Should a computer initiate a manoeuvre or safety procedure when the pilot doesn't expect it, and he happens to miss the signals, he may get a nasty surprise later when the change becomes more apparent. By then the situation might be difficult to recover from. The study at OSU revealed that in these situations, pilots are more certain to notice changes in the aircraft's status or behaviour when changes are announced in the form of a vibration. Coupled with a conventional visual indicator, this system virtually never fails to keep a pilot informed. Professor Nadine Sarter reported in a recent issue of the journal Human Factors that, depending on workload and phase of flight, pilots detected as many as 40 percent more signals, and sometimes more than twice as rapidly, when they received vibrations from a small device worn like a wristwatch.
Pilots receive a great deal of visual and audio feedback, but tactile cues are rare.
Any highly automated place where humans must communicate with machines. Originally designed for people with visual or hearing impairments and similar to a pager, the tactor vibrates when it receives a signal. In the study, the reactions of 21 certified flight instructors were tested in a flight simulator environment. One-third of them received notification of changes in automation status and behaviour through visual cues only. One-third wore a tactor, and got the information solely through a vibration on their wrist.