IONA, ID, USA
N11PU
Pitts 11
A videotape of the accident showed the aircraft successfully completing a series of two counter-clockwise aileron rolls, immediately followed by two clockwise snap rolls. During the second run of maneuvers, initiated from an approximate altitude of 100-200 feet AGL, the aircraft recovered from the final snap roll in a 90 degree right-wing down, nose low attitude rather than the wings level attitude of the previous maneuver. One to two seconds later, the aircraft returned to a wings-level attitude having lost approximately half of its available altitude. The nose pitched back to a flat attitude and the aircraft impacted the ground. The aircraft's engine was heard to rev on the tape about a second after the impact.
HISTORY OF FLIGHT On September 18, 1999, approximately 0920 mountain daylight time, a Pitts (Aero Design Eleven, Inc.) model 11, N11PU, registered to Starting Line Products, Inc., and being flown by a commercial pilot, was destroyed during an in-flight collision with terrain following a loss of control while maneuvering approximately six nautical miles east of Iona, Idaho. The pilot was fatally injured, and a post-crash fire consumed the aircraft. Visual meteorological conditions prevailed and no flight plan had been filed. The flight, which was personal, was to have been operated under 14CFR91, and originated from Fanning Field, Idaho Falls, Idaho, earlier on the morning of the accident. According to deputies from the Bonneville County Sheriff's Department, a video crew, hired by the pilot, had just terminated videotaping the aircraft before the accident sequence. A passer-by, however, had videotaped the accident including about five minutes of maneuvers prior to the crash. A copy of this videotape was reviewed and showed the following events: The aircraft was videotaped executing two sets of maneuvers which were identical with the exception of the recovery at the end of the second set. In the second routine, the aircraft was observed to initiate a series of two full aileron rolls (counter-clockwise when viewed from behind). The rolls were commenced out of a shallow dive followed by a slight nose up pitch from an altitude of not more then 100-200 feet above ground on an approximate northbound heading (refer to still video image #1). The second full aileron roll was immediately followed by two consecutive snap rolls (clockwise when viewed from behind). In the first set of maneuvers, the second snap roll recovery was completed as the aircraft rolled into a wings level, upright attitude and little altitude was lost. In the second set of maneuvers, the second snap roll recovery was completed as the aircraft's right wing reached a 90 degree right wing down attitude, or approximately 90 degrees later than in the first maneuver. The aircraft's nose was observed pitched down more than 30 degrees below the horizon at this point (refer to still video image #2). The aircraft was observed to remain in a 90 degree right-wing down attitude as it descended, losing approximately 50% of its altitude before rolling wings level about one to two seconds later (refer to still video image #3). The aircraft was then observed to continue descending wings level with the nose pitching up to and remaining at a relatively flat attitude until ground impact (refer to still video image #4). The aircraft's engine could be heard on the video recording during the maneuvers and the sound of an engine 'revving" was heard about one second after the aircraft impacted the terrain. The individual videotaping the aircraft was estimated to be within one-half mile of the accident site. PERSONNEL INFORMATION The pilot's total flight experience was based upon information provided in mid-July of 1999 at the time of an aircraft insurance policy renewal. At that time, he reported to the insurer a total of 1,142 hours (300 hours within the last 12 months). Additionally, he reported 230 hours in the two-place Pitts S-2B, and 66 hours in the single place Pitts S-1-2B. AIRCRAFT INFORMATION N11PU, a single-place, Pitts (Aero Design Eleven) model 11, was equipped with a Textron Lycoming IO-540-X engine, which, according to the airframe logbook, had been modified by Barrett Performance Aircraft. The logbook also showed that on the same date as the engine installation (02/23/96) a Hartzell, three-blade, composite propeller had been installed. The airframe logbook showed a conditional inspection having been signed off on 04/01/99 at a tach time of 231.2 hours (601.2 hours total time in service). The engine logbooks showed a total time in service of 446.6 hours at the 231.2 hour tach time. The engine logbook's last entry was dated 08/18/99 showing an oil change at a tach time of 313.4 hours. A fuel servicing receipt dated 09/18/99 was provided by the fixed base operator at the Idaho Falls airport showing 26.3 gallons of 100 low lead aviation fuel being purchased for aircraft N11PU by the pilot. The receipt showed a time of 0819 for the transaction. METEOROLOGICAL INFORMATION The videotape of the aircraft prior to and at the time of the accident showed day visual meteorological conditions prevailing (refer to photographs). Surface winds recorded at Idaho Falls airport 13 nautical miles west at 0925 hours were calm and the surface temperature was 54 degrees Fahrenheit. WRECKAGE AND IMPACT INFORMATION The aircraft crashed in an open field approximately six nautical miles east of Iona, Idaho. The accident site coordinates were approximately 43 degrees 30.6 minutes north latitude and 111 degrees 47.2 minutes west longitude (refer to CHART I). The first evidence of ground impact was a ground scar approximately 29 feet long and oriented along an approximate north/south bearing line (refer to photograph 5). Two of the propeller's three blades were found at the initial ground impact site and both had separated near the hub. The ground scar terminated and then re-appeared approximately 38 feet north, broadening into an area containing oil spray and burned grass. The aircraft was observed inverted approximately 50 feet north of the beginning of this second ground scar, and had been totally consumed by a post-crash fire (refer to photograph 6). The third propeller blade, also separated at the hub, was subsequently located in a plowed field approximately 235 feet northwest of the aircraft's final resting place and just north of Lincoln Road (refer to photograph 7). The on-site inspector reported that post-crash fire and impact damage prevented him from establishing aircraft control continuity. MEDICAL AND PATHOLOGICAL INFORMATION A post-mortem examination of the pilot was not conducted due to the extensive post-crash fire. Toxicological samples from the pilot were retrieved, however, and evaluation of these samples was conducted by the FAA's Toxicology Accident and Research Laboratory, Oklahoma City, Oklahoma. All findings were negative with the exception of 39 ug/ml of salicylate detected within blood (refer to attached TOX report). ADDITIONAL INFORMATION On-site examination of the wreckage was conducted on September 18 and 21, 1999, by an inspector from the Federal Aviation Administration's Salt Lake City Flight Standards District Office. The inspector reported that he released the wreckage to a personal friend of the pilot's on September 18th.
The pilot-in-command's delayed recovery from a snap roll. A contributing factor was the low altitude at which the maneuver was initiated.
Source: NTSB Aviation Accident Database
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