Socorro, NM, USA
N91TX
CONCANNON MILTON RADIAL ROC
The pilot had purchased the airplane the day before the accident and had performed a 30-minute flight with the previous owner. During the purchase inspection, the pilot reportedly expressed concern about the electronic flight display, the autopilot, the mixture control operation, and the boost pump systems. No additional transition training was accomplished in the airplane before the accident flight. Just before the accident, a witness heard abnormal engine sounds (“popping”) and observed the airplane flying erratically in the traffic pattern. While maneuvering toward the airport, the airplane's wings were rocking back and forth, which was consistent with a near stalled condition, before the airplane pitched up then entered a nose-down descent into terrain. The previous owner stated that proper mixture control position and boost pump position was critical during landing, or the engine may stumble or experience a brief shutdown. A postaccident examination of the wreckage did not reveal any evidence of preimpact anomalies. It is likely that the pilot, due to his limited training (30 minutes) in the airplane make and model, was unfamiliar with the unique characteristics of this airplane and its avionics, and that contributed to his failure to maintain airspeed while maneuvering. In a 2012 safety study on "The Safety of Experimental Amateur-Built Aircraft," the NTSB concluded that "purchasers of used [experimental amateur-built] (E-AB) aircraft face particular challenges in transitioning to the unfamiliar E-AB aircraft. Like builders of new E-AB aircraft, they must learn to manage the unique handling characteristics of their aircraft and learn the systems, structure, and equipment, but without the firsthand knowledge afforded to the builder." Thus, the NTSB recommended that the Federal Aviation Administration and the Experimental Aircraft Association "complete planned action to create a coalition of kit manufacturers, type clubs, and pilot and owner groups and (1) develop transition training resources and (2) identify and apply incentives to encourage both builders of experimental amateur-built aircraft and purchasers of used experimental amateur-built aircraft to complete the training that is developed." Postmortem toxicology testing for the pilot indicated positive results for ibuprofen, lorazepam and tramadol. The pilot had not reported any medication on his most recent medical application about 10 months before the accident. Although such medications can have sedating and/or impairing effects, it was not possible to determine to what extent the pilot may have been impaired.
HISTORY OF FLIGHT On September 19, 2011, at 1310 mountain daylight time, a Concannon Radial Rocket experimental amateur-built airplane, N91TX, sustained substantial damage when it impacted terrain while maneuvering near the Socorro Municipal Airport (ONM), Socorro, New Mexico. The commercial pilot and pilot-rated passenger sustained fatal injuries. The airplane was owned and operated by the pilot. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight. The flight departed Dallas Executive Airport (RBD), Dallas, Texas, at 0939 central daylight time. According to the previous owner of the airplane, the pilot and passenger arrived in Mississippi to purchase the airplane on September 17th. On September 18th, the pilot, passenger, and previous owner spent several hours examining the airplane and reviewing its systems. The previous owner and pilot then performed a flight for approximately 30 minutes in which the pilot completed various basic flight maneuvers. The previous owner stated the pilot was very smooth and coordinated on the flight controls. The previous owner then gave the pilot-rated passenger a ride for approximately 10 minutes. For another couple hours after the flights, the group continued to review the airplane. During that time, the previous owner discussed items relative to flight and engine operations during critical phases of flight. The previous owner stated the pilot had concerns with the complexity of the electronic flight information system (EFIS), autopilot system, use of the mixture control, placement of switches, and use of the boost pumps (The pilot owned a Yak 52 with a similar engine, other than there was no mixture control on his Yak 52). The previous owner also stated the pilot had difficulty focusing on where the airspeed and altitude readouts were located on the EFIS display. The previous owner felt the pilot was attentive, asked appropriate questions, and demonstrated an understanding of what was discussed during the day. The pilot and passenger then departed Mississippi approximately 1535 central daylight time en route to the Dallas, Texas, area to stop for an overnight before proceeding to Arizona. The previous owner mentioned he originally planned to spend approximately 10 days with the pilot to perform a detailed inspection and several flights. The pilot indicated he was comfortable and decided to depart from Mississippi on September 18th. The pilot and passenger then flew the airplane to RBD, and spent the night in the Dallas area. After the arrival at RBD, the pilot had the airplane fueled with 16.5 gallons of aviation gasoline. In addition, the pilot asked one of the lineman at the fixed based operator (FBO) for some tools. The lineman observed the pilot and passenger perform some type of repair to the left main landing gear. The airplane departed RBD on the morning of September 19th. Prior to the flight, the passenger contacted flight service and requested the winds aloft along the planned route from RBD to Arizona. When asked what type of airplane, the passenger stated a Cessna 172. Data extracted from a handheld global positioning system (GPS) unit recovered from the wreckage showed a departure from RBD and a descent towards ONM. The recorded flight track ended approximately 2 miles prior to the accident site. One witness, who is a mechanic for a emergency medical services company based at ONM, observed the airplane prior to the accident. He heard a loud pop which brought his attention to the accident airplane. The mechanic saw the airplane heading from east to west toward ONM. As the airplane approached Interstate Highway 25, which runs north and south on the east side of ONM, the airplane turned to the north. During the turn, the airplane appeared to be waving with its wings rocking back and forth. As the airplane continued to the north, the wing waving increased. The witness stated it seemed as if the airplane was losing power and it was getting difficult for the pilot to maintain altitude. As the airplane turned to the west, the airplane was struggling to maintain altitude, wobbling, and waving. The airplane then turned to the south, lost lift, and nosed down. He lost sight of the airplane and observed black smoke a few seconds later. The witness did not see any smoke from the airplane during the flight; however, he heard popping noises from the