation system, improved survivability by reducing aural, visual, radar, and infrared signatures, and an improved flight performance capability derived from a larger engine to provide compatibility with attack helicopters.[16]
During March 1974, the Army created a special task force at Fort Knox to develop the system requirements;[17] by the following year, the task force had devised the requirements for an Advanced Scout Helicopter (ASH) program. The requirements were formulated around an rotorcraft capable of performing in day, night, and adverse weather, and compatible with all advanced weapons systems planned for development and fielding into the 1980s. The program was approved by the System Acquisition Review Council and the Army prepared for competitive development to begin the next year.[18] However, as the Army tried to get the program off the ground, Congress declined to provide funding in the fiscal year 1977 budget and the ASH Project Manager's Office (PM-ASH) was closed on 30 September 1976.[19]
While no development occurred for some years, the program survived as a requirement without funding. On 30 November 1979, the decision was made to defer development of an advanced scout helicopter in favor of modifying existing airframes in inventory as a near term scout helicopter (NTSH) option. The development of a mast-mounted sight would be the primary focus to improve the ability to perform reconnaissance, surveillance, and target acquisition missions while remaining hidden behind trees and terrain. Both the UH-1 and the OH-58 were evaluated as NTSH candidates, but the UH-1 was dropped from consideration due to its larger size and ease of detection. The OH-58, on the other hand demonstrated a dramatic reduction in detectability with a Mast-Mounted Sight (MMS).[citation needed]
On 10 July 1980, the Army decided that the NTSH would be a competitive modification program based on developments in the commercial helicopter sector, particularly Hughes Helicopters' Hughes 500D, which had made major improvements over the OH-6.[20]
The Army's decision to acquire the NTSH resulted in the "Army Helicopter Improvement Program (AHIP)". Both Bell Helicopter and Hughes Helicopters redesigned their scout aircraft to compete for the contract. Bell offered a more robust version of the OH-58 in their Model 406,[21] and Hughes offered an upgraded version of the OH-6. On 21 September 1981, Bell Helicopter Textron was awarded a development contract.[22][23] On 6 October 1983, the first prototype performed its maiden flight,[4] and the aircraft entered service two years later as the OH-58D.[24]
Initially intended for attack, cavalry, and artillery roles, the Army only approved a low initial production level and confined the OH-58D's role to field artillery observation. The Army also directed that a follow-on test be conducted to further evaluate it due to perceived deficiencies. On 1 April 1986, the Army formed a task force at Fort Rucker, Alabama, to remedy deficiencies in the AHIP.[24] During 1988, the Army had planned to discontinue the OH-58D and focus on the LHX; however, Congress approved $138 million to expand the program, calling for the AHIP to operate with the Apache as a hunter/killer team; the AHIP would locate targets and the Apache would destroy them in a throwback to the traditional OH-58/AH-1 relationship.[25]
The Secretary of the Army directed instead that the aircraft's armament systems be upgraded, based on experience with Task Force 118's performance operating armed OH-58Ds in the Persian Gulf in support of Operation Prime Chance, and that the type be used primarily for scouting and armed reconnaissance.[26] The armed aircraft would be known as the OH-58D Kiowa Warrior, denoting its new armed configuration. Beginning with the 202nd aircraft (s/n 89-0112) in May 1991, all remaining OH-58Ds were produced in the Kiowa Warrior configuration. During January 1992, Bell received its first retrofit contract to convert all remaining OH-58Ds to the Kiowa Warrior configuration.[4]
Overall 2,325 OH-58 were produced, with an additional 56 Bell 206B-1 also built. Production of new airframes for the A and B models ended in 1977, and the D model in 2000. Conversions of early models to the D standard continued afterward.[2]
