Second JF-17B prototype now flying

Photos emerged of the second prototype of the JF-17 Thunder’s twin-seat variant – designated JF-17B – undergoing flight tests in China.

Although the Pakistan Air Force (PAF) was comfortable training JF-17 aircrews using simulators, potential third-party customers had requested a twin-seat variant for training and evaluation purposes. Production of the first JF-17B prototype began in April 2016, with the aircraft conducting its first flight a year later.

Three JF-17B prototypes are under production, two of which will join the PAF.

Notes & Comments:

In addition to a tandem seat, the JF-17B incorporates several design changes to its single-seat counterpart. These include a modified vertical stabilizer, dorsal spine (potentially for fuel to compensate for the space lost from the additional seat), enlarged nose and three-axis fly-by-wire (FBW) flight control system.

An alleged brochure from the Aviation Industry Corporation of China (AVIC) claims that the JF-17B also has a longer wingspan (by 0.5 m), potentially indicating a lower wing-loading for reduced take-off distance and increased maneuverability. The JF-17B also has a different materials proportion to the single-seat JF-17, which might indicate greater composite usage.

Given the extensiveness of structural changes (in addition to the second seat) on the JF-17B, the JF-17B’s relationship to the JF-17 Block-III will be worth observing. For example, among the JF-17 Block-III’s changes is three-axis FBW supplanting the Thunder’s existing hybrid flight control system (which has mechanical controls of bank and yaw, while electronic for pitch).

To bridge the gap between the 50^th JF-17 Block-II and the JF-17 Block-III, the PAF has ordered an additional 12 JF-17 Block-II (Arabian Aerospace). Although the current PAF Chief of Air Staff (CAS) hinted at using the JF-17B for a lead-in fighter-trainer (LIFT) role, it is unclear if the PAF will order the JF-17B in numbers.

The JF-17 has replaced most of the PAF’s Chengdu F-7P units. Interestingly, the remaining F-7P/FT-7P unit is the No. 18 operational conversion unit (OCU). The PAF has the option of transitioning the No. 18 OCU to a mixed JF-17 Block-II and JF-17B fleet, enabling No. 18 to provide OCU for the No. 16, 26, 02 and 14.