engine. Another witness, located near the accident site, observed the airplane prior to the impact with terrain. The witness reported observing the airplane in a low altitude which he described as a “crop duster” type operation. The witness observed the airplane briefly pitch nose up and then impact the terrain. PERSONNEL INFORMATION The commercial pilot, who was seated in the front seat position, held single-engine land airplane, multi-engine land airplane, and glider ratings. The pilot reported 4,000 total flight hours on his Federal Aviation Administration (FAA) first-class medical certificate dated November 15, 2010. The pilot reported no use of medications on his medical application. No personal flight records were located for the pilot. On September 16, 2009, the pilot's commercial certificate was suspended for 100 days, and the suspension period ended on December 24, 2009. AIRCRAFT INFORMATION The Concannon Radial Rocket was a two-place composite airplane with fixed conventional landing gear. It was powered by a 400-horsepower supercharged M-14P nine-cylinder radial engine. The airplane was issued an experimental, amateur-built airworthiness certificate on November 10, 2006. The last conditional inspection was completed on June 4, 2011, at a tachometer time of 183.2 hours. The tachometer at the accident site was destroyed; as a result, the total airframe and engine times could not be determined. The aircraft maintenance records, builders log, and other information were partially consumed by the postimpact fire. Portions of the engine records and builders notes were recognizable. According to the previous owner's notes that were recovered from the accident site, the owner recorded, in part: 1. Boost must be on...(remaining words not recognizable due to fire damage). 2. Boost 2 must be on for takeoff and landing (5 minutes). 3. Mixture must be full rich for takeoff, landing, rapid throttle movements. 4. Failure to do #2 and #3 may result in engine stumble or brief shutdown. METEOROLOGICAL INFORMATION At 1315, the ONM automated weather observing system reported the wind from 140 degrees at 9 knots, clear sky, temperature 28 degrees Celsius, dew point 5 degrees Celsius, and an altimeter setting of 30.24 inches of Mercury. WRECKAGE AND IMPACT INFORMATION The accident site was located on a rocky embankment adjacent to an interstate highway on/off ramp approximately 1 mile northeast of ONM. Postaccident examination of the accident site revealed the airplane impacted the lower portion of the embankment and came to rest on the upper portion of the embankment next to the on/off ramp roadway. The wreckage debris path was orientated on a 185 degree heading. The airplane was consumed by a postimpact fire. The main wreckage consisted of the fuselage, both wings, engine, and empennage. Portions of the main landing gear and the underside of the fuselage were found between the initial impact point and the main wreckage. The cockpit/cabin area was destroyed by fire. The instrument panel was destroyed, and the instrument face plates were unreadable. All of the flight control surfaces were located with the main wreckage. Flight control continuity was not established due to fire damage. All flight control surfaces remained partially attached to their respective airframe positions. No flight control anomalies consistent with a preimpact failure or malfunction were noted. The left flap actuator was extended, which was consistent with the flap control surface extended, and the right flap actuator was consumed by fire. The three-bladed wooden propeller hub remained attached to the engine. Two of the blades were separated at the hub and were found splintered into several pieces within the debris field. The outboard section of the third blade was separated and splintered. The leading edges of the blades displayed gouges and large dents. The engine remained attached to the mount, and the mount remained attached the firewall. The engine and components displayed thermal damage, and the fuel lines were consumed by fire. The propeller governor, right magneto, fuel pump, and fuel servo remained attached to the engine. They sustained thermal damage. The starter, starter ring gear, and the left magneto were separated. The fuel servo valve was found in the full throttle position and free to rotate. The cockpit to engine controls remained attached to the propeller governor, mixture and throttle levers. The fuel servo was removed, and the fuel screens were clear of debris. The fuel servo mixture valve was not free to move. The fuel pump was partially removed, and the fuel pump drive shaft was intact. All fuel lines were found attached to their respective components. MEDICAL AND PATHOLOGICAL INFORMATION The University of New Mexico Office of the Medical Investigator completed an autopsy on the pilot and passenger. Cause of death for both was listed as multiple blunt force and thermal injuries. Toxicology specimens of the pilot were retained for testing by the FAA Toxicology and Accident Research Laboratory, Oklahoma City, Oklahoma. The Bioaeronautical Research Science Laboratory, FAA, Oklahoma City, Oklahoma performed a postmortem toxicology of specimens from the pilot and passenger. Review of the toxicology report for the pilot revealed the following drugs: Ibuprofen detected in Urine 2.203 (ug/mL, ug/g) Lorazepram detected in Urine Blood (Heart) unsuitable for analysis of Lorazepam 2.293 (ug/mL, ug/g) Tramadol detected in Blood (Heart) Tramadol detected in Urine Review of the toxicology report for the passenger revealed the following drug: Lorazepam detected in Urine No carbon monoxide, cyandide, or ethanol were detected in either occupant. ADDITIONAL INFORMATION In a 2012 safety study on "The Safety of Experimental Amateur-Built Aircraft," the NTSB concluded that "purchasers of used [experimental amateur-built] (E-AB) aircraft face particular challenges in transitioning to the unfamiliar E-AB aircraft. Like builders of new E-AB aircraft, they must learn to manage the unique handling characteristics of their aircraft and learn the systems, structure, and equipment, but without the firsthand knowledge afforded to the builder." Thus, the NTSB recommended that the Federal Aviation Administration and the Experimental Aircraft Association "complete planned action to create a coalition of kit manufacturers, type clubs, and pilot and owner groups and (1) develop transition training resources and (2) identify and apply incentives to encourage both builders of experimental amateur-built aircraft and purchasers of used experimental amateur-built aircraft to complete the training that is developed."
The pilot's failure to maintain adequate airspeed during the visual approach to the runway, which resulted in an aerodynamic stall. Contributing to the accident were the pilot’s lack of experience in the airplane make and model and the possible sedating effects of medication.
Source: NTSB Aviation Accident Database
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