CESSNA 177B

Full Narrative

HISTORY OF FLIGHTOn April 26, 2023, about 1425 eastern daylight time, a Cessna 177B, N123DS, was destroyed when it was involved in an accident near Watkinsville, Georgia. The private pilot and a pilot-rated passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
The fight departed Leesburg International Airport (LEE), Leesburg, Florida, about 1131 on an IFR flight plan to Barrow County Airport (WDR), Winder, Georgia. Approaching WDR, the pilot established communication with the Atlanta Approach (A80) air traffic controller while descending to 4,000 ft. The controller advised the pilot to inform him when he had the weather and the NOTAMS for WDR and for his approach request. The pilot requested the RNAV Runway 31 approach to WDR. The pilot advised the controller he had obtained the weather conditions at WDR. The controller subsequently instructed the pilot to proceed direct to the CADEB waypoint for the RNAV Runway 31 approach. For traffic management, the controller instructed the pilot to fly heading 040° for radar vectors to the final approach course. The controller then advised him to expect vectors through the final approach course for preceding traffic landing at WDR. The controller then instructed the pilot to turn right to heading 230°. The airplane was observed on radar descending from 4,000 ft and the low altitude alert activated. The controller issued a low altitude alert to the pilot and instructed him to maintain 3,000 ft. The pilot read back the altitude. The controller instructed the pilot to fly heading 270°. There were no further transmissions received from the pilot and radar contact was lost.
 
ADS-B data provided by the FAA showed the airplane entered a right turn consistent with the controller’s instructions; however, the airplane remained in the right turn until contact was lost (see figure). The last ADS-B data point was located about 1,200 ft west of the accident site, about 3,000 ft mean sea level. The elevation at the accident site was about 690 ft.


Figure. ADS-B Flight Track and Wreckage Site PERSONNEL INFORMATIONThe pilot’s logbook was not located. His total flight time was derived from his FAA medical certificate application, dated August 22, 2021.
A hand-written airplane flight log was found with the wreckage and the last page of the log contained an entry for the accident flight. According to the log, the pilot recorded about 52.4 hours flight time in the accident airplane since August 22, 2021. AIRCRAFT INFORMATIONAccording to the airplane’s maintenance records, FAA Airworthiness Directive 2023-02-27 and Textron Aviation Single Engine Service Letter 57-09 Rev. 1, eddy current inspection of the carry-through spar lower surface kick area, was accomplished on April 11, 2023, with no discrepancies found. METEOROLOGICAL INFORMATIONThe closest airport to the accident site was Athens Ben Epps Airport (AHN), Athens, Georgia. At 1451, AHN reported clouds broken at 1,300 ft and overcast at 2,200 ft, with wind from 050° at 11 knots.

The weather at the pilot’s destination airport, WDR, at 1435 included instrument meteorological conditions with a ceiling of 600 ft overcast and wind from 070° at 4 knots.

