Written by: Ollie Watts

Alongside Europe-based Airbus, American heavyweight Boeing is at the forefront of commercial airliner production, with over 10,000 aircraft in service worldwide. Over the decades it has blessed the global airline market with several game-changing aircraft, from the Boeing 747 ‘Jumbo Jet’ in 1970 to the Boeing 787 ‘Dreamliner’ in 2011. Lest not forget the Boeing 737, which, since launching in 1968, has been redeveloped several times. Its latest model, the Boeing 737 MAX, is now Boeing’s best selling aircraft with over 5000 orders. However, last week’s fatal crash of an Ethiopian Airlines 737 MAX 8 has resurfaced a lethal technical flaw that could see Boeing’s fortunes dwindle. The world’s Boeing 737 MAX fleet has now been grounded until this has been addressed.

What is the Boeing 737 MAX?

In a nutshell it is Boeing’s latest flagship product. The Boeing 737 is not an altogether new aircraft, but has simply been redeveloped into different models since 1968. Like mobile phones and game consoles, airliners are also relaunched over time into different models to take advantage of the latest technology. The Boeing 737 MAX is the latest model of the 737, with its predecessor being the Boeing 737 NG; a very popular short-haul aircraft whose major operators include Ryanair. The 737 NG has several variants and Ryanair operates the 737-800 variant, for example. The 737 MAX has a 7, 8, and 9 variant. It boasts 14% greater fuel efficiency than the 737 NG, larger and quieter engines, and a new winglet design. As the 737 NG is now ageing technology, the 737 MAX offers an up to date model showcasing the some of the very latest aeronautical developments. With increased range and fuel efficiency, it even allows trans-Atlantic and trans-continental operations that some airlines have decided to capitalise on. The best example of this is low cost carrier Norwegian, who fly some of their 18 737 MAX 8s from Ireland to regional destinations on the US East coast such as Stewart and Providence.

Why has it been grounded?

The Ethiopian Airlines crash is the second 737 MAX 8 crash to occur in 5 months, the first was of a Lion Air 737 MAX 8 in Indonesia in October 2018. Both crashes killed all on board, and both happened within 10 minutes of takeoff. Though the investigations are still in progress, initial observations suggest that a flight system unique to the 737 MAX is malfunctioning, with, in these cases, fatal consequences. Known as ‘MCAS’, the system detects when the aircraft is climbing too steep. The MCAS was introduced because the 737 MAX engines are bigger, and therefore positioned further forward on the wing, which creates a pitch-up tendency when the aircraft ifs climbing. Overtly-steep climbing increases the risk of the aircraft losing too much speed and stalling. To counteract this, if the MCAS detects that the climb is too steep, it will make the aircraft nose pitch down at an appropriate rate to recover the situation, and the pilots can take over if they wish. However, if it malfunctions, it will nosedive and fail to respond to the pilot’s input. The lethal consequence is the aircraft cannot be recovered from the nosedive, resulting in a crash. From initial flight data evidence, and there is still much to be analysed, it suggests the Ethiopian and Lion Air 737 MAXs nosedived to the ground and the pilots could not regain control. 

To add some wider context to this technical point, an aircraft’s autopilot can be disengaged by the pilots at any point through pushing a button on the flight controls. Thus, if the autopilot was engaged on a 737 MAX when the MCAS pushed the nose down steeply, the pilot should in theory be able to recover this by disengaging the autopilot and taking manual control. If the MCAS malfunctions, this course of action will have no effect and the aircraft is in a free fall. If the autopilot is not engaged and MCAS malfunctions, the result is the same.

Asian airlines were the first to ground the 737 MAX, followed by European and US airlines. On 14th March 2019, Boeing officially grounded the 737 MAX globally and it is not currently permitted in any airspace. Until the software for the MCAS is updated and tested, the aircraft will remain grounded for ‘months’ reports the US FAA (Federal Aviation Administration).

Is Boeing in a lot of trouble?

Aviation is a heavily regulated industry, so Boeing will be certain to face reprimand. The most alarming issue to surface in the wake of the Ethiopian crash is Boeing did not issue information about the MCAS to airlines who operate and are due to operate the 737 MAX. Airlines training its pilots to fly the 737 MAX were unaware about it. Aside from some airframe, flight deck, and software changes such as MCAS, the Boeing 737 NG and 737 MAX are very similar. Many 737 MAX pilots are previous 737 NG pilots, and it appears Boeing were complacent on this point and felt MCAS was a minor operational difference. Whether Boeing intentionally withheld the information on MCAS is another matter entirely, but if ever proven, could see them face criminal legal action, and several civil claims. Indeed this potential cover up evokes memory of the NASA Space Challenger disaster in 1986, where NASA authorised the launch despite prior knowledge of errors with the booster rockets.

“I am left to wonder: what else don’t I know? The flight manual is inadequate and almost criminally insufficient. All airlines that operate the Max must insist that Boeing incorporate ALL systems in their manuals” – anonymous 737 MAX pilot (Business Insider)

In regard to the anonymous pilot’s comments above, the US FAA and its worldwide counterparts issue airworthiness directives to airlines regarding known technical/safety deficiencies with aircraft types. It brings issues to the attention of the airlines who can then address them through pilot training, aircraft maintenance and cooperation with the manufacturer. The FAA issued an airworthiness directive after the Lion Air 737 MAX crash which touched on the high angle of attack issue, but did not specifically address the malfunctioning MCAS system.

As noted earlier, Boeing has over 5000 orders for the 737 MAX, and the company is the USA’s largest single exporter. It has a place on the NYSE, and the Ethiopian crash saw its shares drop between 4.6-12% in the past week. Its market capitalisation has also dropped sharply, wiping off $226 billion. The software fix to the MCAS system is expected to ground the aircraft until May, which is when the summer season starts for many airlines.

How are airlines affected?

The primary issue for airlines who operate the 737 MAX is potential aircraft shortages, which they will need to address by chartering aircraft from lessors. This is expensive, and leased aircraft are often older, less fuel efficient types, which results in higher fuel costs. TUI Airways is the only UK airline operating the 737 MAX, with 6 in its fleet. It has confirmed it will be chartering aircraft from lessors. Norwegian has publicly stated it will bill Boeing personally for the costs incurred by having to ground its 18 737 MAXs. It has utilized one of its Boeing 787s to fly the trans-Atlantic schedule from Ireland for the meantime, which is usually operated by a 737 MAX. The larger the 737 MAX fleet an airline has, the bigger the burden on them, such as Southwest Airlines in the USA who has 34. Their shares dropped 2.6% as a result of the grounding. The issue also threatens consumer confidence in airlines operating the aircraft, as even when the issue is fixed, it will take a lot to convince their customers they are safe flying on a 737 MAX.


The 737 MAX flaw has put enormous pressure on Boeing. It needs to fix the MCAS issue, which could take months, and they will likely be losing money doing so. Its shares may keep dropping. Money, however, needs to come secondary, as if it does not get the fix right, the long term-implications could be cataclysmic. Safety is of paramount importance, and Boeing’s response will determine its future for some time. If it is not careful in how it handles the crisis, then many airlines will surely drop Boeing for rival Airbus, whose A320/A321 NEO is increasingly popular. The world’s airlines and flying population await Boeing’s response.