Status: experimental speed canard modification of former Berkut prototype
Type: canard pusher aircraft
Powerplant: 1 x Lycoming IO-540
Significant date: 2003
The Berkut has had its share of race wins beginning with the prototype in July of 1992. Berkut placed first in the Jackpot Nevada EZ Bash, coming in at 240.96 mph. In 1993 at Sun n Fun, the Berkut finished first in the Class 2A race, averaging 247.19 mph from a standing start. In addition to races, Berkut entered the exciting world of air shows. The Berkut made its air show debut in Santa Ynez in the Spring of 1993. At the controls was Commander Rick Fessenden, ex-military F-18 pilot and company test pilot for Dave Ronneberg's Experimental Aviation, Inc., of Santa Monica, California. Some of the most spectacular air show performances ever seen were performed by Rick who put the aircraft through its paces.
Unfortunately, the Berkut in air shows ended on August 12, 1995, during an air show demonstration routine at Santa Paula, California, when during a sustained 9G turn, the N91DR Berkut prototype, with Fessenden at the controls, apparently experienced G-loc and did not recover. The Berkut collided with the ground following a loss of control. Visual meteorological conditions prevailed. The aircraft was destroyed in the ground collision sequence, while the certificated airline transport pilot sustained fatal injuries. Many ground witnesses, including other air show pilots and Federal Aviation Administration (FAA) inspectors, witnessed the accident sequence. All of the witnesses heard engine power sounds throughout the sequence-to-ground impact. In addition to the witnesses, a spectator videotaped the entire performance of the aircraft to include the accident sequence. Review of the videotape disclosed that the sequence as viewed matched the witness observations of the accident.
An FAA inspector said he observed the aircraft do what the narrator described as a complete 360-degree 6g turn, which was immediately followed by the 8g knife edge minimum radius turn to the left. About 270 degrees into the turn, many witnesses saw the aircraft "burble" or rock the wings slightly. The videotape showed the aircraft increase the angle of attack just before the "burble" was observed. Following the burble, the left wing dropped and the aircraft rolled left 270 degrees to a near wings level flight attitude. The aircraft then descended in a nose-up pitch attitude behind a tree line and impacted the ground. The aircraft designer/builder stated that the 8g minimum radius turn looked normal until the 270-degree point. The aircraft then looked as if the turn tightened and the aircraft rolled left. His impression was that the aircraft did a full 360-degree roll until the time it disappeared behind the trees.
On-site examination of the aircraft by FAA inspectors established that all of the aircraft components were accounted for in the wreckage distribution path. The fuselage was extensively fragmented and distributed over a 210-foot-long path. After recovery of the aircraft from the site it was examined again in detail by FAA airworthiness inspectors. The inspectors reported that no discrepancies were found. Air show pilots who performed immediately before the accident pilot's routine were interviewed. The pilots reported that the airmass was smooth with no unusual turbulence or other meteorological phenomena noted. Other air show pilots familiar with the accident pilot reported that before the flight the pilot appeared rested and his normal self.
A witness to the crash said that the demonstration routine (including the 8g minimum radius turn) performed at the time of the accident was the same one flown by the accident pilot since 1992. In an interview, Dave Ronneberg stated that during flight test, no main wing stall had been induced due to g-loads imposed on the aircraft. The ultimate design load factors were g-loadings of 14 positive and 7 negative. Eventually, the National Transportation Safety Board determined the cause of the accident as "the pilot's inadvertent entry into an accelerated stall in a maximum performance high-g turn at an altitude insufficient to recover aircraft control prior to colliding with the ground". With Rick Fessenden's death, the aviation community lost a great man.
Dave Ronneberg decided to rebuild the wrecked Berkut prototype, which finished its racing career where it all began, in Jackpot, Nevada, placing first once again in the Unlimited Class with a speed of 245.45 mph. It also won Jackpot Races in 1996, '97 and '98. Finally, Ronneberg decided in 2003 to incorporate the latest improvements on the prototype and to use it as a testbed. Now powered by a pumped up Lycoming IO-540 engine, the rebuilt #001 thus became the fastest Berkut ever built to date. Now called the Super Berkut 540, it used a beautiful Aero-Composites 3-blade constant speed prop, and Blue Mountain EFIS/One. "The Super Berkut 540 easily zips through the sky at more than 270 miles per hour and can still drop like a rock when desired" said an enthusiastic advertisement.
David Ronneberg has proceeded with solo development of the Berkut for the UAV (Unmanned Aerial Vehicle) market. Berkut Engineering & Design has helped create a classified special-mission UAV concept and proposal under the guidance of consultant Stayne Hoff, resulting in a developmental contract from the US Air Force for about a million dollars late in 2003. This was most certainly an unmanned (or perhaps optionally-piloted) derivative of the Super 540 demonstrator. The presence of the USAF's UAV Battle Lab logo on the winglets of the Berkut prototype and the fact that the company appears in the DoD's contractors for both fiscal years 2004 and 2005 clearly indicates the military's interest in the unmanned Berkut.
Population: 1 (c/n 001, former Berkut prototype) [N91DR]