You Asked for It
December 2003

Question about ergonomics of being a pilot:

I am the Occupational Safety and Health Coordinator at a small airline based in Winnipeg. I read with great interest your article about the ergonomics of driving a car, which was in an issue of Canadian Occupational Safety.

Of particular interest was all the details about what happens to the back - i.e. the stresses on discs and muscles. Your article had a lot of information. The article made me wonder if the same stresses and pains are happening to a pilot sitting in the aircraft chair when flying.

We have small 18 passenger turbo prop aircraft, and the captain and first officer do sit for an hour or more on some flight legs, and sometimes immediately start unloading freight or baggage upon landing. Currently, pilots are advised they should stretch a bit and not jump right into unloading, because they had been sitting in a somewhat confined position for a time.

Do you have an article or could advise (or suggest where I could go for help) what a pilot's back is undergoing when they sit for an hour or so in an aircraft seat.

George

Response:

The only significant difference between the physical conditions of driving a car and flying a plane would the frequency of vibration that the operator is exposed to. Both require the operator to be relatively stationary in a seated position, operating pedals and levers while doing a vigilance / monitoring task. The vibration difference comes into play in that the plane would have much more high frequency vibration versus the vehicle which has more low frequency vibrations associated with road conditions. In terms of the risk of back injury, lower frequency vibrations are more of a risk due to the low resonant frequency of the torso. When the exposure frequency is the same as the torso's resonant frequency, the amplitude of the movement is exaggerated, increasing strain to the spinal discs. In long distance drivers, this is a factor contributing to degenerative disc disease.

Pilots face another risk though, that drivers can avoid. Pilots cannot stop the plane and get out and move around (whereas drivers can pull off the road and go for a walk, if they need to). In the smaller carriers there isn't even enough room for the pilot to stand up and straighten out his/her body. In the larger carriers, the pilot cannot leave the cockpit due to the increased security. So, the issues around being stationary are even more important. Introducing seated or semi-seated movements will help reduce some of the risk during the flight time. When the pilot must assist with baggage handling, I would encourage him/her to first escort the passengers to the terminal or to walk the long way around the plane to get to the hatch. Along the way, the pilot should take a few seconds to (at the least) stretch up to the sky and do a lumbar extension stretch. You can find both of these stretches on my web site.

I hope that helps.

Question about Glare in the workplace

Hi Sharon, I read your article, it is very good. One question I have for you is that with the new open office design that some companies are going to, seem to position the employees around the windows - this causes glare on the screens from the sunlight shining directly onto the screen. I know everyone says to close the blinds, but then the people on the far inside of the office are not getting the benefit of the outside light. My suggestion would be to install a bottom up blind, where the top half of the window would be open and allow the sunlight into the office. Do you know of any companies currently using the bottom up blind and where one could get any information on this?

Renay

Response

I like the idea of a bottom up blind. I have seen these used in homes so that people have privacy from peeking eyes from the street, but still have the natural light shining in. I have not yet seen this concept used in the office environment, but I think it would work.

The other thing that helps is to understand that all the blinds in the office do not need to be closed. Only the blinds that are effective to block the reflected glare on the screen or the direct glare in the workers' eyes need to be adjusted. Basically, windows that are immediately adjacent to the worker or those that can be seen reflecting on a blackened screen should be closed. Others that provide illumination for reading and writing tasks or general levels of natural light should be left open. It has been documented (though I can't recall the reference) that being able to see natural light has a greater positive impact on mood and affect than simply increasing the illumination level overall or adding full spectrum bulbs.

If you come across an industrial blind supplier who is doing bottom up blinds, I'd be most interested in hearing about their product.

st

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