The Bell OH-58 Kiowa is a family of single-engine single-rotor military helicopters principally used for observation, utility, and direct fire support. The primary role of the original OH-58A was to identify targets for other platforms, such as the Bell AH-1 Cobra attack helicopter and ground artillery; it lacked any armaments and weighed 1,451 kg (3,200 lb) when fully loaded, being able to carry a small amount of cargo or up to two passengers.[13] While initial examples were reliant on the crew to conduct observations, later models were furnished with sophisticated sensors to precisely determine a target's location. Payload capacity was also increased considerably on later-build rotorcraft, the OH-58D Kiowa was designed to carry a maximum load of 2,495 kg, 72% more capacity than the original version.[13]
Early Kiowas were fitted with a flexible twin-bladed main rotor; starting with the OH-58D, a four-bladed rigid main rotor was used.[13] This was entirely composed of composite materials, the OH-58D was the first US Army rotorcraft to incorporate an all-composite main rotor hub. Later models were outfitted as light gunships, being equipped with various armaments, such as Stinger air-to-air missiles, a .50-caliber machine gun, podded 70mm Hydra rockets and AGM-114 Hellfire air to ground missiles.[13] Other areas of improvement were the avionics and the cockpit; new navigation and communication systems were installed along with new and larger flight instrumentation, while all light sources were redesigned for compatibility with Night Vision Goggles (NVG). Later versions were outfitted with a glass cockpit, which retained conventional instrumentation as a fallback measure.[13]
The OH-58D introduced perhaps the most distinctive feature of the Kiowa family — the Mast Mounted Sight (MMS), which resembles a beach ball perched above the rotor system. The MMS by Ball Aerospace & Technologies has a gyro-stabilized platform containing a television system (TVS), a thermal imaging system (TIS), and a laser range finder/designator (LRF/D). These features gave the OH-58D the additional mission capability of target acquisition and laser designation in day or night, limited-visibility and adverse weather.[27] In combination with the 1553 databus, the OH-58D being first US Army helicopter to be fielded with such equipment, target data from the sensors could be directly passed to precision-guided weapons.[13]
The MMS was developed by the McDonnell Douglas Corp. in Huntington Beach, CA. Production took place primarily at facilities in Monrovia, CA. As a result of a merger with Boeing, and a later sale of the business unit, the program is currently owned and managed by DRS Technologies, with engineering support based in Cypress, CA, and production support taking place in Melbourne, FL.[28] On the OH-58F, the MMS was removed, its functions having been replaced by the AAS-53 Common Sensor Payload, which is mounted on the chin.[13]
One distinctive feature of operational OH-58s are the knife-like extensions above and below the cockpit which are part of the passive wire strike protection system; it protects 90% of the frontal area of the helicopter from wire strikes that can be encountered at low altitudes by directing wires to the upper or lower blades before they can entangle the rotor blade or landing skids. The OH-58 was the first helicopter to test this system, after which the system was adopted by the US Army for the OH-58 and most of their other helicopters.[29] Various other defensive and survivability measures were incorporated, such as ballistic floor armor, a missile warning system, crashworthy seats, and infrared suppression systems for the engine exhaust.[13]
In May 1969, the first OH-58A Kiowa was officially received at a ceremony held at Bell Helicopter's Fort Worth plant, officiated by Major General John Norton, commanding general of the Army Aviation Materiel Command (AMCOM).[30] Two months later, on 17 August 1969, production OH-58A helicopters arrived in South Vietnam for the first time;[31] their deployment was accompanied by a New Equipment Training Team (NETT) comprising personnel from both the US Army and Bell Helicopters.[32] Although the Kiowa production contract had replaced the LOH contract with Hughes, the OH-58A did not automatically replace the OH-6A in operations; subsequently, the Kiowa and the Cayuse would continue operating in the same theater until the end of the conflict.
