NTSB Factual Report

HISTORY OF FLIGHT

On May 7, 2011, about 0855 central daylight time, a Woodward Ravin 500 experimental amateur-built airplane, N913RA, owned by a private individual and operated by a private pilot impacted forested terrain shortly after takeoff from Lone Star Executive Airport (CXO), Conroe, Texas. A postimpact fire ensued. Visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted under the provisions of 14 Code of Federal Regulations Part 91. The private pilot and student pilot-rated passenger were fatally injured. The flight was originating at the time of the accident and was en route to Temple, Texas, for the airplane to be displayed at an aviation event.

Per the Air Traffic Control Tower transcript, about 0851:41, the pilot requested and received clearance for takeoff and a right turn on course.

At 0853:48, the pilot reported “we have smoke in the cockpit.” A female voice heard in the background and identified as the student pilot-rated passenger said “we’re on fire”. The tower controller cleared the airplane to land on any runway.

At 0854:57, the pilot said, “I’m trying to reach … [the] runway here so I can make it, I got smoke in the cockpit, but … it’s flying”. The tower controller responded, “That’s fine any runway your choice you’re clear to land, wind one seven zero at eight”.

At 0855:19, the student pilot-rated passenger was heard saying “gear down”. The pilot said “alright”. That was the last voice transmission heard from the airplane.

The CXO tower controller said he cleared the pilot for takeoff on runway 14 and to turn right on course. He said that the pilot had barely made the turn when he reported he had smoke in the cockpit. He then cleared the pilot to land on any runway and gave the pilot the winds as from 160 degrees at 8 knots. The airplane made an approximate 240 degree right turn and crossed back over the departure runway before entering the left downwind leg for runway 14. While on the downwind leg of the traffic pattern, the airplane was observed flying “slow” wings level, at an estimated altitude of 700 to 800 feet above ground level (agl), like it was in slow flight. The pilot had a hot microphone because he heard the female in the airplane say “gear down”. Shortly after hearing that, the tower controller said he saw the landing gear come down. The airplane was about 4,500 feet along the downwind leg when the landing gear was extended. Shortly thereafter, the airplane started a descending left turn towards the closer runway 19. The airplane overshot the extended centerline for runway 19 and then turned sharply to get back to the runway. It then looked like the left wing stalled and the airplane descended left wing and nose low into the trees. When the airplane stalled, it was about 300 feet above the trees. The tower controller said that he never observed smoke coming from the airplane.

The CXO ground controller said he did not see the airplane until it was established on downwind for runway 14 at the southeast boundary of the airport. He said the airplane was below 500 feet agl. He said he heard the student pilot-rated passenger say “gear down”. The ground controller said he saw the airplane abeam and passing through the extended centerline for runway 19 and said as he passed abeam the airplane was really slow. The airplane then went into a left 80-degree bank turn toward the runway. He further stated that there was no altitude to recover and that it looked like the airplane was in a textbook base turn to final stall. The ground controller said he did not see smoke coming from the airplane or flames or any other anomalies except the slow airspeed.

A pilot-rated eyewitness located near the crash site reported hearing what he described as an engine that was “screaming” and varying in RPM. When he saw the airplane, it was flying “very slow” at an estimated altitude of 300 to 500 feet above the ground. As the airplane made a high bank angle turn back towards the airport the witness observed the nose and left wing drop before the airplane went out of sight. Seconds later he heard it impact trees followed by an explosion.

PERSONNEL INFORMATION

The pilot in the left seat, age 70, held a private pilot certificate with a single engine land airplane ratings. According to his wife and a close friend, the pilot would have had his logbook with him in the airplane. No evidence of a pilot logbook was found amongst the airplane wreckage. However, information provided the airplane’s insurer indicated that the pilot had greater than 3,400 total flying hours and about 150 hours in the make and model of airplane.

According to Federal Aviation Administration (FAA) airmen medical records, the pilot held a Third Class medical certificate with the limitation “must wear corrective lenses”, dated June 1, 2010.

The student pilot-rated passenger, age 52, held a student pilot certificate dated December 8, 2005. She also held a Third Class medical certificate with the limitation “must wear corrective lenses”, dated December 8, 2005.

AIRCRAFT INFORMATION

The airplane was a 2009 Harold W. Woodward Ravin 500, serial number 07050013. The airplane was powered by a single Chevrolet LS1 fuel-injected reciprocating engine rated at 300 horsepower.

