In many years of commercial aviation, I've heard tons of false myths.. Let's have a look at the most common ones!
- Right after landing, you can hear the engines revving up: they are spinning backwards to reverse their thrust:
I have heard this comment many times... this statement is absolutely wrong!
Apart from being something against the laws of physics, a jet engine, as well as a propeller one, is designed to only spin in one direction and cannot spin the other way around. (more info here).
What really happens is that right after touchdown pilots activate devices called "reversers", which deviate towards the front the jet stream coming out of the engine, thus contributing, by increasing engine power, in slowing down the aircraft.
In propeller aircrafts, "reverse thrust" is obtained by changing the angle of the propeller blades in order to push the air forward instead of backwards. - During long flights, the cabin is cold because pilots reduce cabin heating in order to save fuel:
Not! The way the conditioning system is designed is such that more or less heating in the cabin does not impact fuel consumption! It wouldn't make any sense...
Usually, a good reference temperature in the cabin is around 24 C (75 F), but there are a few factors that might influence the actual value:
- conditioning system efficiency: depending on aircraft type, age and general system conditions, temperature regulation might not be fully accurate;
- physics! The passenger cabin is, for most of the time during a flight, "tilted upwards", so that its front is slightly higher than its back (of an angle called "angle of attack"). Since hot air tends to go up, it is common to find the front of the cabin warmer than the section towards the tail. In order to reduce this issue, temperature control is usually divided into "zones", so that temperature in different sections of the cabin can be independently regulated. - It is possible to make free cellphone calls from on board an aircraft, because due to the high speed, fast cell switching will trick the mobile network. That's why they force me to turn "airplane mode" on:
If you were allowed to keep your mobile on, you would discover that there is no reception from shortly after takeoff, all the way to shortly before landing.
Mobile networks only work if there are antennas available within a few kilometers horizontally, and there is virtually no signal propagation vertically. How can you think of getting any signal at thirty thousand feet up in the sky?
Lately, more and more airlines offer (for a charge!) the possibility of making phone calls using a "local network" inside the plane, which, in turn, is linked to the ground network via a satellite connection. - A flight from A to B takes longer than the one from B to A because of Earth rotation which is added or subtracted to/from the aircraft speed:
Absolutely not! The airplane moves inside the atmosphere, which in turn moves together with Earth in its rotation. It's a "closed system", for what we are concerned Earth could as well stand still or spin vertically, we wouldn't notice anything on board our aircraft.
Flight time is strongly influenced by winds. Take a look at airplanes and the winds(sorry, not yet published) to know more about it.
If we want to be picky, because of Earth rotation, a flight from East to West is a few millionths of second longer than the same flight from West to East... But that's another story! - It is preferable for airplanes to land in the direction of the wind:
Not... Take a look at airplanes and the wind(sorry, not yet published) - (This is nice, but trust me... I've heard it!) Earth is flat, because if it weren't so, an aircraft flying straight would go out of the atmosphere and into space:
I refuse to comment on this one... - Airplanes are used to secretly spray harmful substances into the atmosphere, the so called "chem trails":
On this topic too, I'd rather not go in deep, because I am sure I would trigger debates that would carry the post totally out of topic.
If you can live with just a few words about it, I only tell you this: NO, commercial airplanes do not spray anything... the contrails you see in the sky are just the outcome of simple physics phenomena, perfectly explainable and provable.
