MCAS: A software that contributed in two plane crashes.
On October 29, 2018, A Lion Air flight 610 with registration PK-LQP crashed into the Java Sea shortly after takeoff from Jakarta, Indonesia on a scheduled flight to Pangkal Pinang, Indonesia. All 189 passengers and crew aboard died in crash. On March 10, 2019, A Ethiopian Airlines flight with registration ET-AVJ crashed after takeoff from Addis Abada, Ethiopia on a scheduled flight 302 to Nairobi, Kenya. The crash killed all 149 passengers and 8 crew members aboard. Both crashes involved a similar type of aircraft, a Boeing 737max family of aircraft, specifically a 737 Max 8. The 737max family of aircraft were a new single-aisle family of aircraft for airplane manufacturer Boeing. These two crashes caused world wide grounding of 737max aircraft around by Aviation Regulators of various countries including FAA (Federal Aviation Administration).
For understanding the relation between MCAS software and 737max crashes, we’ve to look at competition between aircraft manufacturers Boeing and Airbus.
Why was the Boeing 737Max created?
The aircraft industry is dominated mainly by two companies, Airbus and Boeing. Both are always in a race to make a better plane than each other. In 2010, Airbus updated their single-aisle aircraft, the Airbus A320 by adding an higher bypass turbo fan engine which had larger diameter than previous generation in an effort to improve fuel efficiency by 15%. Airbus named it Airbus A320neo with neo meaning ‘New Engine Option’. With Airbus updating their single-aisle aircraft, Boeing could’ve lost lot of revenue and market share if the didn’t reacted. So, Boeing decided to update their single-aisle aircraft, the 737. But their was a problem. As shown in image below, 737 is much lower to the ground compared to its competitor, the A320. Hence, Airbus was easily able to accommodate a larger, fuel-efficient engine under its wing. For Boeing, it was not possible.
Hence, Boeing placed the engine above the wing to solve this issue as shown below. Boeing named their new aircraft as Boeing 737max. Boeing claimed to airlines that earlier 737 pilots can fly the new plane with minimal training. This marketing strategy was done since training of pilots for a new aircraft generally requires a lot time and money for the airlines. However, we all know that all was not going to be smooth sailing for Boeing in coming months.
How MCAS was incorporated in 737Max?
Due to the unusual positioning of new high-bypass turbo fan engines, during some situations with airplane at full thrust such as takeoff, the nose of airplane tend to point upwards. If not dealt by pilots, it could’ve stalled the aircraft due to the loss of lift at wings, resulting in an accident. To deal with it, Boeing incorporated MCAS (Moving Characteristics Augmentation System). This software that was incorporated in the flight computers of the aircraft which helped fly the plane. Its function was to push down the nose of the aircraft when it was going too high like during takeoff situations. This system was created to curb the problem of nose of the 737max aircraft pointing upwards in high thrust situations. This was done since Boeing wanted that earlier 737 pilots can transition to the 737max aircraft without any additional training. However, it rather caused major problems for the American aircraft manufacturer.
How MCAS contributed in the two crashes?
According to preliminary report into Lion Air crash, one of the sensors namely pitot tube was sending wrong information to MCAS and flight computers which made system to believe that aircraft’s nose was pointing too high and was about to stall. This made plane’s MCAS to push the nose of the plane down until the pilots lost the control of the aircraft and crashed. In Ethiopian Airlines crash, pilots were able to disable the MCAS, however it was too late. A system designed to save lives on an aircraft rather contributed in two deadly crashes.
Boeing’s marketing strategy played key role in these crashes as well. Due to Boeing’s promise of minimal training for new aircraft, many pilots only had a two hour iPad session before jumping into the cockpits of these 737max aircraft. What’s even more surprising is that, in the two hour iPad session, there was no mention of the MCAS system. Many American Pilots complained about sudden nose diving of the 737max aircraft to FAA even before the two crashes.
Outlook of the whole situation
After the two crashes, all 737max aircraft were grounded all over the world. Boeing was told to reconfigure the MCAS system aboard their 737max and test it. At the time of writing of this article, the grounding of 737 is still going on and deliveries of the aircraft have been halted. Boeing is still working a fix for their MCAS system. In US, FAA regulator also came under heavy scrutiny for certifying a faulty aircraft.
This situation shows how in race to overhaul their competitor Airbus and rushing their 737max product caused so much problems. Also shows how incorrect inputs to the systems can cause so much problems. Also shows how software and systems aboard the aircraft are important for the safety of passengers and crew aboard the aircraft, how thoroughly these systems should be tested and should involve human correction. With just one faulty sensor, the whole flight computer was fooled. Industry would learn lessons from these crashes, however for friends and families of those 346 killed in these two crashes, it is too late.