The accident site was located in a cool airmass between the two fronts and south of a high-pressure ridge. The station models surrounding the accident site depicted northeasterly wind of 10 knots or less, broken to overcast cloud cover, with temperatures in the mid to upper 50's to low 60's degrees Fahrenheit, with several stations over northern and western Georgia, northern Alabama, western South Carolina, and Tennessee reporting light rain. AIRPORT INFORMATIONAccording to the airplane’s maintenance records, FAA Airworthiness Directive 2023-02-27 and Textron Aviation Single Engine Service Letter 57-09 Rev. 1, eddy current inspection of the carry-through spar lower surface kick area, was accomplished on April 11, 2023, with no discrepancies found. WRECKAGE AND IMPACT INFORMATIONThe main wreckage site was located in an open farm field, about 1.2 miles northwest of Watkinsville. The right wing separated in flight, at about the mid-length section of the right flap, and came to rest in a wooded area about 988 ft west of the main wreckage. The separated wing section was close to the coordinates of the last ADS-B data point. The right flap also separated in flight and came to rest in the top of a yellow pine tree, about 90 ft above the ground and 428 ft west of the separated right wing section. The area on the ground between the separated right wing and the main wreckage included numerous windshield fragments and lightweight debris.
The initial ground impact area exhibited a left-wing leading edge imprint, a crater with the separated and buried propeller blades, three ground scars consistent with the left and right main landing gear wheels and the nose wheel, and an imprint consistent with the inboard section of the right wing’s leading edge.
The highly fragmented wreckage was dispersed on a magnetic heading of 137°. Along the debris path, the engine and the lower section of the cockpit came to rest about 36 ft from the initial ground impact point. The empennage came to rest about 22 ft from the engine. The left wing and the top section of the cockpit came to rest about 60 ft from the empennage. The right main landing gear wheel was found about 135 ft from the left wing.
The wreckage was recovered to a salvage facility where an additional examination was performed.
All primary (elevators, ailerons, and rudder) flight control surfaces with their appropriate trim tabs and flaps were accounted for at the wreckage examination. Continuity of the elevator/stabilator and rudder primary flight control cables was confirmed from the cockpit to their respective flight control surfaces.
The elevator/stabilator trim actuator extension was measured and found to be about 1.5 inches, which corresponded to about 10º trim tab trailing edge down.
Continuity of the elevator/stabilator trim control cables was confirmed from the cockpit to the flight control trim surface. Continuity was confirmed by either visual and/or manual manipulation of the cables.
The aileron primary flight control cables were confirmed from the cockpit to their respective flight control surfaces, with cable separations at the right-wing separation and at the cockpit; all cable separations exhibited signatures consistent with tensile overload.
The flap actuator extension was measured and found to be about 4 inches, which corresponded to the fully retracted position.
The damage was consistent with the outboard section of the right wing separating from the airplane in flight. The lower section of the right wing’s main spar separated about 51.5 inches outboard from the wing attachment point. The upper section of the right wing’s main spar separated about 78.5 inches outboard from the wing attachment point. Both separations exhibited signatures consistent with tension overload. With the separated right wing positioned upright on a flat, concrete surface at the recovery facility, the wing was bowed upward near the mid-section.
With the carry-through spar positioned upright, the spar was bowed aft. One of the carry-through spar lightening holes was cracked: the first lightening hole left of the center line, which was cracked up to and along the top of the spar. In the same location, a section of the spar upper forward flange was partially separated and bowed/buckled upward. The lightening hole crack and the spar flange separation both exhibited signatures consistent with tension overload.
A section of the right wing’s inboard leading edge, about 30 inches long, separated from the wing. The leading edge exhibited skin tearing, crushing, and buckling. The leading-edge wing attachment link to the fuselage remained intact and attached to a section of the forward cockpit structure. The leading-edge attachment and the cockpit section were canted aft and up.
The engine was found separated from the airframe and inverted on the grass about 36 ft from the initial impact crater. The following items were impact-separated from the engine and found along the wreckage debris path: the oil sump, carburetor, induction air box, air filter, exhaust muffler and exhaust tubing parts, induction tubing parts, both magnetos, propeller governor, engine-driven fuel pump, starter and the alternator.
Valvetrain continuity was confirmed. Compression and suction were confirmed on three of the four cylinders; the fourth cylinder exhibited impact damage. The carburetor floats exhibited inward hydraulic deformation.
