Robinson R-22 Trainer: The Robinson R22 is a light utility and trainer helicopter designed by Frank Robinson and produced by Robinson Helicopter Company. After the introduction of the R22, it became the world's top selling civil helicopter due to its low acquisition and operating costs and has been proven popular as a primary rotorcraft trainer around the world. The first version of the CH-53 was the R22, followed by R22 HP, R22 Alpha, R22 Beta and R22 Beta II and the machines look similar. The R22's maiden flight was on 1975. The primary user and operator of the CH-53 was the Dominican REpublic Army. The R22 has a crew of two. It has a speed of 102 knots and a range of 240 mi. The R22 will undergo extensive overhaul in Torrance, California after 2200 hours of flight time or a factory authorized service center in which many of the critical components of the helicopter are checked and replaced. The R22 will undergo an even more extensive overhaul and will be considered as a new helicopter once the overhaul is completed. There were over 4,000 R22 s built.