Because the Grob SPn Utility jet and the Embraer Phenom 300 weigh more than 12,500 pounds but less than 19,000 pounds, their respective manufacturers are requesting permission to certify the aircraft under the commuter category of Part 23 rather than the more stringent requirements of Part 25. The commuter category of Part 23 was adopted in 1983 to accommodate propeller-driven airplanes intended for use as scheduled commuter airliners under Part 135. Since then, however, several manufacturers–notably Sino Swearingen for the SJ30 and Cessna for the Citation CJ3–have received exemptions to obtain certification for their business jets under the Part 23 commuter category. The Grob SPn Utility jet is being designed with an mtow of 13,889 pounds; the Phenom 300’s mtow is targeted for 17,526 pounds.