Revealed: The 4 terrifying airplane issues that happen MUCH more often than you think - including engine failures

From 'Sully' to 'Final Descent', airplane disaster movies often make emergency scenarios seem like once-in-a-generation events. 

But, according to a scientist, they're a lot more common than you might think. 

Dr Guido Carim Junior, a lecturer in aviation at Griffith University in Australia, says four 'in-flight technical problems' are just a 'part of flying'. 

Pilots are routinely trained to prepare for these four blunders, of which engine failure is the 'most feared'. 

The vast majority of these instances don't result in tragedy, but they're typically accompanied by Hollywood-style emergency landings and dramatic drops in altitude. 

And they always cause significant discomfort for the paying passengers on board. 

'Most in-flight failures trigger a chain of defences aimed at keeping the flight safe,' Dr Junior says in a piece for The Conversation. 

'Here are four scary-sounding failures you might hear about (or even experience) and how they are actually dealt with in the air.' 

1. Engine failures

Most commercial airlines have at least two engines – one on either side of the plane – that provide the thrust to move the aircraft forward. 

If these both fail, the plane enters a glide and needs to descend in order to maintain forward airspeed and keep it from falling from the sky. 

'After being alerted by the warning system, pilots identify the affected engine and follow the checklist,' said Dr Junior. 

'The checklist typically requires them to shut down the problematic engine, descent to an appropriate altitude and divert if in cruise, or return to the departure airport if after takeoff.' 

In June, the Air India Flight 171 demonstrated what can happen when both engines stop functioning shortly after take-off. 

Mysteriously, both switches that controlled fuel going into the engines were cut off, causing the plane to quickly lose altitude and collide with buildings.  

Twin-engine airliners are actually able to fly safely on one engine, but one-engine failures are treated seriously and thoroughly rehearsed in flight simulators. 

Although not unheard, dual failures are 'exceptionally rare', and have led to fatal crashes. 

A decade ago, TransAsia Airways Flight 235 suffered single engine failure shortly after liftoff from Taipei but tragically crashed after pilots shut down the wrong engine. 

More fortuitous was the 'Miracle on the Hudson' in 2009 – a rare bird strike event that led to both engines stopping. 

The plane safely landed on the Hudson River in New York with no casualties – a dramatic event retold for the film 'Sully' starring Tom Hanks. 

2. Landing gear and brak trouble

Airliners have retractable wheels that remain inside a compartment for most of the flight but come out of the airplane belly before landing. 

Assembled in the wheels are the brakes, which aim to reduce the aircraft speed just after touchdown, much like in a car. 

However, sometimes the landing gear doesn’t extend or retract properly, or the braking system suffers the loss of a crucial hydraulic system. 

If landing gear doesn't deploy, the pilot may issue a 'brace for impact' instruction before landing the plane on its belly, Dr Junior said. 

In absence of working brakes, the pilot may use reverse thrust to slow the aircraft down before landing on a particularly long runway. 

Last December, a Qantas flight QF1929 returned to Brisbane after experiencing a problem with its landing gear. Passengers were told to 'stay down, heads down' while the aircraft landed safely. 

3. Loss of pressure

Commercial planes generally fly above the clouds at altitudes around 36,000 feet – an area of very low air pressure. 

Low air pressure means the surrounding air is less dense and therefore contains less oxygen – which is why we get altitude sickness when we're up a mountain.

Therefore, aircraft cabins need to be maintained at a higher pressure (typical of what we're used to on the ground) and ensure people on board can breathe properly and don't pass out.

Unfortunately, 'pressurisation hiccups' can occur, leading to a dramatic controlled descent, ears popping and oxygen masks dropping, Dr Junior said. 

Last year, Alaska Airlines Flight 1282 suffered sudden depressurization of the aircraft cabin when a door dramatically flew off. 

Luckily, at the time the plane was only six minutes into its journey and was still rising while at an altitude of around 16,000 feet. 

If it had occurred at full altitude, passengers would have lost consciousness in seconds.  

4. Faulty flight controls

There are multiple parts of the plane that control the direction it flies in, including the rudder at the back and the 'ailerons' on at the end of the wings. 

As Dr Junior explains, these are controlled electrically or with hydraulic systems, which simply use fluids to create motion and force. 

Planes are built so that if one control fails the plane will still be able to stay in the air, although the pilot will want to make a quick and safe return to the ground. 

When an issue is detected by the plane warning system, there might be 'a return to the departure airport or a faster-than-normal landing', Dr Junior said. 

Ultimately, these four issues are common and a 'part of flying', but instances of them leading to fatal incidents are much rarer. 

The expert said: 'Pilots train extensively for them. Checklists contain detailed instructions on how to deal with each issue. 

'Aircraft are built with layers of redundancy, and warning systems alert pilots to problems. 

'A dramatic descent or an urgent landing doesn’t mean disaster – it usually means the safety system is doing exactly what it’s supposed to do. 

'The vast majority of flights that experience technical issues end with a safe arrival.' 

Even though turbulence is a common and terrifying experience on a plane, this is not considered a failure like the above four issues, but more an inevitable part of the journey.