Boeing had a brief spell of good news during which the International Airlines Group agreed to purchase an unknown number of Boeing’s 737 MAX 8 aircraft. However, as we mentioned; it was brief. We say this because a new flaw in the 737 MAX 8 computer system has popped up which is unrelated to the MCAS but yet capable of sending the plane into a nosedive within a matter of seconds that might prove to be unrecoverable.
Sources that are at the heart of the effort for recertification of the 737 MAX 8 have also confirmed that a flight simulator testing has shed light on an altogether different way that might cause the plane to pitch down. According to these sources, this particular nosedive would prove to be harder for a pilot to handle during an emergency as opposed to the nosedive that is caused by the MCAS system. The newly found flaw is related to a microprocessor failure in the 737 MAX 8 computer system and can cause – what is known in the industry as – runaway stabilizer trim.
For those of you who are unaware, the stabilizer is the name given to the smaller and horizontal wings located on the tail of the aircraft that generally stabilize the aircraft in flight. Depending upon the angle of attack, they can cause the tail upward or push it down relative to the rest of the plane. If the upward or downward push is too far in any direction, it is given the name of the runaway. This is the marking of the point where a pilot is supposed to cease power to the stabilizer by making use of a wheeled lever in the cockpit. This rectifies the stabilizer and brings it to the normal and forward-facing angle.
The mechanism is incorporated into the heart of the MCAS anti-stall system whose malfunction has been undergoing investigation following the crashes of Lion Air Flight 610 and Ethiopian Airlines Flight 302. The latest microprocessor flaw has been brought to light when government pilots were busy working with the Federal Aviation Administration (FAA). The team tested to gauge the effects of a microprocessor failure in the 737 MAX 8’s computer. Pilots learned that during these tests if the microprocessor failed, the plane would begin pitching forward and would go into a nosedive that would be unrecoverable unless intervened quick enough.
According to the source, ‘It was difficult for the test pilots to recover in a matter of seconds. And if you can’t recover in a matter of seconds, that’s an unreasonable risk.’ The FAA has still not confirmed the exact issue but has stated that the ‘FAA’s process is designed to discover and highlight potential risks. The FAA recently found a potential risk that Boeing is required to mitigate.’
According to a statement released by Boeing, ‘The safety of our airplanes is Boeing’s highest priority. During the FAA’s review of the 737 MAX software update and recent simulator sessions, the Federal Aviation Administration (FAA) identified an additional requirement that it had asked the company to address through the software changes that the company has been developing for the past eight months. The FAA review and process for returning the 737 MAX to passenger service are designed to result in a thorough and comprehensive assessment. Boeing agrees with the FAA’s decision and request and is working on the required software. Addressing this condition will reduce pilot workload by accounting for a potential source of uncommanded stabilizer motion. Boeing will not offer the 737 MAX for certification by the FAA until we have satisfied all requirements for certification of the MAX and its safe return to service.’