The Weekly Reflektion 29/2022

17. July 2022

The aircraft industry is highly competitive and a key factor for commercial airlines is fuel efficiency. Reducing operating costs will lead to lower fares and more customers. The customers also expect that safety standards will not be compromised in the drive to cut costs.

Are you able to maintain and improve your safety standards through periods of turbulence and change?

In 2010 Airbus announced a plan to upgrade their A320 single-aisle aircraft, at that time the most popular aircraft in the Airbus fleet. The main element in the upgrade was a new geared turbo-fan engine. The engine was physically much larger and wider than the standard engine, however it was 15 percent more fuel efficient. The upgrade was not considered a significant change to the existing A320 so the pilots could fly the new version with little additional training. The A320 NEO would save the airlines a lot of money without simulatortraining or significant familiarisation costs for the aircrew.

The A320 NEO created a problem for Airbus rival Boeing. Boeing recognized the competitive advantage of the NEO and started work on a similar upgrade to the Boeing 737. There was however one essential difference between the two aircraft, the 737 had less ground clearance than the A320. WhereasAirbus could easily hang the new engines in the same place on the A320 wings, there was not enough room under the 737 wing. The Boeing developers soon ‘solved’ this problem by moving the engine to a location higher on the wing. The top of the engine ended up above the top of the wing. Boeing called the new plane the 737 MAX. Like Airbus, Boeing claimed the new version of the 737 was similar the current versions henceonly minimal additional training was required for the pilots.

In 2011 Airbus sold 1226 A320 NEO aircraft significantly outperforming Boeing with only 150 sales of the 737 MAX. In 2012 however the 737 MAX became the hottest selling plane on the market and 914 were sold compared to 478 for the Airbus A320 NEO. Boeing seemed to have re-established their market share.

The modification of the engine location on the 737 affected the aircraft aerodynamics. When the 737 MAX was in full thrust, for example during take-off, the nose tended to point too high that could lead to a stall. This was a problem since the aircraft was supposed to behave exactly like the earlier versions. Boeing solved that with a ‘workaround’. Instead of re-engineering the aircraft they installed software that automatically pushed the nose downwards by pivoting the rear stabilisers to push the nose down. The system was called the ‘Manoeuvring Characteristics Augmentation System (MCAS). However, since the new aircraft was claimed to be essentially the same as previous versions Boeing did not highlight the new MCAS system. Pilots only received a 2-hour training course before they were ready to fly, and neither the course nor the training manual mentioned or described the MCAS system. During 2018 several pilots in the USA complained to the Federal Aviation Authority (FAA) about the 737 MAX suddenly ‘nosing down’. On October 29, 2018, Lion Air Flight 610 crashed due to a problem with the MCAS. On March 10, 2019, Ethiopian Airways Flight 302 also crashed due to problems with the MCAS. Next week we will continue the 737 MAX story.