Investigations into the Lion Air Boeing 737 Max ­tragedy last month are examining any role that a new automated stability system may have played.

The Max is the first 737 to be equipped with the Maneuvring Characteristics Augmentation System. This is a form of “flight-envelope protection” that automatically counters certain handling “characteristics” caused by design changes on the 737 Max. Specifically, this is a pitch-up in certain configurations as a result of the more powerful and repositioned engines.

Crucially, the existence of the new Max system and its functions had apparently not been included in the conversion syllabus for pilots, many of whom fly the new variant alongside earlier 737s.

Back in the 1960s, an automatic pitch-control system was introduced to counter a flying characteristic caused by a design attribute. These were the “stick-pusher”, deep stall and T-tail configuration, respectively. Like MCAS, the stick-pusher triggers in manual flight. And like the MCAS, it could malfunction. But unlike MCAS – until now – crews were well aware of its existence and trained to deal with malfunctions.

In a world where cross-qualification is the accepted norm, the industry has had a stark reminder of how decisions about the training syllabus for operating similar, but not identical designs can be safety-of-flight critical. ­Manufacturers and certification authorities – take note.

Source: Flight International