CHI97FA293

The pilot departed in the experimental amateur built Skybolt from Rockford for a local flight. Witnesses reported seeing the aircraft fly straight up into the sky, roll over onto its back, and start spiraling towards the ground until impacting the ground. The propeller was twisted and had leading edge nicks.

History of flight

On September 12, 1997, at 1858 central daylight time, an experimental Skybolt, N79DK, was destroyed when it impacted terrain near Adeline, Illinois. The local flight was operating under the provisions of 14 CFR Part 91, and was not operating on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The private pilot and one passenger sustained fatal injuries. The flight had departed the Greater Rockford Airport (RFD), Rockford, Illinois, at 1827 central daylight time.

At 1826.26 cdt, N79DK made a radio transmission to Rockford Clearance Delivery requesting clearance to "depart to three thousand feet to the west practice area." The clearance was issued at 1826.38 for the Skybolt to "maintain v f r (visual flight rules) at or below two thousand five hundred." At this time, N79DK was also issued a departure frequency and transponder code. After receiving instructions to taxi to runway 19 (8199 feet x 150 feet, Asphalt), N79DK was cleared for takeoff at 1833.03. At 1835.15, Rockford Departure instructed N79DK to "proceed on course at requested altitude," to which there was a response 6 seconds later of "nine delta kilo thank you." This was the last transmission recorded from the accident airplane. At 1858, the departure controller noticed that N79DK was no longer being identified by radar. He issued a "radar contact lost" transmission to N79DK, to which there was no response.

At 1859.48 the controller was informed that a phone call was received reporting a plane crash. The controller requested a nearby aircraft to try transmitting to the accident aircraft with no success. The controller then began the notification procedures for an aircraft accident.

According to the Ogle County Sheriff's Office report, witnesses, "saw the airplane fly straight up into the sky, turn over and start spiraling towards the ground." Another witness stated, "[She] did not see the plane go up but said she saw it spiraling to the ground and heard the impact."

Personnel information

The pilot, born January 13, 1951, was the holder of a private pilot certificate with airplane single engine land privileges. He was a licensed glider aero tow pilot as well as a licensed airframe and powerplant mechanic. Federal Aviation Administration (FAA) records indicate that the pilot's last aviation medical examination was performed on March 6, 1996. The pilot possessed a current third class medical with the limitation "must wear corrective lenses."

The pilot reported 1,026 total hours on his application for his last medical certificate.

Aircraft information

N79DK, serial number 055, was a built-by-plans, all wood, dual strutted bi-plane with fixed landing gear in a tail-wheel configuration. The aircraft can accommodate a pilot and a single passenger in a front and back seating configuration. The FAA DuPage Flight Standards District Office (FSDO) certified the aircraft as an experimental amateur built aircraft.

The engine was a Textron Lycoming IO-540, serial number L-2239-48.

Meteorological information

A weather observation facility, located at RFD, located 15 statute miles on a 135 magnetic bearing from the accident site, reported the weather three minutes prior to the accident as:

Observation Time: 1855 cdt Wind: 150 degrees at 3 knots Visibility: 10 statute miles Sky Condition: Sky Clear Temperature: 21 degrees centigrade Dew Point Temperature: 10 degrees centigrade Pressure: 30.07 inches of mercury

Wreckage and impact information

The aircraft came to rest in a bean field in the 10,100 block of North Adeline Road, near the intersection of Adeline Road and Lightsville Road.

The aircraft was destroyed during the impact with terrain. The wreckage was found resting on its bottom side in a wings level attitude.

All of the top spark plugs were in place and undamaged with the leads attached. The number 2 cylinder spark plug was separated, and the numbers 4 and 6 spark plugs were in place with the leads attached. The condition of the remaining 3 spark plugs was not determined due to impact damage.

A post accident examination determined that both propeller blades incurred bending and twisting, one more than the other. Both blades had polishing on the leading edges of the surface and chordwise abrasions, and one blade had several large nicks on the leading edge. The propeller was separated from the crankshaft exhibiting fracture surfaces typical of shear overload forces. (See attached propeller and propeller flange photographs.

Inspection of the flight control system did not disclose any evidence of any preexisting anomaly with the flight controls.

Medical and pathological information

An autopsy was performed on the pilot by the Ogle County Coroner's office, on September 13, 1997, in Oregon, Illinois.

A Forensic Toxicology Fatal Accident Report was prepared by the FAA Civil Aeromedical Institute, Oklahoma City, Oklahoma.

The toxicology report indicated the following results:

*No Cyanide detected in Blood *No Ethanol detected in Vitreous fluid *182.500 (ug/ml, ug/g) Salicylate detected in Urine

According to the Laboratory manager, salicylate is a non-impairing, over-the-counter analgesic, a metabolite of aspirin.

Additional information

Parties to the investigation were the FAA, DuPage FSDO, and Textron Lycoming, St. Charles, Illinois.

All wreckage was released and returned to L.J. Shaw and Company, Lombard, Illinois.