The airplane was constructed from a kit produced by SA Ravin Aircraft in Pretoria, South Africa. The airplane structure is all composite materials, some parts being glass and others parts, as the wing spars and elevator, being carbon fiber. It is a low wing, 4-place, design with retractable tricycle landing gear and retractable flaps, based on the concept of the Piper Comanche. The first Ravin 500 flew on September 15, 2002.

According to the airplane’s owner, the airplane and engine logbooks would have been in the airplane. No evidence of logbooks was found in the airplane wreckage and the airplane’s owner did not provide an estimate of total hours on the airframe or engine. A copy of the airworthiness certificate showed the airworthiness date of the airplane as July 13, 2009. The owner stated that the airplane underwent a conditional inspection on July 14, 2010.

METEOROLOGICAL INFORMATION

At 0853, the aviation routine weather report (METAR) for CXO was wind 180 degrees magnetic at 6 knots, visibility 10 statute miles, few clouds at 23,000 feet, temperature 68 degrees Fahrenheit (F), dew point 63 degrees F, and altimeter 29.95 inches of Mercury (HG).

WRECKAGE AND IMPACT INFORMATION

The airplane came to rest in an upright position about 1,600 feet out on the extended center line from the approach end of runway 19. The measured impact heading was 200 degrees magnetic.

Preceding the accident site were several broken trees. Several of the fractured tree trunks and branches arrived with the airplane at its final resting place. Trees and foliage in the immediate area surrounding the airplane main wreckage were charred and consumed by fire.

The airplane main wreckage consisted of all of the airplane’s components. The airplane’s structure was charred, melted and consumed by fire. The engine was charred and melted. The propeller blades were broken, charred, and consumed by fire. Flight control cables and bellcranks were confirmed continuous from the cockpit to the remains of the control surfaces.

MEDICAL AND PATHOLOGICAL INFORMATION

Autopsies were performed on the pilot and student pilot-rated passenger by the Montgomery County Forensic Services Department in Conroe, Texas, on May 9 and 10, 2011. Both autopsies showed blunt injuries with associated thermal injuries and smoke inhalation.

Results of toxicology testing of samples taken from the pilot showed 2.24 (ug/ml) Cyanide in Blood (Cavity). According to information provided by the Federal Aviation Administration Bioaeronautical Sciences Research Lab, because of the absence of Carbon Monoxide (CO) the elevated level of Cyanide is likely from the ground fire and smoke inhalation.

Results of toxicology testing of samples taken from the student pilot showed the presence of Diphenhydramine in liver and kidney.

TESTS AND RESEARCH

The engine was examined at Conroe, Texas, on May 9, 2011. The engine was removed from the airframe, suspended by a lift, and pressure washed for inspection. The engine was disassembled and examined. Valve train continuity was established from the propeller shaft throughout the engine. All internal parts were found in their respective positions and did not exhibit signatures of preimpact distress. The propeller speed reduction (PSRU) was removed from the engine and examined. No preimpact anomalies were noted. The electronic control unit (ECU) was thermally damaged and could not be tested. Of the examined components, no abnormalities were found that would have prevented normal operation and production of rated horsepower.

ADDITIONAL INFORMATION

The airplane’s owner stated that in the month leading up to the accident, four of the five flights he’d made had issues where the engine heated up due to improper ventilation. In each case, the owner landed the airplane before the cooling water reached a temperature of 210 degrees F. The owner stated that the LS series engines are very sensitive and at 4,000 rpm, the temperature will climb to 230 degrees F in a matter of seconds if the cooling is not adequate. If the temperature exceeds 230 degrees F, the engine will go into a safe mode and the rpm will be controlled by the engine control unit (ECU). The factory setting for the ECU is around 1,000 rpms. The owner described the airplane as essentially a glider at that power setting. The owner said having experienced this in 2009 he had the pilot’s company set the ECU safe mode to 3,000 rpms. The owner said that flying the airplane in the safe mode was not something he recommended, but the airplane would stay in the air and have enough power to make a safe landing.

The owner’s opinion on the accident was that the engine overheated due to improper air outflow from the cowling not having enough outflow area and no radiator fans. The owner had put exhaust fans on the radiators, but the accident pilot stated they were not needed and removed them prior to the accident flight.

Reportedly, the airplane was in the possession of the accident pilot so he could address the airplane's cooling problems.

NTSB Probable Cause

An in-flight smoke event on takeoff and the pilot’s failure to maintain control of the airplane, which resulted in an aerodynamic stall.