The AW139 is a conventional twin-engine multi-role helicopter. It has a five-bladed fully articulated main rotor with a titanium hub and composite blades and a four-bladed articulated tail rotor. It is fitted with retractable tricycle landing gear, the two aft wheels retracting into external sponsons which are also used to house emergency equipment. It is flown by a crew of two pilots, with up to 15 passengers accommodated in three rows of five. The AW139 had been aimed at a vacant niche in the market, sitting below larger types such as the Eurocopter AS332 Super Puma and Sikorsky S-92, and above smaller ones like the Bell 412 and Eurocopter EC155. Rotor & Wing has described the AW139’s flying attitude as ‘docile and predictable’.
The AW139 is powered by two FADEC-controlled Pratt & Whitney Canada PT6C turboshaft engines; the FADEC system seamlessly adjusts the engines for pilot convenience and passenger comfort, and can automatically handle a single-engine failure without noticeable deviation. It was constructed with maintenance requirements in mind; critical systems can be readily accessed, where possible the number of parts has been reduced, and many components have been designed for an extended lifecycle; a Health and Usage Monitoring System (HUMS) is also equipped. More than a thousand customizable items of equipment can be configured per customer demand, including auxiliary fuel tanks, rescue hoists, cargo hooks, search and weather radar, ice protection systems, external cameras and searchlights, and seating arrangements.