I believe this has to do with sensory inconsistencies.
When you’re on the ground, your brain interprets different signals when trying to keep balance : the solid ground feeling from your feet, the sight of the terrain around you, and your inner ear. I could see the following contradictions happen between these signals (or other combinations) :
If you’re in an aircraft, you see no ground continuity, and you don’t feel stuck to the ground, hence no contradiction and no brain confusion. Your balancing is just disconnected (you’re generally sitting as well so it’s not needed anyway) and your inner ear is free to feel what it wants.
It’s the same phenomenon as being car sick : some people just have to close their eyes in order to avoid the contradiction between what your eyes see (an immobile car interior, a book), and what your inner ear feels (acceleration, rotation).
You can potentially get used to it too. When I first moved in I was quite scared of my 6th floor balcony, now I don’t feel anything and can look down without issues.
maxbc wrote:
If you’re in an aircraft, you see no ground continuity, and you don’t feel stuck to the ground, hence no contradiction and no brain confusion.
but
maxbc wrote:
sensory inconsistencies
will happen when flying aerobatics, as the sensory hair cells react in contradiction or late on the acquired visuals. Also here one can get accustomed to. Many pilots are having upset stomach when starting with aeros, but this will usually disappear with training.
Was a good thing for me 
hazek wrote:
Are you afraid of heights or are you afraid of falling
You might be on to something. I don’t feel any uneasiness in a harness with a rope tied to a solid and trustworthy structure. But on the other hand I can imagine myself without wearing a seatbelt in an airplane with the doors removed. I haven’t tried it but in my imagination it feels safe.
Also, I was always under the impression that reason can not suppress such basic instincts instantaneously and they must be trained away in a longer period of time.
Someone told me many years ago that some research was done on this and the conclusion is that “you” don’t trust yourself to not step over the edge.
That is probably applicable only to situations where you could step over the edge e.g. standing on a ladder. I really hate ladders and such but have no problem standing in tall buildings e.g. the Eiffel Tower where (nowadays) you absolutely cannot step off anywhere.
Therese and I had a bizarre experience of vertigo once while flying. Neither of us has any fear of heights while flying GA aircraft, though both of us get very tingly feet if we get close to a cliff edge on foot or even in a car in the mountains.
Anyway, one day we were flying a club plane slowly around the Swiss Alps. We flew very low (100 ft agl) over a high plateau and then suddenly and unexpectedly proceeded right over the edge of a sheer drop, many hundreds of feet high. We both experienced the worst vertigo of our lives. Very strange.
I had the same experience. Taking off from La Seu LESU (Andorra) I accelerated very low over the rwy knowing there is a huge cliff just beyond. Also felt vertigo but fortunately very briefly. I suppose your and my bodies interpretated this as driving of a cliff.
That going off a cliff experience is a well known thing exploited to great effect in cinema and theme parks.
BTW that is not vertigo. Vertigo always gets a bad rap when it comes to heights.
Vertigo is a sensation of motion or spinning or dizziness.
Glad to know I am not alone !
Jujupilote wrote:
Glad to know I am not alone !
I read somewhere on the interwebs a while back that pilots are over-represented in the population of people that have “fear of edges”. We also seem to have a higher rate of “call of the void” experiences.
