"On October 25, 1999, a chartered Learjet 35 was scheduled to fly from Orlando, Florida to Dallas, Texas. Early in the flight, the aircraft, which was cruising at altitude on autopilot, quickly lost cabin pressure. All on board were incapacitated due to hypoxia—a lack of oxygen. The aircraft failed to make the westward turn toward Dallas over north Florida. It continued flying over the Southern and Midwestern United States for almost four hours and 1,500 miles (2,400 km). The plane ran out of fuel and crashed into a field near Aberdeen, South Dakota after an uncontrolled descent. The four passengers on board were golf star Payne Stewart, his agents, Van Ardan and Robert Fraley, and Bruce Borland, a highly regarded golf architect with the Jack Nicklaus golf course design company."
Nobody knows why this aircraft depressurised. The Learjet is well known to be a most reliable aeroplane, it is a very popular choice as a Business Jet.
Other aircraft have depressurised because of the freight doors, for ecample, blowing off in flight and so, while exceedingly rare, it is not an unknown occurrence.
Well, let’s think about what might happen at around thirty five thousand feet (about ten and a half thousand metres).
The ambient pressure at that altitude is lurking around three pounds per square inch. Not much. This means that the air is below a pressure that might be regarded as ‘breathable’. The oxygen content of the atmosphere will be limited and, certainly, inadequate to sustain life.
The temperature, according to the International Standard Atmosphere approximates to minus fifty-six degrees Celsius. This is extremely cold.
But it is the lack of pressure that will get you.
On a passenger aircraft a sudden drop in cabin pressure will initiate a response from the emergency breathable oxygen system. Facemasks will suddenly drop from above the seats to dance enticingly in front of each occupant of the aircraft.
The instructions given to passengers include the need for adults to see to their own masks first and then, when theirs is fitted, to apply the mask to the children.
Naturally, a mother will want to see to the squirming, and frightened, child first. She will have difficulty in doing this and so both of them will now die.
So quickly? Indeed. It is that low pressure that sucks the air out of your lungs; it is that low pressure that stops your lungs from extracting what little oxygen there is.
Combine that with the shock of being plunged into a temperature of minus fifty-six degrees Celsius.
Most of the passengers will die in the first few minutes.
The rest will gradually go to sleep and slip away into death through hypothermia soon afterwards.
What about the crew?
The flight crew have their own oxygen supply. It is still very cold but they do have oxygen.
The problem they face is that they have to reach it. The mask does not appear in front of their face as with the passenger system, they have to physically turn and grasp the facemask, remove it and put it on. This takes time.
What if they are fumbling? Shock does strange things.
They will get hypoxia—oxygen starvation.
Watch soccer referees and you will see that they run further than any of the players, generally speaking. Notice that they make most of their (perceived) mistakes at the end of the match. Why? Hypoxia. Their brains are being starved of oxygen through all that running. Superbly fit though they certainly are, they will still get oxygen depletion.
Lack of oxygen makes decision making problematical.
Maybe the pilot has oxygen starvation or, perhaps, it is the first officer given that the pilot may be already deceased. Now, thinking that he is flying in a straight line he is, in reality, pursuing an erratic course around the sky involving not just change of direction but change of height, too.
Eventually he, too, succumbs to the cold and ultimate oxygen deprivation. The autopilot holds a steady course on the last heading given until the aeroplane runs out of fuel.
The engines stop but the batteries will give thirty minutes of emergency electrical power to essential services and so the autopilot, even with the engines stopped, holds the aircraft on course.
It glides gently down until it alights on a reasonably calm sea.
Maybe the engines are torn off and, perhaps, a wing. But these are major components that are lost, there is no huge break up into small parts to float around the ocean for rescuers to find.
The engines sink immediately and the wing will go down once the sea has flooded the fuel tanks through the tank vents. And then the fuselage drops through the depths because it fills with water through the missing freight door.
Remember the missing freight door?
Everybody on board died hours ago. Peacefully, in their sleep.
In reality, flight MH370 was abducted by aliens...