complete failure and the loss of one actuator, a viable level of assisted control over the key flight surfaces remains present. Weather radar and Marconi-built solid-state instrument displays are supplied as standard, as well as a Collins-built radio set; optional long-range, radio-based equipment, such as a HF radio set and VHF navigational aids can be installed. In a standard executive aircraft configuration, the cabin is divided between the forward galley, and two seating sections, which are typically fitted with a four-chair club section followed by either a conference grouping area or divans, along with a lavatory at the aft end. The chairs are fully reclining and can swivel, while the divans can serve as sleeping accommodation. Early examples feature luxuries such as telephones, lighting controls, and stereo systems; foldaway tables attached to the cabin walls were also installed, along with a pair of wardrobes, one fore and one aft, for storing hand luggage and other small items. Variants Challenger 600 (CL-600-1A11) CL-600 Original production version, powered by Lycoming ALF 502L turbofans of 7500 lb-ft (33.6 kN) thrust each, built from 1978 to 1982 (81 built) CL-600S Three CL-600s are retrofitted with the winglets introduced on the CL-601-1A. Canadair CC-144 Twelve aircraft were purchased by the Royal Canadian Air Force and delivered in 1982, including the CE-144 and CX-144. A further seven airframes have been procured from 1982 through 2020. Models CL-600, CL-601, CL-604, and CL-650 have all been procured to fill the role. Canadair CE-144 Three electronic warfare (EW) trainers were converted to/from basic CC-144. Canadair CX-144 Second prototype, a CL-600-1A11, c/n 1002, was allocated to the RCAF after finishing its test programme. Used at the Aerospace Engineering and Test Establishment (AETE), CFB Cold Lake until retirement in 1993, it is now preserved at the CFB Winnipeg, designated CC-144 in service. Challenger 601 (CL-600-2A12) CL-601-1A A refined version, it included winglets to decrease drag and add more powerful General Electric CF34-1A (66 built, including six Canadian Forces CC-144Bs) CL-601-1A/ER 601-1A retrofitted with an additional fuel tank in the tail Challenger 601-3A/3R (CL-600-2B16) CL-601-3A (2B16) GE CF34-3A engines with a higher flat rating and a glass cockpit: This was the first version marketed by Bombardier. CL-601-3A/ER 601-3A with an additional, optional fuel tank in the tail CL-601-3R The tail tank was made standard, and CF34-3A1 engines were introduced. CL-601s Version powered by GE CF34-3A2 engines Challenger 604/605/650 Advanced GE CF34-3B engines;