Lion Air Crash Leads to Dispute Over Automated Control System
The dispute between Lion Air and Boeing over the crash of a 737 Max 8 jetliner in October is intensifying, and Lion Air may attempt to cancel some of the 190-odd aircraft it has on order from the Chicago-based aerospace company. The circumstances leading up to the crash - and the ensuing disagreement - center on the design of automated navigation systems and the decisionmaking role of human operators.
The new 737 Max 8 aircraft that went down off Jakarta was fitted with a proprietary anti-stall system called the "maneuvering characteristics augmentation system" (MCAS). Even in manual flight mode, MCAS can automatically move the aircraft's stabilizers to angle the plane downwards when it assesses that the nose is pointing too high. The system uses information from sensors that indicate the aircraft's orientation, and its operation is fully independent of the pilot's judgement.
According to an emergency post-accident bulletin from the U.S. Federal Aviation Administration, MCAS can give repeated nose-down commands to the aircraft's stabilizers if it receives inaccurate, high input from a single angle of attack sensor. "This condition, if not addressed, could cause the flight crew to have difficulty controlling the airplane, and lead to excessive nose-down attitude, significant altitude loss, and possible impact with terrain," FAA wrote. The agency required Boeing to update the aircraft's operating manual with more information on how to disable MCAS in the event of a "runaway" stabilizer trim event.
Marine salvors recovered the aircraft's black box from the crash site, and the data they retrieved showed that the pilots fought repeatedly to bring the aircraft's nose up. The plane pitched down 26 times in 11 minutes, and in the final moments of the flight, one pilot was exerting nearly 100 pounds of force on the control column in an attempt to pull up.
In late November, Indonesian investigators reached a preliminary conclusion that the pilots were attempting to fight trim-down instructions issued by the MCAS system. It is believed the flight crew did not implement the sequence of manual overrides required to shut down MCAS.
Lion Air alleges that Boeing did not include full information on the procedure to disable the system in its training manual for the new Max 8, a charge which Boeing denies. "We don't have that in the manual of the Boeing 737 MAX 8. That's why we don't have the special training for that specific situation," alleged Zwingli Silalahi, Lion Air's operational director. "We didn't receive any information from Boeing or from regulator about that additional training for our pilots."
Lion Air has its own history of safety issues, and the specific plane involved in the crash had experienced similar problems on three previous flights. An angle of attack sensor was replaced by ground crews the day prior to the accident, but problems continued on the second-to-last flight.
The search continues for the aircraft's cockpit voice recorder (CVR), which may hold valuable clues about the aircraft's final minutes. Salvors may have difficulty finding this second black box, however, as officials believe that it may be buried in the mud of the seafloor.
The crash comes as aircraft regulators, manufacturers and operators are contemplating a future with single-pilot - or even fully autonomous - cargo jet aircraft. The possibility of reduced manning in the cockpit is concerning for pilots' unions, but in a close parallel to the discussion of autonomous shipping in the maritime industry, it offers interesting possibilities to cut staffing costs for air cargo companies.
“How do we maintain levels of safety that we enjoy today . . . when you’ve got an artificial intelligence-based system in the cockpit?” said Boeing CTO Greg Hyslop at a conference in September. “How do you show and certify that to be safe to the point where the flying public would say, ‘Yes, I trust that.’" While the autonomous passenger aircraft may be far off, Hyslop said, "clearly, for transporting cargo, you could see autonomous aircraft."