windscreens as an attempt to reduce glint from the sun, which could reveal its location to enemies. The windscreens had a negative effect of limiting the crew's forward view, a previous strength of the original design. The aircraft was also equipped with a larger instrument panel, roughly a third bigger than the OH-58A panel, which held larger flight instruments. The panel was also equipped with Night Vision Goggle (NVG) compatible cockpit lighting. The OH-58C were also the first U.S. Army scout helicopter to be equipped with the AN/APR-39 radar detector, which alerted the crew to active anti-aircraft radar systems nearby. Some OH-58Cs were armed with two AIM-92 Stingers and are sometimes referred to as OH-58C/S, the "S" referring to the Stinger addition. Called Air-To-Air Stinger (ATAS), the weapon system was intended to provide an air defense capability. The OH-58C was the final variant of the Kiowa in active service with the US Army, its final use with the service being as a training aircraft. On 9 July 2020, the US Army retired the last OH-58Cs from service. OH-58D The OH-58D (Bell Model 406) was the result of the Army Helicopter Improvement Program (AHIP). An upgraded transmission and engine gave extra power, needed for nap-of-the-earth flight profiles, and a four-bladed main rotor made it quieter than the two-bladed OH-58C. The OH-58D introduced the distinctive Mast-Mounted Sight (MMS) above the main rotor, and a mixed glass cockpit with traditional instruments as "standby" for emergencies. The Bell 406CS "Combat Scout" was based on the OH-58D (sometimes referred to as the MH-58D). Fifteen aircraft were sold to Saudi Arabia. A roof-mounted Saab HeliTOW sight system was opted for in place of the MMS. The 406CS also had detachable weapon hardpoints on each side. The AH-58D was an OH-58D version operated by Task Force 118 (4th Squadron, 17th Cavalry) and modified with armament in support of Operation Prime Chance. The weapons and fire control systems would become the basis for the Kiowa Warrior. AH-58D is not an official DOD aircraft designation, but is used by the Army in reference to these aircraft. The Kiowa Warrior, sometimes referred to by its acronym KW, is the armed version of the OH-58D. A key difference between the Kiowa Warrior and original AHIP aircraft is a universal weapons pylon found mounted on both sides of the fuselage, capable of carrying combinations of AGM-114 Hellfire missiles, air-to-air Stinger (ATAS) missiles,