DATA: should Lion Air responded to prior events?
DATA: should Boeing have tracked MCAS by ACRS
Although the National Transport Safety Committee (KNKT) has issued a preliminary report, which has generated much controversy, it is premature to even begin to discuss the “probable cause” of the Lion Air JT 610 Boeing 737 MAX crash.
However, the future of aviation safety relies heavily on technology to reduce risk and it is appropriate to begin discussing the implications of this tragedy. This review should consider two dimensions:
the Maneuvering Characteristics Augmentation System is designed to address the potential for stalling
Lion Air Data Points
Management has an affirmative duty to constantly monitor and evaluate its operations. According to the KNKT:
“But investigators said that Lion Air kept putting the plane back into service despite repeatedly failing to fix a problem with the airspeed indicator in the days leading up to the fatal flight.
Its second last flight was from Denpasar in Bali to Jakarta.
‘During (that) flight, the plane was experiencing a technical problem but the pilot decided to continue,’ Nurcahyo Utomo, aviation head at the National Transport Safety Committee, told reporters.
‘The plane was no longer airworthy and it should not have kept flying,’ he added.”
Indeed, the pilots in the Lion Air crash didn’t follow an emergency procedure that could have deactivated MCAS and allowed them to fly normally, according to investigators. A different pilot crew the night before the accident had effectively shut off MCAS during an identical emergency and landed routinely.
The “angle of attack” sensors on the plane had been replaced the day before the fatal flight, The Associated Press reported. Additionally, airspeed indicators malfunctioned on the three flights leading up to Monday’s crash, as well as during the last flight, Indonesian investigators have said.
The point is not whether the aircraft was “airworthy” or not, but what threshold of data points should have compelled Lion Air to stop and determine how this reoccurring failure of the AOA system can be stopped. Perhaps by referring to the FAA Aviation Safety Information Analysis and Sharing or Flight Safety Foundation’s Global Information Sharing Systems, management might have learned more about the issue and gained some insight as to a solution.
From a learning standpoint, obviously management did not consider these events to be significant risks; why not? ASIAS and GAIN were available tools; were they not aware of these safety information systems? From these and other questions, can procedures or standards be established to help future similar situations. The SMS principle of self-disclosure supports the value of assessing human errors to prevent future repeating.
MCAS and ACRS
Why is there an MCAS?
What MCAS does:
“the MCAS (Maneuvering Characteristics Augmentation System) is implemented on the 737 MAX to enhance pitch characteristics with flaps UP and at elevated angles of attack. The MCAS function commands nose down stabilizer to enhance pitch characteristics during steep turns with elevated load factors and during flaps up flight at airspeeds approaching stall. MCAS is activated without pilot input and only operates in manual, flaps up flight. The system is designed to allow the flight crew to use column trim switch or stabilizer aisle stand cutout switches to override MCAS input. The function is commanded by the Flight Control computer using input data from sensors and other airplane systems.
MCAS is a system designed to address a new, specific flight situation. Though the B-737 MAX met all of the Part 25 certification tests, might Boeing have considered linking this unique instrument with an Aircraft Communications, Addressing and Reporting System (ACARS) connection? ACARS already provides a continuous meter of a number of onboard systems. With a fleet of this top selling aircraft, the OEM would have received early indications that the pilot use/understanding was a challenge. If such an automated system is too too difficult to connect, perhaps just providing greater oversight might have been justified. New systems do not always perform in the real world as expected; maybe ACARS might be attached to the initial units of the innovative equipment? The macro data available to Boeing might be a basis for finding proactive solutions.
The 737 MAX is an extremely important addition to the global fleet. MCAS is not the only technology advance included in this aircraft. Both the operator and the OEM should have been sensitive to detecting small data points in the early flights of this plane. Technology both allows such microscopic attention and is contributing to the MAX’s future.
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