Ask Captain Lim ~ All about Aviation

Hi Captain Lim,

I appreciate the site and the info - I don*t mind turbulence that much but when we*re in it I always dread the unexpected 100 ft drop. So it was nice to read that those rarely happen away from bad storms.

I notice when I sit in the rear center seat of smaller planes and look out of the cockpit windows, the plane doesn*t exactly fly straight - it sort of twists back and forth. Do larger commercial planes do the same thing?

Do you get vertigo when flying through clouds or snow?

And the ultimate question that I*m amazed nobody has asked - why do the window shades need to be up during takeoffs and landings?

Thanks.

Steve

Hi Steve,

Any motion on a smaller plane is generally more obvious than on larger commercial planes.

A well-trained pilot should not suffer from vertigo because he knows when to trust the flight instruments and when not to rely on his senses as he loses visual contact, especially flying through clouds or snow.

Vertigo arises when our equilibrium is off balance. Our equilibrium is controlled by the semicircular canals in the inner ear. Remember, as a kid, you used to spin around until you were so dizzy that you fell down? Well, you have disrupted your balance center.

From a pilot*s point of view, this is also known as spatial disorientation. It describes the condition when pilot*s perception of direction does not agree with reality.

If the pilot is not trained to recognize this condition, he will eventually lose control of the aircraft if he was flying the plane manually. The aircraft will usually end up in a steep, diving turn known as a graveyard spiral. This was probably what happened to pilot JF Kennedy Junior in his single engine crash near Massachusetts Island in 1999 and the pilot of the Boeing 737 crash in the Red Sea resort of Sharm el-Sheikh in 2004.

No, I don*t get vertigo when I have to fly inside clouds or snow. Furthermore, vertigo or spatial disorientation should no longer be an issue as most commercial planes today are flown on autopilots and machines are unlikely to be fooled by any false senses!

The reason why the window shades need to be up during take offs and landings is one based on safety considerations. In the event of an emergency, the Flight Attendants are able to see outside easily in order to make a quick assessment as to whether it would be safe for passengers to evacuate either to the left or right of the plane in case of a fire.