BOEING HAS added a third 737 MAX 10 to its flight test programme as it ramps up efforts to secure certification for the type. The aircraft, N27753 (c/n 66118), undertook its maiden flight from Renton Municipal Airport, Washington, on November 18, wearing the livery of launch customer United Airlines. It joins testbeds N27751 (c/n 66122) and N27752 (c/n 66123), but its arrival is unlikely to help the US manufacturer meet a crucial end-of-year deadline for type approval.