Aviation Accident Summaries

Aviation Accident Summary WPR22FA298

Blyn, WA, USA

Aircraft #1

N379DH

CIRRUS DESIGN CORP SR22

Analysis

The instrument-rated pilot was conducting a personal, cross-country, visual-flight-rules (VFR) flight and there was no record of the pilot having a formal weather briefing before departing. Automatic Dependent Surveillance – Broadcast (ADS-B) data and data recovered from the airplane’s multi-function display (MFD) showed that, after departure, the airplane proceeded direct toward its destination on a southerly heading and climbed to an altitude of about 1,100 ft mean sea level (msl). About 13 minutes later, the data showed that the airplane had turned to an easterly heading and then back to a southerly heading as it descended to about 900 ft msl. The data then showed the airplane turning back to the west as it climbed to about 1,460 ft msl. The last recorded data point indicated that the airplane was about 1,363 ft msl located about 930 ft northeast of the accident site. The airplane impacted wooded terrain about 1,286 ft msl and came to rest upright. The wreckage debris path was about 300 ft in length. The impact signatures observed on the trees and wreckage indicated that the airplane impacted trees and terrain in a slightly nose-low attitude. A postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. Recorded engine operating data from the MFD showed that during the last 36 seconds of recorded data, the engine was operating at 2,680 rpm and 25.8 inches of manifold pressure. Recorded weather at the departure airport showed that VFR conditions existed at the time the airplane departed. However, VFR to marginal visual flight rules (MVFR) conditions existed throughout the area, with an area of instrument flight rules (IFR) conditions near the accident site, which included an overcast cloud layer at 900 ft msl. Law enforcement reported that when they arrived at the accident site, they observed a fog bank about 700 ft above the ground and about ¼ mile north of the accident site. A pre-purchase report supplied by a maintenance facility about 2 years before the accident stated in part that “PFD [primary flight display] & MFD Screens showing signs of possible failures.” Another maintenance facility reported that about a month before the accident, the pilot/owner had brought the airplane to their facility for issues involving the PFD and MFD. The representative stated that neither display was working, and that the PFD had a magenta backdrop that indicated “an internal power fail” and the MFD was operative, but the back lighting of the display was not functioning, which made it “virtually impossible to see.” Neither the engine or propeller logbook contained entries pertaining to the repair or replacement of the PFD or MFD, thus it’s likely that neither display was replaced or repaired prior to the accident flight. It’s likely that while en route, the pilot encountered an area of deteriorating instrument meteorological weather conditions (IMC) that obscured terrain and reduced visibility, and as the pilot attempted to turn around and exit the deteriorating weather conditions, the airplane struck trees and the terrain. It’s also likely that the pilot was operating the airplane with known mechanical issues with both the PFD and MFD, which would decrease the pilot’s ability to maintain situational awareness. The pilot's autopsy identified dilated cardiomyopathy, which could result in a sudden impairing or incapacitating cardiac arrhythmia. However, based on ADS-B data and physical evidence, a sudden incapacitating medical event is unlikely to have occurred. The pilot had a history of high blood sugar, and his postmortem urine glucose was consistent with high blood sugar. The absence of detected glucose in his vitreous fluid indicates it is unlikely he was experiencing any severe metabolic disturbance related to high blood sugar at the time of the crash. Both cardiomyopathy and diabetes/prediabetes may be associated with fatigue, but whether such effects were significant for the pilot is unknown. The pilot's toxicology testing indicated that he had used doxepin. The measured levels of doxepin and nordoxepin in heart blood indicate a possibility that he may have been experiencing sedating effects from the medication, but no more-specific conclusion can be drawn, particularly after accounting for the possibility of postmortem redistribution. Whether impairing effects of the pilot's medical conditions or use of medications contributed to the accident could not be determined.

