DEN08FA140

The inadvertent tail stall and subsequent loss of airplane control as a result of the open canopy. Contributing to the accident was the inadequate emergency procedures provided by the airplane manufacturer and the inadequate design of the canopy latching mechanism.

According to the private pilot receiving instruction, during the flight he became aware of increased airflow on his side of the airplane and noted that the canopy on the flight instructor's side had become unlatched. He mentioned this to the flight instructor and the flight instructor attempted to relatch the canopy. The canopy came completely unlatched and opened to a position of 50 degrees. The nose of the airplane pitched down violently to 60 degrees. The open canopy disrupted the airflow over the empennage resulting in a stalled condition. Neither the private pilot nor flight instructor was able to close the canopy or recover the airplane from the nose low attitude. An examination of the airframe, power plant, and flight control surfaces revealed no anomalies. The latching bolts and latches related to the canopy exhibited scratching consistent with the flexing and movement of the canopy assembly. There is no mechanism to relatch just one side of the canopy without opening the other side of the canopy. According to the pilot operating handbook emergency procedures, in the event that the canopy becomes completely unlatched, the pilot is to ignore the open canopy and wind noise and land the airplane normally. The emergency procedures imply that the airplane is controllable when the canopy is open. The emergency procedures do not address a partially open canopy. Further review of the pilot operating handbook revealed conflicting airspeed information between several chapters in the book and with the markings on the airspeed indicator in the airplane.

