The Bell 206 is a family of two-bladed, single- and twin-engined helicopters, manufactured by Bell Helicopter at its Mirabel, Quebec, plant. Originally developed as the Bell YOH-4 for the United States Army's Light Observation Helicopter program, it was not selected by the Army. Bell redesigned the airframe and successfully marketed the aircraft commercially as the five-place Bell 206A JetRanger. The new design was eventually selected by the Army as the OH-58 Kiowa. Bell also developed a seven-place LongRanger, which was later offered with a twin-engined option as the TwinRanger, while Tridair Helicopters offers a similar conversion of the LongRanger called the Gemini ST. The ICAO-assigned model designation "B06" is used on flight plans for the JetRanger and LongRanger, and the designation "B06T" is used for the twin-engined TwinRangers.
In 2007, Bell announced an upgrade program for the 206L-1 and 206L-3 which is designed to modify the aircraft to the 206L-4 configuration; modified aircraft are designated 206L-1+ and 206L-3+. Modifications include strengthened airframe structural components (including a new tailboom), improved transmission, upgraded engine for the L-1, all of which result in a maximum gross weight increase of 300 pounds and increased performance.