Factual Information

HISTORY OF FLIGHTOn August 10, 2022, about 1459 Pacific daylight time, a Cirrus SR22, N379DH, was destroyed when it was involved in an accident near Blyn, Washington. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. The pilot’s wife reported that the pilot had departed Friday Harbor and intended to fly to Olympia, where he was going to rent a vehicle and drive to West Port, Washington, for a 4-day fishing trip. Recorded ADS-B data showed the airplane departed runway 16 at the Friday Harbor Airport (FHR), Friday Harbor, Washington, about 1445, and proceeded on a southerly heading and climbed to an altitude of about 1,100 ft msl. The data showed the airplane continued south until about 1458:14, when a loss of ADS-B contact occurred. ADS-B contact was reestablished at 1458:51, with the airplane flying on an easterly heading. At 1458:52, the data showed a right turn to a southerly heading and a descent to 900 ft msl at 1459:07, when a second loss of ADS-B contact occurred. As seen in Figure 1, ADS-B contact was reestablished at 1459:13 and showed the airplane on a southerly heading at an altitude of 1,100 ft msl. The last ADS-B target was at 1459:19, at an altitude of 1,400 ft msl located about 0.63 miles northeast of the accident site. Figure 1: ADS-B Track The National Transportation Safety Board (NTSB) Vehicle Recorders Laboratory recovered data from the PFD and MFD that captured the accident flight. The data showed that when ADS-B data stopped the airplane started a right turn from a heading of about 169° magnetic to a 238° magnetic heading over about 11 seconds. Throughout this time, the airplane had climbed to 1,460 ft msl and then descended to 1,363 ft msl at the time of the last recorded data point, located about 930 ft east of the accident site. The data showed that engine parameters were captured every 6 seconds, and that during takeoff, engine power settings had increased to 2,720 rpm and 29.2 inches of manifold pressure. About 1 minute 42 seconds later, engine power settings were reduced to 2,440 rpm and 19.7 inches of manifold pressure. Engine power settings remained consistent at that setting for about 7 minutes 36 seconds, when it was reduced to 2,200 rpm and 16.4 inches of manifold pressure. About 54 seconds later, engine power was increased to 2,280 rpm and 17.6 inches of manifold pressure. The settings remained consistent for about 3 minutes 18 seconds, when engine power was increased. Engine power settings remained increasing over the last 36 seconds of recorded data to 2,680 rpm and 25.8 inches of manifold pressure. The data showed cylinder No. 6’s cylinder head temperature (CHT) had reached 500° F 48 seconds after takeoff power was applied, and remained at 500° F for 10 minutes 18 seconds, when it began to fluctuate between 487° F and 498° F. All of the remaining cylinders’ CHTs remained consistent and varied between 249° F and 283° F. Additionally, exhaust gas temperatures remained consistent among all 6 cylinders throughout the accident flight. AIRCRAFT INFORMATIONThe airplane was equipped with an Avidyne PFD and MFD. Additionally, the airplane had analog gauges, including indicators for airspeed, attitude, altimeter, tachometer, oil temperature, oil pressure, amperage, volts, fuel flow, and fuel pressure. A pre-purchase report supplied by a maintenance facility, dated December 14, 2020, stated in part that “PFD & MFD Screens showing signs of possible failures.” A representative from another maintenance facility reported that in the beginning of July 2022, the pilot/owner of the airplane had contacted their facility about issues involving the PFD and MFD, to which he advised the pilot/owner to fly the airplane to their facility for inspection. The representative stated that upon arrival, he inspected the displays and found that neither display was working. He noted that the PFD had a magenta backdrop that indicated “an internal power fail” and the MFD was operative, but the backlighting of the display was not functioning, which made it “virtually impossible to see.” The representative added that the pilot/owner asked him if the airplane was able to be flown in the condition it was in, and he had advised the pilot/owner that it was not. Review of maintenance logbooks revealed no entries regarding the repair or replacement of the PFD or MFD. Additionally, no reference to a static system check per CFR 91.111 was observed. METEOROLOGICAL INFORMATIONLaw enforcement reported that when they arrived at the accident site, they observed a fog bank that was about 700 ft above the ground and about ¼ mile north of the accident site. The automated surface observation system (ASOS) located at FHR, at an elevation of 113 ft msl, reported 6 minutes before the accident airplane took off that the visibility was 9 statute miles, with a scattered cloud layer at 800 ft and an overcast cloud layer at 10,000 ft. The automated weather observation system (AWOS) located at the Jefferson County International Airport, Port Townsend, Washington, at an elevation of 110 ft msl, located about 5.5 miles east-northeast of the accident site, reported about 5 minutes before the time of the accident that visibility was 10 statute miles, with an overcast cloud layer at 800 ft. A depiction of the observations from the NWS Aviation Weather Center’s Helicopter Emergency Medical System (HEMS) METAR display with the weather radar overlay is included as Figure 2 with the accident site marked by the red star. The display showed general VFR to MVFR conditions over the area with an area of IFR conditions in the vicinity of the accident site. The station models showed a generally diffluent, or easily dissolving, wind pattern over the area with winds from the northwest in the vicinity of the accident site and from the southeast over the departure airport. Figure 2: NWS Aviation Weather Center’s METAR display at 1510 PDT with weather radar overlaid and approximate accident site. AIRPORT INFORMATIONThe airplane was equipped with an Avidyne PFD and MFD. Additionally, the airplane had analog gauges, including indicators for airspeed, attitude, altimeter, tachometer, oil temperature, oil pressure, amperage, volts, fuel flow, and fuel pressure. A pre-purchase report supplied by a maintenance facility, dated December 14, 2020, stated in part that “PFD & MFD Screens showing signs of possible failures.” A representative from another maintenance facility reported that in the beginning of July 2022, the pilot/owner of the airplane had contacted their facility about issues involving the PFD and MFD, to which he advised the pilot/owner to fly the airplane to their facility for inspection. The representative stated that upon arrival, he inspected the displays and