|CL-601-1A is a refined version including winglets to reduce drag and more powerful General Electric CF-34 engines. (66 built), The CL-601-1A/ER: 601-1A retrofitted with an additional fuel tank in the tail. The CL-601-3A upgrade an engine 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 and with the CL-601-3R: the tail tank was made standard, and airline style "unsided" engines (no left or right) were used, matching what was used on the CRJ.