In Test of Boeing Jet, Pilots Had 40 Seconds to Fix Error


One of the people involved in the training said MCAS was surprisingly powerful once tested in the simulator. Another person found the system controllable because it was expected. Before the Lion Air crash, Boeing and regulators agreed that pilots didn’t need to be alerted to the new system, and training was minimal.

At least some of the simulator flights happened on Saturday in Renton, Wash., where the 737 Max is built. Pilots from five airlines — American, United, Southwest, Copa and Fly Dubai — took turns testing how the Max would have responded with the software running as it was originally written, and with the updated version, known as 12.1.

In the simulations running the updated software, MCAS engaged, though less aggressively and persistently, and the pilots were also able to control the planes.

Boeing’s software update would require the system to rely on two sensors, rather than just one, and would not be triggered if the sensors disagreed by a certain amount, according to the three people. Given that the 737 Max has had both sensors already, many pilots and safety officials have questioned why the system was designed to rely on a single sensor, creating, in effect, one point of failure.

The update would also limit the system to engaging just once in most cases. And it would prevent the system from pushing the plane’s nose down more than a pilot could counteract by pulling up on the controls, the three people said.

In conversations with pilots and airline officials over the weekend, Boeing executives didn’t directly address why MCAS was designed with such flaws, one person with direct knowledge of the meetings said. Instead, the company stayed focused on the software updated, the person said.

The software changes still require approval by the Federal Aviation Administration. Pilots’ unions have said they are comfortable with the proposed changes but want to review them before making a decision. Pilots will be required to complete a training on the updated system on their iPads.

Source : Nytimes