Rush to Judgment

Art by Lou BeachWITH EACH WELL-PUBLICIZED AIRPLANE ACCIDENT, another of the mysteries of the pilot's world is laid bare to the public. ValuJet unveiled solid-oxygen generators (the dirty little secret of the drop-down mask!). Swissair 111 uncovered fuel dumping and maximum landing weights. And now JFK Jr. has exposed the Instrument Rating.

The rating is an appendix to a pilot's license that authorizes him or her to fly without visual reference to the horizon or the ground. John F. Kennedy Jr. had been studying for one before his small plane, with his wife and her sister aboard, plunged into the waters off Martha's Vineyard. Everything about the accident pointed to a sudden loss of control: the unmotivated right turn indicated by the final radar echo, the lack of a distress call, the precipitous descent that could only be achieved, in a Piper Saratoga, by banking very steeply or by rolling the airplane over onto its back. One explanation is that Kennedy lost his visual bearings; so media pundits have decided the instrument rating that he did not have would have saved him.

But the accident scenario is not so simple and obvious. As a private pilot and instrument student, Kennedy already possessed the basic instrument-flying skills that he needed to find his way to Martha's Vineyard airport in hazy conditions, or, failing that, to turn back toward the brightly lighted Connecticut coast. Nor does his inexperience necessarily explain anything; Navy pilots with the same number of hours as Kennedy are landing jets on carriers. Despite some nonsensical pronouncements to the contrary, Kennedy's was not a "high performance" airplane (except perhaps in the view of Piper salesmen) and did not require a "butterfly touch" to fly. And it was equipped to fly itself.

THE INSTRUMENT RATING IS NOT THE PANACEA the pundits would have us believe. The experience requirements are very minimal: You must have a private pilot's license, with 40 hours of instrument practice, of which 20 may be logged in front of a home computer. There's a flight test, and a written exam that many pilots dread as one of the more daunting challenges in aviation.

The fundamental reason for the instrument rating is that you can't keep an airplane upright just by "seat of the pants" feel. The balancing apparatus in the inner ear is unable to distinguish between position and motion. That ambiguity accounts for the illusions you get in Disneyland's Star Tours ride, which is, in fact, based on a type of hydraulic motion platform originally designed for pilot training. A steadily turning airplane feels just like one flying straight; the coffee remains level in your cup, the stewardess stands upright in the aisle, even when the airplane is banked. The brain expects the eyes to resolve the inner ear's uncertainties, and so once a pilot is deprived of visual references he is helpless without some kind of artificial means of knowing which way is up.

That information comes from instruments containing gyroscopes, which hold their orientation in space as the airplane revolves around them. Airplanes use two basic kinds of gyros: the attitude indicator, or "artificial horizon," which presents a simplified picture of the airplane and the horizon ("attitude" is a pilot's term for the airplane's position -- nose high or low, banked, and so on); and the directional gyro, which tells which way the airplane is headed. There is also a backup attitude gyro called a turn-and-slip indicator. Gyros can be driven electrically or by an air pump on the engine; whichever power source the main attitude indicator uses, the turn-and-slip uses the other, so that a single failure won't deprive the pilot of all of his attitude information.

Flying by reference to gyro instruments isn't hard. Some beginners even find it easier than flying by reference to the outside world. It gets harder when you throw in turns and climbs and descents and navigational fixes and glideslopes and turbulence; but just keeping an airplane right side up or making gentle turns by reference to instruments is very easy.

Kennedy, like every student pilot, had already spent time flying by instruments alone. The FAA flight test that he took to get his private license includes some maneuvering while wearing a tunnellike visor that blocks your view of everything except the instrument panel. The intent of the requirement is that if a non-instrument-rated pilot accidentally flies into a cloud (or, for that matter, into a haze layer at night), he should have the ability to turn around and fly back out.

Much of the rest of instrument flying has nothing to do with staying upright, but rather with air-traffic control. Something must be done to keep blind-flying airplanes from running into one another. The current solution to the problem -- which has been in use, with various technical improvements, for more than half a century -- is to have controllers on the ground keep track of all flights, anticipate conflicts and tell pilots what to do to avoid them. When pilots work on their instrument ratings, they are mainly learning the very considerable complexities of taking off, navigating and landing within the air-traffic-control system, with visual references only at the very beginning and very end of the flight.