Aviation Accident Summaries

Aviation Accident Summary ANC96FA099

ANCHORAGE, AK, USA

Aircraft #1

N9297H

Rotorway EXEC 90

Analysis

The pilot had purchased a completed but disassembled helicopter kit from another builder. There was no information in the airplane's records to show that a construction log or inspection log was kept. Training records from the kit supplier show that the pilot had received 7.5 hours of training in the helicopter at the factory school. A video tape of the helicopter just prior to the accident shows the pilot using large cyclic inputs to maintain control during hovering practice. The helicopter is also filmed doing touch-and-go landings. The operating limitation issued by the FAA did not authorize touch-and-go landings at Merrill Field. While the helicopter is on the downwind leg of the traffic pattern, the video tape shows that the nose pitches up and the helicopter rolls to the right slightly. It remains in that position for approximately 1 second. The nose pitches down and the helicopter rolls to the left and descends to the ground out of control. The helicopter blades found installed on the helicopter did not meet service bulletin criteria; the pilot had purchased a complete set of mandatory service bulletins.

Factual Information

HISTORY OF FLIGHT On July 15, 1996, at 2307 Alaska daylight time, a skid equipped, homebuilt helicopter, a Rotorway Exec Model 90, N9297H, registered to and operated by the pilot, pitched up, rolled left, and nosed down into the ground from an altitude of approximately 800 feet. The pilot was performing practice takeoff and landings and was on the downwind leg of the traffic pattern for runway 24 at Merrill Field, Anchorage, Alaska. The personal flight was operating under 14 CFR Part 91. No flight plan was filed and visual meteorological conditions prevailed. The certificated private pilot, airplane rating only, was fatally injured. The helicopter was destroyed by post impact fire. According to a video tape provided by the pilot's son, the helicopter was on the downwind leg. When the helicopter was abeam the intended point of landing, the nose pitched up and then leveled off. The helicopter then rolled approximately 90 degrees to the left, nosed down, and crashed into a school playground. INJURIES TO PERSONS The pilot, the sole occupant, was fatally injured. No one on the ground was injured. DAMAGE TO AIRCRAFT The helicopter was involved in a post impact fire which consumed much of the fiberglass composite structure, much of the aluminum skin, and other soft materials. PERSONNEL INFORMATION The pilot held a private pilot certificate with an airplane single engine land rating. The certificate did not show he was issued a rotorcraft rating. He was also issued a repairman certificate for the Rotorway, Model Exec 90, serial number 5131, helicopter. The date of issue was September 12, 1995. According to excerpts from the pilot's logbook and Rotorway training records, the pilot had received 7.5 hours of flight time in the Rotorway Exec 90 helicopter while attending the Rotorway factory flight training school. According to Rotorway training records, the pilot completed the Phase I training program and had started Phase II. The Rotorway course outline, Phase I, covers hovering maneuvers and other subjects related to construction of the helicopter. Phase II deals with flight maneuvers required to pass the private pilot rotorcraft-helicopter rating flight examination. AIRCRAFT INFORMATION N9297H, a Rotorway Exec Model 90 helicopter, was originally purchased by Mr. Stanley Adams of London, Ontario, Canada. During an interview with Mr. Adams, he stated that he built the helicopter but never flew it. He sold the helicopter to the pilot on April 26, 1995. The bill of sale indicates that the helicopter was not completed. Mr. Adams stated that he disassembled the helicopter before shipping it to the pilot. Advisory Circular AC 20-27D, paragraph 11 (c ), states the following: The applicant should be prepared to furnish the following to the FAA Inspector or DAR: Evidence of inspections, such as logbook entries signed by the amateur builder, describing all inspections conducted during construction of the aircraft in addition to photographic documentation of construction details. Examination of the helicopter records, provided by the family, did not produce any information such as a construction log or photographs depicting the construction, assembly, or inspection of the helicopter. A logbook entry in the front of the logbook identifies the builder as the pilot. A subsequent logbook entry indicates that on September 8, 1995, Mr. John Wakefield, a certificated aviation mechanic, Inspection Authorization number 1628982, inspected the helicopter and found it to be in an airworthy condition. According to 14 CFR Part 21.193 Experimental certificates: general. An applicant for an experimental certificate must submit the following information: (a) A statement, in a form and manner prescribed by the Administrator setting forth the purpose for which the aircraft is to be used. (b) Enough data (such as photographs) to identify the aircraft. (c) Upon inspection of the aircraft, any pertinent information found necessary by the Administrator to safeguard the general public. The helicopter was issued an experimental, special airworthiness certificate on September 12, 1995. Operating limitations were attached which defined the operating area in accordance with 14 CFR Part 21. The FAA was not able to provide any information, nor are they required to keep any information, pertaining to what records were provided to the inspector to ensure the pilot/builder's compliance with 14 CFR Part 21 and Advisory Circular 20-27D. On July 10, 1996, the pilot made an entry in the aircraft log book stating that he certified the helicopter for safe operation. The signature was identified as the pilot's, however, the certificate number entered in the logbook does not match the Repairman certificate number issued on September 12, 1995. On July 12, 1996, an attachment was added to the operating limitations which allowed the pilot to fly the helicopter from Merrill Field, Anchorage, Alaska, to Birchwood, Alaska, in a 300 foot wide corridor centered on the Glenn Highway. According to Mr. Dave Campbell, FAA Maintenance Inspector, this was issued to allow the pilot to fly the helicopter to the Birchwood Airport. The pilot stated that he would have to disassemble the helicopter otherwise, which would require him to re-rig the controls and re-track the main rotor blades. Birchwood