Bell 412

The Bell 412 is a twin-engine utility helicopter manufactured by Bell Helicopter in the United States and Canada, derived from the Bell 212 of the UH-1 Huey family. Its principal distinguishing feature is a four-blade composite main rotor in place of the 212's two-blade rotor. First flown in 1979 and certified in January 1981, it is operated in military, law enforcement, offshore oil support, and medical evacuation roles. Major military users include Canada, Italy, and Japan.

Development

Development began in the late 1970s with the conversion of two Bell 212s into 412 prototypes, fitted with a four-blade main rotor of reduced diameter. The first prototype flew in August 1979, certification followed in January 1981, and deliveries began the same month. The 412SP (Special Performance) added fuel capacity, a higher takeoff weight, and optional seating; the 412HP (High Performance), with an improved transmission, replaced it in production in 1991. The 412EP (Enhanced Performance) introduced a dual digital automatic flight control system, and Bell offered it as the 412 LUH in the U.S. Army Light Utility Helicopter competition in the early 2000s, losing to the EC145/UH-72 Lakota. The 412EPI followed in 2013. Production has taken place in Texas, Montreal, Italy (Agusta), Indonesia (Indonesian Aerospace), and Japan (Subaru/Fuji Heavy Industries). Over 1,300 had been delivered by 2022.

Design

The 412 uses a four-blade composite main rotor of 46 ft 0 in diameter, with Boeing VR-7 root and Wortmann FX 71-H-080 tip blade sections. Power comes from a Pratt & Whitney Canada PT6T Twin-Pac coupled turboshaft, rated at 1,250 shp in the PT6T-3D/-3DF installations, with a single power section able to deliver 900 shp of emergency power for 30 minutes. The 412EPI uses the electronically controlled PT6T-9 and a glass cockpit derived from the Bell 429, with a Garmin touchscreen navigation system and BLR Strake and Fast Fin modifications for hover performance. Maximum speed is 140 kn, range 529 nmi, and service ceiling 20,000 ft; capacity is up to 13 passengers or a 3,000 kg external load. The medical configuration accommodates six patients and two attendants, or two stretchers and up to four attendants.

Operational History

Military operators include Algeria, Argentina, Azerbaijan, Bahrain, Canada, Chile, Indonesia, Italy, Japan, Mexico, Norway, Pakistan, the Philippines, Saudi Arabia, South Korea, Sri Lanka, Thailand, and the United Arab Emirates. The Royal Air Force operated the Griffin HT1 as an advanced trainer from 1997 to 2018 and the Griffin HAR2 with No. 84 Squadron at RAF Akrotiri from 2003 to 2023. The Royal Netherlands Air Force retired its AB412 SAR fleet in 2015, and Poland operated a single 412HP from 1993 to 2011. On 4 April 1991 a 412SP collided with a Piper light twin over Lower Merion Township, Pennsylvania, killing seven, including a serving US senator. A Guyana Defence Force 412EP carrying two crew and five senior officers went down near the Venezuelan border on 7 December 2023.

Variants

• Bell 412SP: Special Performance version with PT6T-3BF engines, increased fuel and takeoff weight.
• Bell 412HP: High Performance version with PT6T-3BG or -3D engines and improved transmission.
• Bell 412EP: Enhanced Performance version with PT6T-3DF engines and dual digital automatic flight control.
• Bell 412EPI: Glass cockpit version with electronically controlled PT6T-9 engines.
• Bell 412CF (CH-146 Griffon): 100 utility transport helicopters built for the Canadian Forces, based on the 412EP.
• Agusta-Bell AB 412: Licence-built version produced by Agusta in Italy, including the AB 412 Grifone for the Italian Army and the AB 412 CRESO battlefield-surveillance variant.
• Griffin HT1 / HAR2: Royal Air Force advanced trainer and search-and-rescue versions of the 412EP, retired in 2018 and 2023.
• Subaru-Bell UH-2 / 412EPX: Japanese-built development of the 412EPI for the Japan Ground Self-Defense Force (formerly UH-X), with a commercial 412EPX counterpart.