found that neither display was working. He noted that the PFD had a magenta backdrop that indicated “an internal power fail” and the MFD was operative, but the backlighting of the display was not functioning, which made it “virtually impossible to see.” The representative added that the pilot/owner asked him if the airplane was able to be flown in the condition it was in, and he had advised the pilot/owner that it was not. Review of maintenance logbooks revealed no entries regarding the repair or replacement of the PFD or MFD. Additionally, no reference to a static system check per CFR 91.111 was observed. WRECKAGE AND IMPACT INFORMATIONExamination of the accident site revealed that the airplane impacted a heavily wooded area at an elevation of 1,286 ft msl. The first identified point of contact was a freshly topped tree with composite material fragments located near the tree root. The debris path initially extended along an approximate 270° heading for about 300 ft before shifting to an approximate 312° heading, which extended for about 155 ft. All major structural components of the airplane were located within the debris path. Throughout the debris path, numerous trees, 70 to 80 ft in height, were topped. One tree, located adjacent to the fuselage, was stripped of its bark along the eastern side of the tree from about 5 ft above the ground to the area it was topped. The fuselage came to rest inverted on a heading of about 301°. The forward part of the fuselage was fractured in half just aft of the lower part of the windshield. The upper cabin roof was separated and located throughout the debris path. The Cirrus Airframe Parachute System (CAPS) handle was found extended with no securing pin on the separated part of cabin roof structure. The parachute remained stowed within its deployment bag. The CAPS rocket was found secure to its cables, separated from the airframe, and was partially wrapped around the tree with stripped bark. The rocket was not expended. The engine was separated from the engine mount and found inverted within the wreckage debris path. Impact damage to both the PFD and MFD precluded functional testing of either display. Examination of the engine revealed that both magnetos, standby alternator, and starter were separated from their mounts. The upper area of the crankcase had a crack that spanned between the Nos. 5 and 6 cylinders. The Nos. 2-, 4-, and 6- cylinder fuel injectors were pulled away from their respective cylinders. The No. 6 cylinder exhibited impact damage to the cylinder head, and the induction rocker arm and housing were separated. The upper spark plugs, rocker box covers, and fuel pump were removed. The crankshaft would not rotate by hand. All 6 cylinders were examined internally using a lighted borescope and exhibited varying degrees of corrosion. The intake and exhaust valves on cylinders Nos. 1, 2, 3, 5, and 6 were unremarkable. The valves on cylinder No. 4 could not be examined due to the position of the piston. The No. 6 cylinder exhibited no evidence of heat distress or evidence of high cylinder head temperature operation. Six holes were drilled in the crankcase to facilitate internal examination using a lighted borescope. The internal components, including the crankshaft, connecting rods, and pistons were found unremarkable. No evidence of any catastrophic failure was observed. The fuel manifold valve was impact damaged. The manifold valve was disassembled and the internal spring, diaphragm, and screen were intact. The fuel pump remained attached to the engine and the driveshaft was intact. The fuel pump driveshaft rotated by hand. The mixture control arm was impact damaged but moved from stop to stop by hand. The fuel pump was disassembled and found to be unremarkable. The throttle body was impact damaged. The throttle arm moved stiffly from stop to stop with corresponding movement of the throttle plate. MEDICAL AND PATHOLOGICAL INFORMATIONPacific Northwest Forensic Pathologists performed the pilot’s autopsy. According to the pilot’s autopsy report, his cause of death was multiple blunt force trauma and his manner of death was accident. Evidence of dilated cardiomyopathy was identified; his heart was described as enlarged with prominent dilatation of all chambers. The autopsy did not identify other significant natural disease. The FAA Forensic Sciences Laboratory also tested postmortem specimens from the pilot. This testing detected doxepin at 9 ng/mL in heart blood and 23 ng/mL in urine, as well as the doxepin metabolite nordoxepin at 11 ng/mL in heart blood and 9 ng/mL in urine. Sildenafil and its metabolite desmethylsildenafil were also detected in heart blood and urine, as were losartan and amlodipine. Glucose was measured at 771 mg/dL in urine; glucose was not detected in vitreous fluid. HbA1c was measured at 6.4% Doxepin is a prescription tricyclic antidepressant medication that may be used at low doses to treat insomnia or at higher doses to treat depression. A topical form of doxepin is also available for treatment of itching and nerve-related pain. Doxepin is highly sedating and generally carries a warning against driving or operating machinery after use, even in topical form. The plasma elimination half-life of doxepin is about 8-25 hours and impairing effects from bedtime doxepin use can persist into the next day. The FAA states that pilots should not fly while using any sedative or medication that carries a driving or drowsiness warning. Additionally, some conditions treated by doxepin can be impairing; for example, major depression can cause cognitive impairment, particularly of executive function. A pilot’s use of doxepin for any reason is disqualifying. Nordoxepin is an active metabolite of doxepin. Both doxepin and nordoxepin may undergo postmortem redistribution, affecting levels measured in heart blood. Sildenafil is a prescription medication commonly used to treat erectile dysfunction, as a sexual enhancement aid, or in the treatment of certain other conditions. Sildenafil is not generally considered impairing, although the FAA states that pilots should wait 8 hours after using it before flying, to monitor for side effects. Desmethylsildenafil is a metabolite of sildenafil. Losartan and amlodipine are prescription medications commonly used to treat high blood pressure; they are not generally considered impairing.

Probable Cause and Findings

The pilot’s continued operation of the airplane with known mechanical malfunctions with the flight displays, and his continued flight into instrument meteorological conditions, which resulted in an inflight collision with terrain while maneuvering.

 

Source: NTSB Aviation Accident Database

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