The crankshaft was rotated by means of a tool inserted into the vacuum pump drive pad. Continuity of the crankshaft to the rear gears and to the valvetrain was observed. The Nos. 1, 2, and 4 cylinders exhibited impact damage. Compression and suction were observed from cylinder Nos. 1, 3, and 4. The interiors of the cylinders were examined using a lighted borescope and no damage to the pistons, cylinder walls, or valves was observed. Debris was observed inside the No. 2 cylinder. The Nos. 2 and 4 cylinders were removed to further examine the No. 2 cylinder. No damage other than impact damage was observed to the cylinders, pistons or piston rings. No damage to engine internal parts was observed through the Nos. 2 and 4 cylinder base pads.
The carburetor was impact-separated from the engine and found along the debris path. The carburetor was partially disassembled. The brass floats exhibited inward hydraulic crushing signatures. The float bowl was dry. The engine-driven fuel pump was fragmented and separated from the engine. The pumping section was partially disassembled and no damage to the internal check valves was observed. The upper rubber diaphragm was intact. The lower rubber diaphragm was impact damaged.
The spark plug electrodes exhibited gray coloration and normal wear condition when compared to a Champion Check-a-Plug chart. All four lower spark plugs were impact damaged. The ignition harness was destroyed.
The oil sump was impact separated from the engine. Oil was observed inside the engine. The oil filter was fragmented and crushed. No metallic debris was observed on the oil filter paper element that was visible. The oil suction screen was absent of debris.
The two-blade, constant speed propeller separated from the engine crankshaft. One propeller blade separated from the hub. The other blade remained attached to the hub, which was fragmented. One propeller blade was curved forward about 30° and exhibited leading edge paint abrasion, chord-wise scratches, and trailing edge impact damage. The other blade exhibited paint abrasion, chord-wise scratches, and twisting along the longitudinal axis.
Examination of the wreckage did not reveal evidence of a preaccident mechanical malfunction or anomaly that would have resulted in the in-flight wing separation or normal operation of the engine and propeller. ADDITIONAL INFORMATIONThe FAA Civil Aeromedical Institute's publication, "Introduction to Aviation Physiology," defines spatial disorientation as a “loss of proper bearings; state of mental confusion as to position, location, or movement relative to the position of the earth.” Factors contributing to spatial disorientation include changes in acceleration, flight in IFR conditions, frequent transfer between visual flight rules and IFR conditions, and unperceived changes in aircraft attitude.? 
The FAA’s?Airplane Flying Handbook?(FAA-H-8083-3B) describes some hazards associated with flying when the ground or horizon are obscured. The handbook states, in part, the following:?? 
The vestibular sense (motion sensing by the inner ear) in particular can and will confuse the pilot. Because of inertia, the sensory areas of the inner ear cannot detect slight changes in airplane attitude, nor can they accurately sense attitude changes that occur at a uniform rate over?a period of time. On the other hand, false sensations are often generated, leading the pilot to believe the attitude of the airplane has changed when, in fact, it has not. These false sensations result in the pilot experiencing spatial disorientation. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy of the pilot was performed by the Division of Forensic Sciences, Georgia Bureau of Investigation. The autopsy report was reviewed by the NTSB Investigator-In-Charge. According to the autopsy report, the cause of death was extensive blunt impact injuries, and the manner of death was accident. 

Toxicology testing performed at the FAA Forensic Sciences Laboratory found dextromethorphan, dextrorphan, loratadine, desloratadine, timolol, atorvastatin, acetaminophen, pramoxine, and gabapentin in at least one tested tissue specimen from the pilot; for the gabapentin, only the liver tissue specimen was positive for the pilot. The pilot's testing also detected ethanol at 0.012 g/hg in liver tissue; ethanol was not detected in his muscle tissue. Due to the nature of the accident site, several of the specimens submitted for testing were comingled with those of the passenger.

The detected substances were not substances that are typically impairing, except for ethanol and gabapentin. Gabapentin was also detected in the pilot-rated passenger, who was the pilot’s spouse. Scene photographs of recovered medications revealed that she was prescribed gabapentin. Only one specimen from the pilot tested positive for gabapentin, and reviewed pharmacy records did not show him as being prescribed this medication.

Gabapentin is used for seizure disorders, neuropathies and restless leg syndrome (RLS). It has a high rate of impairing side-effects including dizziness, drowsiness, blurred vision, and sedation. Regular use for any reason is disqualifying.

Although ethanol was detected in the pilot’s liver tissue, it was not detected in his muscle tissue.