airport was the assigned operating area. There were no operational limitations or specifications authorizing the pilot to perform traffic pattern or stop and go operations at Merrill Field. METEOROLOGICAL INFORMATION The accident occurred during the hours of daylight at 2307 Alaska daylight time. The official sunset for that day occurred at 2309 on an azimuth of 319.3 degrees. The sun was 0.2 degrees above the horizon. The video tape shows that it was still daylight when the accident occurred. COMMUNICATIONS The pilot was communicating with Merrill Tower while performing the takeoff and landings. There was no transmission to indicate a problem prior to the in flight upset. WRECKAGE AND IMPACT INFORMATION The helicopter crashed into the playground of Airport Heights Elementary School located near the intersection of 16th and Alder, Anchorage. The helicopter's flight path was on the downwind leg along 15th avenue, at a point where the road turns into DeBarr road. The road aligns with 060 degrees. The helicopter's debris path aligns with 090 degrees. The debris path consisted of pieces of plexiglas and fiberglass material which was recovered from the roof of Charter North Hospital, located at 2530 DeBarr Road, Anchorage. Witnesses stated they saw pieces depart the helicopter while it was flying. Examination of the helicopter wreckage showed that all mechanical components of the helicopter were present at the accident site. Plexiglas and cockpit door material were recovered along the flight path approximately 400 feet from the wreckage. The helicopter wreckage was resting inverted. The main rotor blades, tail rotor blades, tail boom, control tubes, and rotor head assembly were located at the crash site. One main rotor blade spar was broken approximately 5 feet 10 inches outboard from the blade root and remained attached to the rotor hub. That section of rotor blade was curled downward toward the underside of the rotor blade. The remaining portion of that blade was located close to the rotor head. It was curved in the same direction as the section of blade still attached to the rotor hub. The rotor system static stops were examined. Both static stops were bent and crushed. The skids were aligned with 120 degrees magnetic. The alignment of the cockpit could not be determined due to the damage. The ground surrounding the wreckage showed that 30 feet prior to the main wreckage, an impact mark, which measured the same length as a single rotor blade, was aligned lengthwise with 120 degrees. The debris in the immediate area and leading up to the main wreckage consisted of plastic and fiberglass material and pieces identified from the cockpit. FIRE According to the video tape provided by the pilot's son, no fire was visible while the aircraft was in-flight or in the descent preceding the crash. There was a post impact fire. MEDICAL AND PATHOLOGICAL INFORMATION According to the toxicological report provided by the FAA's Toxicology Laboratory, there was no carboxyhemoglobin, cyanide, or ethanol detected in the pilot's blood. However, levels of diphenhydramine, pseudoephedrine, and phenylpropanolamine were detected in the pilot's blood and liver fluid. TESTS AND RESEARCH The video tape, filmed and provided by the son, showed the pilot flying the helicopter for approximately 40 minutes prior to the accident. Different hovering maneuvers are seen in the video tape. A view of the cockpit is visible in some parts of the tape. The pilot's hand on the cyclic can be seen. While the helicopter is hovering, there is visible motion of the hand and the cyclic with corresponding movement of the helicopter. The video tape was examined by Mr. Elbert Wolter, President of Rotorway International. He stated that the pilot was using, what he thought to be, excessive control inputs which were late and resulted in a lateral and fore and aft swing. After ten minutes of hovering, Mr. Wolter stated there was an increase in the lateral swinging and porpoising and loss of altitude. He felt the pilot was also having trouble coordinating throttle changes and heading control. Mr. Wolter described some of the characteristics of the helicopter. He stated that the helicopter was designed to pitch up with a reduction of power, either through the throttle or the collective pitch. The rate of pitch up is dependent upon the rate of power reduction. When the throttle is reduced, the helicopter not only will pitch up but also roll to the right. An increase of the throttle will cause the nose to pitch down and roll left due to torque. Mr. Wolter stated Rotorway recommends that new helicopter students practice 10 to 15 minutes at a time then rest 10 to 15 minutes before performing the next maneuver. Mr. Wolter felt that the pilot had practiced too long without a rest between maneuvers. The video tape shows that the pilot stopped and rested once in the 40 minutes of tape. On the downwind leg of the traffic pattern prior to the accident, the helicopter was 180 degrees abeam its point of intended landing. According to the Rotorway Flight Training Manual, normal procedures dictate that a descent from the downwind altitude to the base leg altitude is started at that point. To begin the maneuver the pilot should reduce collective pitch and reduce throttle to keep from over speeding the main rotor system. The footage on the video tape shows that while the helicopter was on the downwind leg, at an estimated altitude of 800 feet, the nose of the helicopter pitched up. There was also a slight roll to the right. The helicopter remained in this position for less than a second. Then the nose pitched down and the helicopter rolled to the left. The nose continued to pitch down and the helicopter descended out of control. No preimpact mechanical anomalies with the helicopter were discovered during the postaccident inspection. ADDITIONAL INFORMATION According to records maintained by Rotorway International, the pilot purchased a completed helicopter kit from Mr. Stanley Adams of London, Ontario, Canada. The pilot also purchased a complete set of mandatory service bulletins. The helicopter blades found installed on the helicopter did not meet the service bulletin criteria. The pilot operated the helicopter with these blades installed.

Probable Cause and Findings

the pilot's excessive control inputs and the lack of familiarity with the helicopter. A factor associated with the accident was the pilot's failure to follow the prescribed operating limitations.

 

Source: NTSB Aviation Accident Database

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