WPR13FA076

The pilot’s failure to maintain airspeed while attempting a visual climb through a broken cloud layer, which resulted in a stall/spin.

The noninstrument-rated private pilot departed on a cross-country flight in the amateur-built, experimental, turbine-powered airplane. The weather observations indicated two layers of clouds with multiple base layers from 3,600 feet above ground level (agl) and a broken ceiling about 6,000 feet agl. After departure, the pilot told an air traffic controller that he was looking for a hole to get above the clouds. The airplane was likely flying between the two cloud layers as the pilot attempted to find a hole in order to climb above the upper cloud layer. Six minutes after departure, witnesses on the ground observed the airplane descending in a "flat spin." The recorded data from the airplane's onboard electronic flight information system showed that the pilot had climbed to about 6,858-feet pressure altitude (about 5,800 feet agl) while letting the airplane's airspeed decay from about 220 knots to about 76 knots, at which time the airplane entered a spin. The data showed that the airplane completed about seven 360-degree rotations in the spin before it impacted the ground. Further, the data indicated that the airplane's engine was operating normally, and after the first 360-degree rotation, the propeller rpm dropped from about 1,800 to 1,000, consistent with the pilot feathering the propeller. Postaccident examination of the airplane revealed damage consistent with the airplane impacting terrain in a flat spin, and the propeller blades were found in the feathered position. No evidence of any preimpact mechanical discrepancies were found with the airplane's airframe, engine, or propeller that would have prevented normal operation. The medications metoprolol and tamsulosin were detected at unquantified levels in the pilot's muscle and liver. Neither of these medications was likely to have resulted in impairment. The pilot had reported use of tamsulosin to the Federal Aviation Administration (FAA) in May 2011. The use of metoprolol was not reported to the FAA, and it is unknown when the pilot began taking this medication or for what reason he was taking it.

