History of Flight
At 1714 central daylight time on June 24, 2021, an American Aviation AA-1A airplane, N9261L, was destroyed in an accident near Cleburne, Texas. The pilot and passenger sustained fatal injuries. The flight was conducted as a personal flight under Title 14 Code of Federal Regulations Part 91.
Flight track data indicated that the airplane departed Cleburne Regional Airport (CPT) at about 1658. It flew south, then northeast toward Keene, Texas. After executing a tight left 360° turn over Keene, the airplane proceeded west, overflying CPT, and continued west at an altitude of about 2,600 ft mean sea level (msl) for approximately 3 miles. During the final 10 seconds of recorded data, the flight track showed a hard right turn, immediately followed by a left spiraling descent toward the ground. No air traffic control communications were recorded during the flight.
A witness located about 1/2 mile south of the accident site reported observing the airplane “going straight down,” but did not witness the impact.
An in-flight video recorded on the passenger’s cell phone and uploaded to social media showed the airplane’s left wing, then panned to display the front of the cockpit, and captured the pilot in the right seat. The pilot had his left hand on the control yoke, a tablet connected to the yoke, and a cell phone in his right hand. The canopy was open about 8 to 10 inches. Cockpit instruments indicated the airplane was at about 1,960 ft msl, climbing at 400 to 500 ft per minute, with an airspeed of about 100 to 105 knots. Based on geographical landmarks, the video was recorded approximately 6 minutes after takeoff and 10 minutes before the accident, as the airplane headed northeast toward Keene.
Aircraft Information
The accident airplane was equipped with a plexiglass and aluminum sliding canopy. The canopy moved on inner tracks that slid on outer tracks with Teflon runners, allowing it to be slid forward and aft. A placard on the left-side outer track indicated the ½ open canopy point and stated: “130 MPH MAX WITH CANOPY ½ OPEN. NO FLIGHT WITH CANOPY FULL OPEN.”
A representative of the Grumman Pilot’s Association stated that the airplane could still fly with the canopy fully open, though with a significant increase in drag.
After the accident, the pilot’s father reported that the pilot would fly with the canopy open in warm conditions to increase cockpit airflow but would close it in cold weather. The pilot typically manipulated the canopy himself, without passenger assistance, to ensure equal pressure was applied to both sides for smooth movement. The father noted that the canopy sometimes moved forward during flight, requiring the pilot to adjust it aft using the black screw knob lock.
Wreckage and Impact
The airplane came to rest in a rural field and partially on a gravel road. The initial impact point was marked by an impression in the dirt containing red glass near the outboard tip, consistent with the left wing. The empennage was distorted to the left, and the accident site showed minimal forward momentum. All major components were present at the site.
The sliding canopy frame had separated from the fuselage and was found forward of the right wing; the plexiglass was shattered and scattered. The left side of the canopy frame was bent inboard about 30 inches from the aft end. The left-side canopy track had separated from the fuselage, and its screw knob lock was mostly unscrewed, or loosened, but the lock functioned normally through its full range.
Impact witness marks on the left rear fuselage, under the left rear window, corresponded to the shape of the lower canopy frame and inner tracks. Examination of an exemplar AA-1A revealed that when the canopy was positioned fully aft, the frame and inner tracks aligned with the rear fuselage; when slightly open, the inner tracks did not extend to that area. No preimpact anomalies were found that would have precluded normal operation.
Engine and Data
The engine remained partially attached to the airframe and sustained significant impact damage. The propeller was attached to the crankshaft flange by two bolts. One blade was bent aft at about mid-span without leading edge damage; the other was mostly straight with leading edge gouges and chordwise scratches near the tip. Engine examination revealed no preimpact mechanical malfunctions.
Data from a JPI engine monitor was extracted. Between 1659 and 1709, data appeared normal. At 1709:40, exhaust gas temperatures (EGT), cylinder head temperatures (CHT), oil pressure, rpm, manifold pressure, fuel flow, and horsepower all decreased slightly for about 40 seconds, with a shock cooling rate increase from 0°/min to 25°/min, then back to 0°/min after 48 seconds. This corresponded to the tight left turn over Keene. At 1710:50, parameters leveled off at slightly lower values. At 1713:30, a significant reduction in engine power occurred, shown by a simultaneous rapid decrease in all parameters and a shock cooling rate increase to 42°/min. This corresponded to the left spiral descent. The manifold pressure after 1713:30 was consistent with a closed throttle plate. Fuel pressure remained nominal throughout.