NTSB Factual Report

HISTORY OF FLIGHT

On February 25, 2015, about 1624 central standard time, an experimental amateur-built Rose Thunder Mustang, N7TR, was destroyed when it impacted terrain about 2 miles southwest of Helotes, Texas. The commercial pilot received fatal injuries. The airplane was owned and operated by the pilot under the provisions of the 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. The local flight departed from the Boerne Stage Field Airport (5C1), San Antonio, Texas, about 1604.

A witness who lived about 1/2 mile northeast of the accident site reported that he initially heard and then observed the airplane approaching from the northeast and flying to the southwest about 600 feet above ground level. The area the airplane was overflying was unpopulated and near the Government Canyon State Natural Area. When the airplane had flown about 1/2 mile to the southwest, he observed the nose of the airplane go straight up while simultaneously banking to the left. The airplane became fully inverted and then began to descend in a left bank. The witness reported that he expected to see the airplane pull up and level off at its original altitude and depart to the northeast as he had seen the airplane do many times before. However, this time, the airplane continued to descend nearly straight down until he lost sight of the airplane behind a hill and trees, and he heard a "thud" moments later. He reported that the engine sounded like it was producing full power throughout the maneuver and he heard no indication of a loss of engine power. There was no postimpact ground fire. The witness reported that he lived in the same neighborhood as the accident pilot and had previously seen the pilot perform similar maneuvers in the past.

PERSONNEL INFORMATION

The 66-year-old pilot held a commercial certificate with single-engine land, multi-engine land, and airplane instrument land ratings. His pilot's logbook indicated that he had 3,992 total hours of flight time with 58 hours in the accident airplane. He held a second class medical certificate that was issued in April 2014.

AIRCRAFT INFORMATION

The airplane was a single-engine experimental amateur-built Rose Thunder Mustang, serial number GHTM002, manufactured in 1998. It had a maximum gross weight of 3,200 lbs and seated two. It was equipped with a Ryan Falconer V-12 640 horsepower engine. The last conditional maintenance inspection was conducted on May 1, 2014, with a total airframe time of 469 hours. The engine had 140 hours since the last overhaul. The airplane was a scaled down replica of a North American P-51D.

METEOROLOGICAL INFORMATION

At 1551, the surface weather observation at San Antonio International Airport (SAT), located about 12 nm east of the accident site was: wind 320 degrees at 4 kts; visibility 10 miles; clouds few at 2,500 ft; temperature 19 degrees C; dew point 3 degrees C; altimeter 29.81 inches of mercury.

WRECKAGE AND IMPACT INFORMATION

The airplane impacted hard, rocky terrain that contained juniper, mesquite, and oak trees. The debris field was found on a 015 degree magnetic heading. A majority of the fragmented wreckage of the composite airplane was located within 300 feet of the initial impact point. Flight control cable continuity was not established due to the numerous control cable breaks and fragmented control surfaces. All cable breaks exhibited features consistent with overstress failure.

The 640- horsepower Ryan Falconer V-12 engine was found about 730 feet north-northeast from the initial impact point. A visual examination of the engine revealed that the intake manifold, ignition harness, reduction gearbox, and propeller were separated from the engine. All spark plugs were damaged or sheared off during impact. There was no evidence of a preimpact breach in the engine crankcase. The oil pan was separated during impact exposing the power section. The engine including the crankshaft, connecting rods, pistons, and cylinders were examined and there was no evidence of lubrication distress or heat distress.

The four-bladed propeller hub and reduction gearbox was found about 600 feet from the initial impact point. Three of the four wooden blades were separated at the hub, and the fourth blade was separated about 6 inches from the hub. The fractured wooden propeller blades were not located.

Two MoTec M48 Engine Control Units (ECU) A and B and a Vision Microsystems EC100 were sent to the National Transportation Safety Board's (NTSB) Vehicle Recorder Division for examination.

MEDICAL AND PATHOLOGICAL INFORMATION

The autopsy of the pilot was performed at the Bexar County Medical Examiner's Office, San Antonio, Texas, on February 26, 2015. The cause of death was blunt force injuries sustained in the crash of an aircraft. A Forensic Toxicology Fatal Accident Report was prepared by the FAA Civil Aerospace Medical Institute. The results were negative for all substances tested.

TESTS AND RESEARCH

The NTSB Vehicle Recorder Division examined the MoTec M48 ECUs and the Vision Microsystems EC100. It was determined that the Vision Microsystems EC100 was unable to record data relevant to the event and no further work was performed. The examination of the MoTec M48 ECUs revealed the following information:

The MoTec M48 ECU's primary function was to control engine fuel injection and ignition timing. In addition to its primary function, the ECU contained a data logging feature that captured engine parameters and internal ECU faults at a user defined sample rate. The device was set to record at one sample per second and contained 10,638 points of data. It recorded time as elapsed seconds recorded (ESR). The accident flight was identified as the last recorded flight from data point 9,425 to 10,595.

The download of the data from the ECUs indicated that the flight lasted about 19.5 minutes. The engine parameters that were recorded included: engine rpm, throttle position, oil pressure, fuel flow, and barometric reference. The duration of the flight was uneventful until 10,570 ESR, when the barometric reference began increasing, consistent with a descent. The ECU lost power at the last recorded data point of 10,595 ESR. All the engine parameters indicated that the engine was operating at the time that the ECUs stopped recording data.

NTSB Probable Cause

The pilot’s failure to maintain terrain clearance from terrain after initiating an aerobatic maneuver at a low altitude.