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“I can tell you my family and your family will be safe on this aircraft,” FAA Administrator Steve Dickson said on the approval to 737MAX to return to skies again after being grounded for 20 months.
FAA cleared 737MAX to return to service after reviewing, testing, and analysing documentation process on upgraded MCAS software, which caused two fatal crashes that killed more than 320 people.
The 737MAX crisis clearly shattered Boeing’s reputation for engineering excellence, question Boeing’s design, marketing and testing of any plane.
It also damaged FAA’s credibility as the world’s arbiter of aviation safety.
Boeing 737MAX timeline
2011 – Boeing rushed to launched 737MAX, an update of 40 year old 737 before the huge order from American Airlines to be snapped by Airbus A320neo.
Boeing added new larger powerful engine, which forced the aircraft to always tend fly in nose pitch up position. To counteract, Boeing added a software called MCAS Maneuvering Characteristics Augmentation System flight control law.
MCAS adjusts the horizontal stabilizer trim to push the nose down when the aircraft is operating in manual flight, with flaps up, at an elevated angle of attack (AoA), so the pilot will not inadvertently pull the airplane up too steeply, potentially causing a stall.
2015 – First MAX plane rolled out of Boeing’s Renton factory.
2017 – Federal Aviation Administration of the United States certifies the MAX
29 Oct, 2018 – The Lion Air 737MAX crashes shortly after takeoff in Indonesia, killing all 189 people onboard
6 Nov, 2018 – Boeing issues a service bulletin to all operators of 737MAX-8/9 warning Angle of Attack sensor can cause erroneous indication causing the aircraft to nose dive
10 March 2019 – Ethiopian Airlines Boeing 737MAX crashes soon after departure killing all 157 people onboard.
13 March 2019 – Aviation Regulators ground the MAX worldwide
27 March 2019 – Boeing outlines the MCAS software fix that may have cause the planes to crash.
29 April 2019 – Boeing’s then CEO Denis Muilenburg denies any flaws on the design of MCAS
25 Oct 2019 – Final investigation report into Lion Air crash pointed the design fault on MCAS
23 Dec 2019 – As pressure around the world mounted against the way Boeing handled the crisis, Boeing fired CEO Denis Muilenburg
7 April 2020 – Boeing revered from its defensive position and said pilots require additional training to fly MAX
3 Aug 2020 – FAA finalises, Boeing’s updated MCAS fixes, training outline and requirements to return to service
18 Nov 2020 – FAA cleared the 737MAX to return to service after 20 months of grounding.
The updated version:
The Maneuvering Characteristics Augmentation System (MCAS) flight control law was designed and certified for the 737 MAX to enhance the pitch stability of the airplane – so that it feels and flies like other 737s.
MCAS is designed to activate in manual flight, with the airplane’s flaps up, at an elevated Angle of Attack (AOA).
Boeing developed an MCAS software update to provide additional layers of protection if the AOA sensors provide erroneous data.
The software is validated during in-flight certification tests with Federal Aviation Administration (FAA) representatives.
The additional layers of protection include:
Flight control system will now compare inputs from both AOA sensors. If the sensors disagree by 5.5 degrees or more with the flaps retracted, MCAS will not activate. An indicator on the flight deck display will alert the pilots.
If MCAS is activated in non-normal conditions, it will only provide one input for each elevated AOA event. There are no known or envisioned failure conditions where MCAS will provide multiple inputs.
MCAS can never command more stabilizer input than can be counteracted by the flight crew pulling back on the column. The pilots will continue to always have the ability to override MCAS and manually control the airplane.
These updates are accepted by the FAA and now is ready to fly again!
Now Boeing has an immense task of dispatching more than 800 parked aircraft, and find new customers to more than 60 aircraft which has been cancelled.