Degrees of Tolerance

by Norm Heaton
USPA Executive Director

They're different and they're unique. They're a weird looking parachute. Some go so far as to doubt whether they are even a parachute in the strictest interpretation of the definition. They can be a heck of a lot of fun, a different sensation accompanies each jump as you literally fly around the sky. They are so radically different from the standard parachute they represent a minor revolution in the industry. These are the new gliding canopies now on the market, more specifically the ram-air parachutes.

There's another side to the picture however. People are getting hurt jumping them, seriously hurt, and it has become increasingly concerning. Within the past month two extremely serious injuries have occurred to users of the ram-air parachute, injuries so serious one man is in danger of losing his leg and another is hospitalized with extensive brain damage and near death. Both these accidents, and others less serious in nature, have resulted from landing under a ram-air parachute. Injuries that go beyond the more commonplace broken ankle or even a broken leg. These are injuries so serious permanent damage has resulted.

The most recent injuries have occurred under circumstances difficult to understand; the jumper was flying the canopy in what was believed to be an acceptable manner, witnesses report no radical control procedures were performed prior to jumping the canopy, and each had several jumps on the canopy before the accident occurred. Yet something happened, the canopy experienced a radical change in flight characteristics resulting in serious injury on landing.

Is it logical to suspect there is an inherent danger in the new gliding canopies? Our initial reaction was no, the canopy was so new and so different from conventional canopies it was generally accepted the jumper must have committed a serious handling or control error (which has been the case many times). A more reasonable approach to the problem, and there is a problem, may be found in the "degree of tolerance". Simply explained, the degree of tolerance when using the ram-air parachute is considerably narrowed when compared to the conventional (round) canopies.

A round canopy, even the universally popular Para-Commander, is very forgiving. The degree of tolerance is very large. However, the P-C is not as forgiving as the 7/TU, and we experienced a rash of injuries after the introduction of the slotted, center-line type canopies in 1964. Many people discovered, sometimes painfully, the P-C reacted differently from their old 1.6 lo-po. The degree of tolerance had narrowed.

The same thing has occurred with the introduction of the super gliding canopies, but more drastically. The area of tolerance has shrunk proportionally to the near-amazing capabilities of the ram-air parachute, a vehicle so far removed from the conventional parachute it's like comparing a Ferrari to a farm tractor. The ram-air canopy is considerably less forgiving; radical control procedures result in radical, yet explainable, reactions; control and handling techniques for conventional parachutes no longer apply in most cases; it's a machine that creates lift because it flies and it must fly to remain inflated and controllable. The degree of tolerance has narrowed to the point where extreme caution, delicate handling and mental alertness are critical essentials.

It has long been our position, often disagreed with, that the ram-air parachute is not for everyone. Their unique characteristics are such one is entering a more complicated area of parachuting, requiring a more sophisticated knowledge of aerodynamic techniques.

We are not recommending that you not jump these canopies or purchase one if so inclined. We are attempting to impress upon everyone the tremendous differences that exist between what most of us are used to when it comes to parachutes and the radically new field of ram-air parachutes. Some have mastered this new field as aptly demonstrated by the performances of such men as Tom Schapanski (8th Place Accuracy, '71 Nationals), Grady Steensrud (seven dead centers, '71 Nationals), Dick Morgan and a number of others. They have demonstrated they have made a successful transition from the conventional to the new. They have disciplined and adjusted themselves to the narrowed degree of tolerance.

The point being: ownership of such a piece of equipment is not automatically accompanied by an improvement in parachuting skills. While it does provide the means to improvement it also has the potential, on a larger scale than ever before, to cause injury to its user if mishandled. The a priori assumption of "if it's a better parachute and I have one of them I'll be a better parachutist" simply has no universal application in this instance.

This is very responsibly and accurately pointed up by part of the text of the "disclaimer" for the ParaPlane as found in the "Para-Flight Manual" of ParaFlight, Inc:

"It must be understood that this is a gliding type parachute which has flight characteristics unlike conventional parachutes, and therefore, must be used and controlled by persons who thoroughly understand these performance capabilities and limitations. Certain control maneuvers, improperly executed by the user may cause serious injury and death, especially if these maneuvers are performed at too low an altitude. Further, this is a sensitive device which may be easily damaged, and a malfunction may occur from improper use, accidents, striking, alteration, excessive use, misuse or abuse, for any and all of which the Seller will not be liable."

The appearance of the ram-air parachute has again illustrated the brillance of American technology, it may well revolutionize the entire concept of parachuting on a worldwide basis. But as with most technological change the beneficiary must adapt himself and in this instance this is done through a complete awareness and a thorough understanding of the capabilities of both the man and the machine.

The limits of tolerance are narrow; the penalty for exceeding those limits swift and disastrous.
NEH

Published in Parachutist October 1971.