This at first seems to be a (relatively) unremarkable picture. However, this was taken during a program by Nasa Dryden to develop a system for aircraft control in the event of control surface failure. The concept is to use differential engine thrust to maneuver the aircraft, known appropriately as the Propulsion-Controlled Aircraft (PCA) system. This feat is made more impressive given the testbed.
The aircraft itself is the McDonnell Douglas MD-11, which has an interesting history itself. The design is a modified DC-10, note the center landing gear which was added to the design as part of range-increasing modifications implemented during later manufacturing blocks. The MD-11 is also reportedly difficult to land, as the CG was moved backward (making the aircraft less stable) and the tail area decreased as compared to the DC-10. This combination has perhaps contributed to the three incidents of flip-over during hard landings of MD-11 aircraft, a black mark not matched by any other type.












