WITH an average of 5,500 aeroplanes landing and departing within Britain every day, short- and long-haul aeroplane journeys have become commonplace since the first scheduled commercial flight in 1914. Although the principles of flight may seem mystifying, aeroplanes today rely on simple fundamentals of aerodynamics — just as they did a hundred years ago.
 
The four forces that act on an aeroplane are lift, weight, thrust and drag. We can understand their interplay using Isaac Newton’s three laws of motion, formulated in the 17th century.

Thrust is generated by the engines of an aeroplane, acting forwards. Newton’s third law of motion states that every action (or force) has an equal and opposite reaction (force in the opposing direction).

The opposing force to thrust is drag, acting backwards. Drag arises from the aeroplane moving through the air (think about when you try to move through a strong wind and feel the resistance from the air pushing on you).

If thrust and drag balance each other out, the aeroplane will either remain stationary or continue to move at a constant velocity — this is Newton’s first law of motion in action. For an aeroplane to accelerate, the thrust from the engines must be greater than the drag from airflow, and this is Newton’s second law of motion.  
 
Weight is due to gravity, and it acts vertically, pulling the aeroplane down toward the centre of the Earth. We all experience this force. When we stand on the ground, the equal and opposite force required by Newton’s third law is the reaction force from the solid ground upwards on our feet.

If we jump, the reaction force from the air cannot outbalance our weight, and so we return to the ground. In order to counter this process, aeroplanes rely on lift to keep them flying in the air.
 
Lift acts in the opposite direction to gravity. It is generated by a clever design principle. If you look closely at the wing of an aeroplane, you will see that the bottom part is flat and the top is curved (roughly speaking).

When an aeroplane accelerates due to thrust from the engines, air will split around the wing, with part of it flowing over the top and part of it flowing underneath. The stream of air flowing over the top will accelerate. As it does so, its pressure decreases compared to the air flowing beneath the wing. This is known as Bernoulli’s principle.
 
The difference in pressure between the air below the wing and the air above the wing causes an upwards force on the wing — lift. When the force of lift is greater than the weight of the aeroplane, it is able to move upwards in the air.
 
These fundamental principles have governed aeroplane flight ever since the Wright brothers first took off in 1903. Yet with the astronomic rise in the frequency of passenger planes, travelling thousands of miles across the globe, aeroplane engineers have had to work hard at making aeroplanes safe and comfortable for the hundreds of people aboard.
 
Safety regulations and innovative engineering mean that aeroplane travel has long been considered reliable and trustworthy. However, recent disasters involving Boeing aircraft have fed into widespread fears about the safety of aeroplanes.
 
If you’ve travelled on a commercial flight, chances are you’ve flown on a Boeing aeroplane. In 1957, Boeing produced the first successful commercial jetliner for mid- to long-range flights, the 707.

In the decades that followed, Boeing went from strength to strength, with the 727 developed to allow airlines to reach airports with shorter runways and the 737 developed for shorter, European inter-city routes.

Boeing aircraft were so popular amongst pilots that the phrase, “If it ain’t Boeing, I’m not going” was coined — a phrase that is now plastered on various Boeing branded items like buttons and T-shirts which can be purchased from their online store.
 
And yet, Boeing has recently experienced widespread criticism due to recent incidents involving its aircraft. In January 2024, an Alaska Airlines Boeing 737 MAX 9 experienced an uncontrolled decompression of the aircraft due to a door plug blowing out. Nobody on the flight was injured, but people travelling on two Boeing 737 MAX flights in late 2018 and early 2019 were not as lucky.

Lion Air Flight 610 and Ethiopian Airlines Flight 302 both crashed, causing the tragic death of all people on board, with a total of 346 fatalities. Investigation of the incidents found up to nine contributing factors to the disasters.

Whistleblower Sam Salehpour, a Boeing engineer, stepped forward in April 2024 to state that Boeing took shortcuts when manufacturing its 777 and 787 Dreamliner jets, and the results could be equally catastrophic. So what went wrong for Boeing?
 
In 1997, Boeing merged with another aeroplane manufacturer, McDonnell Douglas. This merger marked the start of a shift in priorities for the company.

Previously, Boeing had been led by engineers, with the innovation of quality, safe aircraft as their primary focus. But with the deregulation of airlines by US presidents Jimmy Carter and Ronald Reagan, the economic focus of the industry had changed. With more competition, the priority became cutting costs in order to undercut their rivals.
 
So when the merger with McDonnell Douglas happened, the creation of shareholder value began to take precedence over ground-breaking engineering. The new finance-oriented culture was devoted to cutting costs and improving business performance measures such as return on assets and time-to-market, rather than engineering design, production process designs and supplier management.
 
Boeing also began outsourcing in order to decrease turnaround time and cut costs. Traditionally, suppliers would produce parts designed specifically by Boeing engineers for assembly. But in the development of the 787 Dreamliner, Boeing outsourced 70 per cent of the design, engineering and manufacturing of entire modules to over 50 strategic partners.

These contractors often outsource to other subcontractors, creating a confusing, opaque supply chain. There are ongoing safety concerns about certain components used in the 787, such as the epoxy tape used to connect the wings and the middle-fuselage.

The 787 also featured in whistleblower Sam Salehpour’s complaint about the company; he alleged that crews assembling the plane failed to properly fill tiny gaps when joining separately manufactured parts of the fuselage.  
 
Another concern surrounding air travel is its impact on global warming and air quality through greenhouse gas emissions. Passenger air travel is the sector responsible for the highest and fastest growth of individual emissions, yet the high costs of improving aeroplane efficiency or decarbonising the industry entirely mean that this is unlikely to change.

The aviation industry remains heavily backed by government subsidies and therefore has little incentive to make the switch to carbon-neutral fuels.
 
Although crashes and fatalities from aviation disasters remain rare (according to MIT statistician Arnold Barnett, the worldwide statistic for death risk per boarding was one in 13.4 million for 2018-2022), crashes due to shoddy engineering raise difficult questions. Boeing’s trajectory indicates that putting profit ahead of other more basic principles is a recipe for disaster.