On 27 March 1970, an OH-58A Kiowa (s/n 68-16785) was shot down over South Vietnam, one of the first OH-58A losses of the war. The pilot, Warrant Officer Ralph Quick Jr., was flying Lieutenant Colonel Joseph Benoski Jr. as an artillery spotter. After completing a battle damage assessment for a previous fire mission, the aircraft was damaged by .51 inch (13 mm) machine gun fire and crashed, killing both crew members. Approximately 45 OH-58A helicopters were destroyed during the Vietnam War due to combat losses and accidents.[33] One of the last combat losses in the theatre was of an OH-58A (s/n 68-16888) from A Troop, 3-17th Cavalry, flown by First Lieutenant Thomas Knuckey. On 27 May 1971, Lieutenant Knuckey was also flying a battle damage assessment mission when his aircraft came under machine gun fire and exploded. Knuckey and his observer, Sergeant Philip Taylor, both died in the explosion.[34]
During early 1988, it was decided that armed OH-58D (AHIP) helicopters from the 118th Aviation Task Force would be phased in to replace the SEABAT (AH-6/MH-6) teams of Task Force 160th to carry out Operation Prime Chance, the escort of oil tankers during the Iran–Iraq War. On 24 February 1988, two AHIP helicopters reported to the Mobile Sea Base Wimbrown VII, and the helicopter team ("SEABAT" team after their callsign) stationed on the barge returned to the United States. For the next few months, the AHIP helicopters on the Wimbrown VII shared patrol duties with the SEABAT team on the Hercules. Coordination proved difficult, despite frequent requests from TF-160, the SEABAT team on the Hercules was not replaced by an AHIP detachment until June 1988.[35] The OH-58D helicopter crews involved in the operation received deck landing and underwater survival training from the Navy.
In November 1988, the number of OH-58D helicopters that supported Task Force 118 was reduced. However, the rotorcraft continued to operate from the Navy's Mobile Sea Base Hercules, the frigate Underwood, and the destroyer Conolly. OH-58D operations primarily entailed reconnaissance flights at night, and depending on maintenance requirements and ship scheduling, Army helicopters usually rotated from the mobile sea base and other combatant ships to a land base every seven to fourteen days. On 18 September 1989, an OH-58D crashed during night gunnery practice and sank, but with no loss of personnel. When the Mobile Sea Base Hercules was deactivated in September 1989, all but five OH-58D helicopters redeployed to the continental United States.[36]
During Operation Desert Shield (the build-up to Operation Desert Storm) U.S. Army OH-58Ds would exercise alongside USMC AH-1Ws and assist with targeting and laser spotting. However while this tactic worked and was effective, there is little evidence that this tactic was used, likely to a lack of OD-58Ds.[37]
During Operation Desert Storm, 130 deployed OH-58D helicopters worked alongside the other Army attack helicopters, 145 AH-1 Cobras and 277 AH-64 Apaches,[37] and participated in a wide variety of critical combat ground forces mission. During Operation Desert Shield and Operation Desert Storm, the Kiowas collectively flew nearly 9,000 hours with a 92 percent fully mission capable rate. The Kiowa Warrior had the lowest ratio of maintenance hours to flight hours of any combat helicopter in the war.[38]
The "Army attack helicopters" also worked jointly with close air support and support aircraft such as the USAF A-10As, F-16A/Cs, EF-111As, EC-130H Compass Call, RF-4G Phantom II 'Wild Weasel,' and E-8 Joint STARS.[37]
In 1989, Congress mandated that the Army National Guard would take part in the country's War on Drugs, enabling them to aid federal, state and local law enforcement agencies with "special congressional entitlements". In response, the Army National Guard Bureau created the Reconnaissance and Aerial Interdiction Detachments (RAID) in 1992, consisting of aviation units in 31 states with 76 specially modified OH-58A helicopters to assume the reconnaissance/interdiction role in the fight against illegal drugs. During 1994, 24 states conducted more than 1,200 aerial counterdrug reconnaissance and interdiction missions, conducting many of these missions at night.[39] Eventually, the program was expanded to cover 32 states and consisting of 116 aircraft, including dedicated training aircraft at the Western Army Aviation Training Site (WAATS) in Marana, Arizona.[40]
The RAID program's mission has now been expanded to include the war against terrorism and supporting U.S. Border Patrol activities in support of homeland defense. The National Guard RAID units' Area of Operation (AO) is the only one in the Department of Defense that is wholly contained within the borders of the United States.[40]
During Operation Just Cause in 1989, a team consisting of an OH-58 and an AH-1 were p