Stall

As experts struggle to identify why the crew of Air France 447 lost control of their A330 over the South Atlantic Ocean nearly four years ago, the industry is also still struggling to develop the precision data needed to accurately reproduce a stall in a Level D simulator. The lack of accurate stall data limits entry and recovery practice because the computers running the simulators have no idea how the aircraft will actually perform.

The FAA recently published a notice to operators, training managers and inspectors of the importance of AC 120-109, to reinforce the importance of adequate flight crew training on the use of aircraft stick shakers and pushers. The increased emphasis was the result of a September 2010 Aviation Rulemaking Committee (ARC) to stem the numbers of loss-of-control accidents due to pilot unfamiliarity with stick pushers, as well as flight into icing and wind-shear conditions.

At a time when aviation has achieved an extraordinarily high level of safety, regulators and safety organizations are pushing for more improvements in pilot training to preempt future accidents and ensure that new pilots entering the ranks start off with the right approach. One of the key areas receiving extensive examination is stall training, both in the early stages of ab initio training and how it is taught later to pilots who are flying sophisticated high-performance jets.

The NTSB has blamed the April 2, 2011, flight-test crash of a Gulfstream G650 on an aerodynamic stall and an uncommanded rolling moment that the pilots were unable to control. However, the Board also notes that it was the manufacturer’s rush to complete its aggressive flight-test schedule for obtaining certification that set the stage for the stall and uncontrollable roll.