HISTORY OF FLIGHT On August 14, 2008, approximately 1100 central daylight time, an Aircraft Manufacturing and Development Company (AMD) CH601XLi special light sport airplane, N451BB, was substantially damaged when it impacted terrain three miles east of Farmersville, Texas. Visual meteorological conditions prevailed at the time of the accident. The instructional flight was being conducted under the provisions of Title 14 Code of Federal Regulations Part 91, without a flight plan. The private pilot receiving instruction sustained minor injuries and the flight instructor sustained serious injuries. The local flight departed Collin County Regional Airport at McKinney (KTKI), McKinney, Texas, approximately 1030. According to a telephone conversation and subsequent written statement provided by the private pilot, he had scheduled a familiarization flight the morning of the accident with the flight instructor in the accident airplane. He stated that the instructor "seemed to be having trouble moving about, so he sat in a chair" while the private pilot and the instructor's wife performed the preflight inspection. Once in the airplane, they lowered the canopy and the instructor visually verified that the left side canopy latch was closed which was accomplished by the private pilot leaning forward. The private pilot reported that he could not see the flight instructor's canopy latch and could not verify that it was "properly latched." During the flight at approximately 2,500 feet mean sea level (msl) and 80 knots, the private pilot "noticed an increase in the airflow through the canopy vent on [his] side." He "noticed that the canopy on the right side was raised." When he brought this to the flight instructor's attention, the instructor attempted to "re-latch" the canopy. He could not recall if this was done by use of the center canopy lever or by pushing down on the right side of the canopy. Both sides opened and the canopy "shot up to about 50 degrees and the nose of the airplane immediately dropped to about 60 degrees" nose down. The private pilot stated that he "closed the throttle," grabbed what he could on the canopy to pull it down, and pulled back on the control stick. He stated that the instructor did the same. The private pilot stated that they were able to break the "dive" but were unable to raise the nose to a straight and level attitude. He "steered" the airplane to an open, plowed field, and the airplane impacted the ground in a 10-degree nose low attitude. According to the written statement provided by the flight instructor, he observed the private pilot student perform a thorough preflight and did not see "anything wrong." He stated that after the "upper air work" had been completed, they began to descend to perform "low air work." The flight instructor stated, "Suddenly, the canopy sprung open." He stated that the private pilot student grabbed the canopy with both hands and he grabbed the canopy with one hand and attempted to fly the airplane with the other hand. He stated that the attitude of the airplane was "dangerous" and he was afraid of "losing control of the airplane." He elected to perform a forced landing to a field. He characterized the airplane as being "very dangerously nose heavy" during the forced landing. According to a follow-up telephone interview with the instructor, his "back was hurting" the day of the accident and observed the private pilot conduct the preflight inspection. He did not note any issues with the student's preflight inspection. After the preflight inspection they boarded the airplane and closed the canopy. He stated that they visually verified that both sides of the canopy were closed prior to flight. The instructor reported that after the right side of the canopy came open, he attempted to close it by "pulling down on it." He stated that they did not attempt to "open and reclose the latch since we could not pull the canopy down." PERSONNEL INFORMATION Private Pilot The private pilot, age 73, held a private pilot certificate with airplane single engine land privileges. He was issued a third class airman medical certificate on April 13, 2004. The certificate contained the limitation "must wear corrective lenses" with "miscellaneous restrictions assigned." The private pilot held a valid driver's license for the state of Texas. According to the Pilot Operator Aircraft Accident Report Form submitted by the private pilot, his last flight review was successfully completed on July 17, 2008, in an IndUS Aviation Thorpedo, also a light sport airplane. He reported 359 hours total time; one hour of which was logged within the last 24 hours and two hours of which were logged in the previous 90 days. The private pilot had logged one hour in the make and model of the accident airplane; the hour during which the accident took place. Flight Instructor The flight instructor, age 65, held a commercial pilot certificate with an airplane single engine land, multiengine land, and instrument airplane ratings. He also held a flight instructor certificate with airplane single engine, multiengine, and instrument ratings. He was issued a second class airman medical certificate in July of 1990. The certificate contained the limitation "must wear lenses for distant - possess glasses for near vision." The flight instructor held a valid driver's license for the state of Texas. A review of the logbook indicated that the flight instructor had not logged flight time in his logbook since February of 1992. In March of 2008, the flight instructor resumed flight logbook entries. According to the logbook he successfully completed the requirements of a flight review on April 12, 2008. His flight instructor certificate was issued on June 17, 2008. The checkride was conducted in the accident airplane. A tally of the flight log revealed that the flight instructor had logged no less than 3,800 hours total flight time; 68 hours of which had been logged in the previous 90 days and 25 hours of which were in the previous 30 days, all in the accident airplane. The logbook revealed no less than 84 hours total time in the make and model of the accident airplane. AIRCRAFT INFORMATION The accident airplane, an Aircraft Manufacturing and Development (AMD) Co., Inc. "Zodiac" CH601XLi (serial number 601-051S), was manufactured in 2008. It was registered with the Federal Aviation Administration (FAA) on a special airworthiness certificate for light sport operations on January 14, 2008. The airplane was powered by a Teledyne Continental Motors O-200-A (82) engine rated at 100 horsepower at 2,750 rpm. The engine was equipped with a two-blade, Sensenich propeller. The airplane was registered to and operated by LCI Solutions Incorporated. The flight instructor used the airplane for the purpose of flight instruction. A review of the maintenance records indicated that a "100 hour" inspection had been completed on July 8, 2008, at an airframe total time of 131.5 hours (tachometer time of 99.7 hours). The airplane had flown approximately 36 hours between the last inspection and the accident. According to the maintenance manual provided by Zodiac, they prescribe 50 hour, 100 hour, 500 hour, and 1,000 hour interval inspections. No evidence of a 50-hour inspection was noted within the airplane maintenance records. According to the flight instructor, he had previous issues with the canopy latching mechanism. The canopy had come open on him in-flight on at least one previous occasion. In addition, he had difficulties in the past properly latching the canopy and opening the canopy, once the canopy was properly latched. He had requested that AMD replace/redesign the latching mechanism. On July 28, 2008, at a tachometer time of 118.2 hours maintenance was performed on the airplane canopy. The maintenance entry stated in part that the canopy latch and seals were lubricated and the system was inspected with no defects noted