Challenge Group has launched its Boeing 777-300ERSF conversion programme, and stated there could be up to 10 of the conversion type in its fleet within the next five years. Challenge has already transferred the first aircraft in its conversion programme to IAI’s facilities for modification, said reports. The company anticipates converting three more aircraft and has options for an additional four. This follows the announcement by Challenge in January that it had signed a deal with lessor AerCap to add two Boeing 777-300ERSF freighters converted by Israel Aerospace Industries (IAI) to its fleet. In total, this means Challenge could eventually operate as many as 10 777-300ERSFs. Each 777-300ERSF has a payload capacity of nearly 100 tons.