The PFD, MFD, and Engine AirData computer were shipped to the NTSB's Vehicle Recorder Division in Washington, D.C. for recovery of stored flight data. Identical data was recovered from the PFD and the MFD; the Engine AirData computer does not record data. The accident flight was recorded on December 29, 2012, between 1004:42 and 1015:29. A full report, titled "Cockpit Displays – Recorded Flight Data," with plots of the recorded parameters is available in the public docket for this accident. The owner of the company that performed the most recent condition inspection reported that the parameter labeled N2 in the report was propeller rpm. The recording indicated that the airplane departed about 1009:28. The airplane climbed out to the northwest, and about 3,100 feet pressure altitude, it began a turn towards the northeast. It initially climbed to a maximum recorded pressure altitude of 5,238 feet and then descended to 3,868 feet pressure altitude by 1013:35. The airplane then climbed to a maximum recorded pressure altitude of 6,858 feet at 1014:51. After reaching this maximum altitude, it descended to a last recorded pressure altitude of 1,428 feet at 1015:29. After takeoff, the compressor turbine speed designated as N1 was about 95% and remained so until about 1012:24, when the airplane began to descend out of about 5,000 feet pressure altitude. By about 1012:38, N1 decreased to about 79%, the airplane was descending, and indicated airspeed was decreasing through 201 knots. From takeoff until about 1014:57, N2 was about 1,800 rpm. About 1013:40, N1 increased to 94%, as the airplane began to climb out of 3,968 feet pressure altitude, and the indicated airspeed decreased through 189 knots. During the time period from 1013:40 until 1014:41, the pitch attitude increased from 5 degrees to 26 degrees, the airspeed continued to decrease, the altitude increased, the bank angle was less than 5 degrees, and the airplane was heading northeasterly. At 1014:35, the pitch attitude continued to increase to a maximum recorded value of 44.5 degrees; this pitch attitude was reached when the airspeed decreased to 76 knots. At 1014:46, the airplane began to roll left to a bank angle of 38 degrees, which then reduced to 8 degrees left before increasing to a maximum recorded value of 93 degrees left by 1014:53. After 1014:52, the airplane began to descend, and the recorded heading cyclically rotated to the left, making nearly seven 360-degree turns before the recording ended at 1015:29. During the descent, the indicated airspeed reached a maximum value of about 95 knots, and the bank angle varied between about 20 degrees left and right. After the first 360-degree heading change, at 1014:57, N1 and N2 began to decrease, with N1 reaching a minimum value of 64% at 1015:05 and N2 was reaching about 1,000 rpm at 1014:59. At 1015:18, as the airplane passed through about 3,200 feet pressure altitude, N1 began to increase. Over the next 4 seconds, N1 increased to 96% where it remained until the end of the recording. Over the last 30 seconds of recorded flight, N2 fluctuated between about 600 rpm and 1,200 rpm and did not increase when N2 began to increase at 1015:18 The San Diego County Office of the Medical Examiner performed an autopsy on the pilot on December 30, 2012. The FAA's Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma, performed toxicology tests on the pilot. Carbon monoxide and cyanide testing were not performed; no blood was available for testing. The muscle sample tested had 15 mg/dL of ethanol; however, the ethanol was from sources other than ingestion. No ethanol was detected in the heart or the brain. Muscle and liver samples were positive for metoprolol (a prescription beta-blocker used to treat high blood pressure, angina and control heart rate in some arrhythmias) and tamsulosin (a prescription medication used to treat benign prostatic hyperplasia). On his medical certificate application dated May 5, 2011, the pilot reported the use of tamsulosin for benign prostatic hyperplasia. No other medication use was reported. At 0953, the weather conditions at Montgomery Field Airport (elevation 427 feet), located 235 degrees for 10 nautical miles (nm) from the accident site, were as follows: wind 130 degrees at 6 knots; visibility 10 statute miles (sm); cloud condition, overcast at 5,500 feet; temperature 54 degrees Fahrenheit; dew point 39 degrees Fahrenheit; altimeter setting 30.08 inches of Mercury. At 0955, the weather conditions at Miramar Marine Corps Air Station (elevation 477 feet), San Diego, located 250 degrees for 9 nm from the accident site, were as follows: wind 130 degrees at 5 knots; visibility 10 sm; cloud condition, broken at 3,500 feet and broken at 20,000 feet; temperature 55 degrees Fahrenheit; dew point 39 degrees Fahrenheit; altimeter setting 30.07 inches of Mercury. At 1047, Gillespie Field Airport (elevation 388 feet), San Diego, 180 degrees for 5 nm from the accident site, were as follows: wind calm; visibility 15 sm; cloud condition, scattered at 3,600 feet and broken at 6,000 feet; temperature 54 degrees Fahrenheit; dew point 37 degrees Fahrenheit; altimeter setting 30.06 inches of Mercury. This observation indicated two layers of clouds with multiple base layers from 3,600 feet above ground level (agl) and a broken ceiling at 6,000 feet agl. A National Transportation Safety Board Weather Study was performed. The meteorologist reported that satellite data indicated a band of clouds extended from the coast of the Pacific Ocean, over the accident area, to approximately 50 miles inland. The clouds tops over the accident site were from 7,000 to 5,000 feet agl. No cumulonimbus clouds or thunderstorms were indicated over the region at the time. For more information, see the Weather Study in the public docket for this accident. The airplane was a single-turbine-engine-powered, propeller-driven, four seat, pressurized, retractable-gear airplane, which had a special airworthiness certificate (in the experimental category) issued on March 13, 2003. The airplane was built by an individual from a kit manufactured by Lancair International, Inc. It was powered by a Walters M601-EX free turbine engine, serial number 874-039, which had a maximum takeoff rating of 740 horsepower and a continuous rating of 657 horsepower. It had a three bladed, constant speed, full feathering Hartzell propeller. According to the airplane's maintenance logbooks, the most recent condition inspection was completed on November 10, 2011. According to an entry in the airframe logbook dated June 1, 2003, the airplane's builder flight tested the airplane and determined that, at a gross weight of 3,300 pounds, the stall speed in the landing configuration (Vso) was 65 knots; the stall speed clean (Vs) was 80 knots; best angle of climb speed (Vx) was 120 knots; and best rate of climb speed (Vy) was 140 knots. According to a weight and balance document from the airplane's maintenance records dated June 1, 2005, its maximum takeoff gross weight was 3,890 pounds; its empty weight was 2,492 pounds; and its center of gravity range was 86.5 to 94.5 inches. An estimate of the airplane's weight and balance at the time of the accident was calculated; the estimate indicated that the airplane's gross weight was 3,751 pounds, and its center of gravity was 92.4 inches. The cockpit instrumentation included two Sierra Flight Systems Integrated Display Units (IDU), which are Electronic Flight Information Systems (EFIS). These systems provide multifunction display (MFD) and primary flight display (PFD) capabilities. The pilot purchased the airplane on June 6, 2005. The 65-year-old pilot held a private pilot certificate with airplane multiengine land and airplane single engine land ratings. He did not possess an instrument rating. His most recent third-class Federal Aviation Administration (FAA) medical certificate was issued on May 5, 2011. He reporte