After reading Kai Koerner’s response to my article "By The Numbers: Attempts to Fire an AAD Under Canopy", I feel it necessary to clarify a couple of misconceptions that Kai has about the testing. The length of Kai’s letter precludes a point-by-point treatment, but I will address the main points.

First, Kai’s characterization of my canopy descents as "out of control" is off the mark. As stated in my article, the input to the canopy was with harness only. This results in a rotation speed of three to five seconds per 360 degree turn. This type of input is well known among pro swooping competitors as the most efficient way to dive the canopy to build vertical speed which can then be translated to horizontal speed for the swoop. In fact, this type of dive has a faster descent than a rapidly spinning malfunction, as noted when Kai describes the several fatalities where jumpers went in under spinning mals and the CYPRES failed to fire.

Further, to infer that I discontinued this type of descent because it is unsuitable as a landing approach is erroneous. My tests were conducted on a busy summer day from an Otter that was full each time. Even after pulling high, my landing timing coincided with the mid-point group of freefallers from the plane (those jumping moderately wingloaded canopies). Even if I were to ignore the "no turns over 180 degrees" rule for the main landing area, it would have been unsafe to perform 360’s and 720’s with so much canopy traffic. That is the reason I conducted my tests at higher altitudes, which I tried to make clear in the article.

Kai is quick to point out that to date, no one has fired a CYPRES on a landing approach, even with the advent of highly loaded cross-braced canopies. The only problem with that claim is that many of us who are doing high performance landings have separate rigs without AAD’s. The reasons for this are twofold; in general, swoop competitions involve doing hop ‘n pops, which carry a very low risk of unconciousness during the freefall, and they generally involve a body of water which doesn’t mix well with the original CYPRES. As I stated in my article, the advent of the CYPRES 2, which is being specifically marketed as pond-swooper-friendly, once again raises the question of misfires during landing.

Kai’s description of the testing conducted in October of 2000 by Luigi Cani raises an important question. Kai states "...Even when reaching 78 mph for a moment, the Expert CYPRES would not activate. The reason is that CYPRES does much more than trigger based on measured descent rate and altitude...". The manual, however, states that a CYPRES will fire as low as 130 feet if a descent rate of 78 mph is reached. Airtec owes it to the skydiving community to be more specific about the parameters under which the CYPRES will fire so that people can make a fully informed decision about its use.

Lastly, Kai states that "Troy admitted that it would not have been possible to reproduce the results without adjusting the activation altitude." I didn’t state that anywhere in the article. On the contrary, I think it’s likely that a CYPRES can be fired on a high performance approach without adjusting the activation altitude. Since Airtec seems reluctant to accept the results of my original test, I will perform a new series of tests using actual landings. Stay tuned for the results...

Troy Ketsdever

Parabola Canopy Swoop Team