ERA12FA052

The pilot’s failure to maintain control of the airplane while flying at low speed, which resulted in a subsequent aerodynamic stall, spin, and impact with terrain. Contributing to the outcome of the accident was the pilot’s decision to operate the airplane with a passenger aboard before fully evaluating the airplane’s handling characteristics after vortex generators were installed.

Before the accident, the pilot had modified the airplane by installing vortex generators onto the airplane's wings. Following the installation, the pilot made an uneventful flight, and, shortly after, he departed on the accident flight. Several witnesses reported seeing the airplane, after a brief flight in the local area, flying directly over the airport at a very low speed. One witness reported that the airplane appeared to enter an aerodynamic stall and a left spin and then impacted the ground. Postaccident examination of the wreckage revealed that the left elevator trim tab upper control cable exhibited significant corrosion and had separated. A detailed examination of the cable and the separation fracture surfaces revealed the presence of significant, unabated corrosion, which had resulted in the cable losing an estimated 90 percent of its strength before ultimately failing in overload. However, it could not be determined whether the failure of this cable occurred before, or as a result of, the airplane's impact with terrain or, what effect, if any, the in-flight failure of this cable could have had on the controllability of the airplane. The wreckage examination did not reveal any other evidence of preimpact mechanical discrepancies or malfunctions that would have prevented normal operation of the engine and airframe components. No evidence was found indicating whether the pilot had intended to perform or had completed a structured flight test of the airplane's performance following the installation of the vortex generators in accordance with its operating limitations (outside of the single, 7-minute solo flight that immediately preceded the accident flight) before operating a flight with a passenger onboard.

HISTORY On October 29, 2011, about 1021 eastern standard time, an experimental Interplane SRO Skyboy, N58784, was substantially damaged when it impacted terrain during an uncontrolled descent near Richards Field (04FA), Miami, Florida. The commercial pilot and the passenger were fatally injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight, which originated from 04FA. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. Witnesses stated that they observed the pilot and the passenger performing maintenance and installing vortex generators on the wings of the accident airplane for the two weeks preceding the accident flight. On the morning of the accident flight, witnesses observed the accident pilot preparing the airplane before he departed on a brief solo, local flight in the vicinity of 04FA. During the flight, the accident flight passenger spoke with the pilot via radio, and the pilot advised her that the airplane was performing in a satisfactory manner. The pilot subsequently returned to the airport uneventfully, and advised witnesses on the ground that the airplane was "flying fine." The pilot and passenger then departed on the accident flight, and after flying in the local area, returned to the vicinity of 04FA. Several witnesses observed the accident airplane as it overflew 04FA at an estimated altitude between 350 and 3,000 feet agl. One witness recounted that the airplane appeared to enter an aerodynamic stall, which was followed by a second stall from which the airplane did not recover. The airplane then began spiraling towards the ground in a corkscrew-like descent. Several of the witnesses then responded to the accident site in order to provide assistance. They reported that both the pilot and passenger were wearing their restraints. PERSONNEL INFORMATION The pilot held a commercial pilot certificate with ratings for airplane single- and multi- engine land, and instrument airplane. He was issued a Federal Aviation Administration (FAA) third-class medical certificate on April 28, 2009, with a limitation of "must wear corrective lenses for near and distant vision." He reported that he had accumulated 2,200 total hours of flight experience at that time. He also held a mechanic certificate with ratings for airframe and powerplant. His personal flight logs were not recovered. AIRCRAFT INFORMATION The high-wing airplane was of a tube and fabric construction, and featured two-place, side-by-side seating. The airplane was equipped with dual flight and engine controls. The airplane was powered by a Rotax 912ULS reciprocating engine that was mounted in a pusher configuration behind and above the airplane's cockpit and wings. According to archived FAA airworthiness records, the airplane was issued a special airworthiness certificate in the experimental category for the purpose of exhibition. The airplane was issued operating limitations on April 16, 2004, which included the following limitations for flights during Phase I (initial flight test) and Phase II (flights outside the flight test area): … 14. The cognizant FSDO [Flight Standards District Office] must be notified, and its response received in writing, prior to flying this aircraft after incorporation of a major change as defined by FAR 21.93. …. 20. No person must operate this aircraft unless within the preceding 12 calendar months it has had a condition inspection performed in accordance with the scope and detail of appendix D to part 43, or other FAA-approved programs, and was found to be in a condition for safe operation. This inspection will be recorded in the aircraft maintenance records. The following limitations were applicable to all Phase II flights: 3. All proficiency/practice flights must be conducted in the geographical area described in the applicant's program letter and any amendments to that letter, but no portion of that area will be more than 150 nautical miles from the aircraft's home base airport. An exception is permitted for proficiency flying outside of the area stated above for organized formation flying, training, or pilot checkout in conjunction with a specific event listed in the applicant's program letter (or amendments). The program letter should indicate the location and dates for this proficiency flying. 5. The owner/operator of this aircraft must submit an annual program letter update to the local FSDO that lists airshows, fly-ins, etc., that will be attended during the next year, commencing at the time this aircraft is released into Phase II operation. The list of events may be amended, as applicable, by a letter or fax to the FSDO prior to the intended operation amendments. A copy of the highlighted aeronautical chart, when applicable, must be carried aboard this aircraft and be available to the pilot. 8. No person may be carried in this aircraft during the exhibition of the aircraft's flight capabilities, performance, or unusual characteristics at air shows, or for motion picture, television, or similar productions, unless essential for the purpose of the flight. Passengers may be carried during flights to and from any event outlined in the program letter or during proficiency flying, limited to the design seating capacity of the aircraft. No current or archived program letters could be located during the course of the investigation. Additionally, a review of FAA documents from the two FSDOs closest to the accident site showed no evidence that the either of the offices had been provided with a program letter update detailing any events the airplane would have planned to attend, nor were any records notifying the offices of major changes to the airplane. According to FAA registration records, the pilot purchased and registered the airplane in 2004. Registration records and witness statements indicated that the accident pilot transferred ownership of the airplane to another individual about 6 months prior to the accident. The new registered owner stated that the pilot continued to fly and perform maintenance on the airplane, and also held the airplane's maintenance records. Review of the airplane's "Daily Operational Records" showed an entry dated May 12, 2004, certifying that the required flight test hours had been completed. Additional flights were logged in the record through July 15, 2005. According to the "Operational Record of Periodical Checking," several entries between April 2004 and March 2005 noted the installation of a replacement engine, installation of a transponder and altitude encoder, as well as periodic maintenance to the engine. No subsequent entries or other documents were found detailing any maintenance after March 26, 2005, nor were any maintenance records discovered that documented the completion of the prescribed 12 calendar month condition inspection. Additionally, no maintenance documentation was found relating to the installation of vortex generators, nor could any information documenting their origin or applicability to the airplane. No documents were recovered, nor were any witness statements provided, to suggest that the pilot had a structured plan in place to flight test the recently-installed vortex generators and document their effects on the airplane's performance. METEOROLOGICAL INFORMATION The weather conditions reported at Kendall-Tamiami Executive Airport (TMB), Miami, Florida, located 7 miles northeast of the accident site, at 1053, included wind from 200 degrees at 9 knots, gusting 16 knots, visibility 10 statute miles, few clouds at 2,000 feet, temperature 28 degrees Celsius (C), dew point 24 degrees C, and an altimeter setting of 29.87 inches of mercury. FLIGHT RECORDERS The airplane was not equipped with any flight data recording devices, nor was it required to be; however, a Garmin GPSMAP 496, handheld GPS receiver was recovered from t