ZENITH STOL CH701

Full Narrative

On December 29, 2023, about 2157 eastern standard time, an experimental amateur-built Zenith STOL CH 701 airplane, N4209W, was destroyed when it was involved in an accident near Marienville, Pennsylvania. The private pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

ADS-B track data revealed that the airplane departed runway 24 at Erie International Airport/Tom Ridge Field (ERI), Erie, Pennsylvania, about 2058, destined for John Murtha Johnstown/Cambria County Airport (JST), Johnstown, Pennsylvania. The flight proceeded generally in an easterly direction about 3,100 ft msl, with some small deviations to east-northeast, then turned to a southeasterly direction, toward JST. At the time of the accident, the flight was operating under visual flight rules, and the pilot was not in communication with air traffic control.

About 90 seconds before the last recorded ADS-B data, weather radar indicated that the airplane flew into an area of light reflectivity that was consistent with developing light snow (figure 1).


Figure 1. The airplane’s ADS-B flight track (white line) overlaid onto an aerial image and base reflectivity weather radar imagery. The flight track ended in the vicinity of the accident site (area circled in red).

About the same time, the airplane began a left turn while flying at an altitude about 2,900 ft msl, or about 1,300 ft agl. The left turn tightened, and the airplane climbed to about 3,350 ft msl, then began a steep descent in a tight left spiral. The last ADS-B-observed position of the airplane at 2156:56 showed that it was at an altitude of 2,150 ft msl. The airplane impacted trees and terrain about 450 ft northwest of that final ADS-B position (figure 2).


Figure 2. ADS-B data (yellow line) showing final portion of the flight and wreckage area (red shaded box).

The pilot held a private pilot certificate with ratings for airplane single-engine land. He did not hold an instrument rating. Electronic logs showed that between July 2017 and March 2022, the pilot logged 124.6 flight hours, of which 28.2 hours were logged at night. Complete pilot logbooks were not located. At the time of his last medical examination on January 31, 2023, the pilot reported that he had accumulated 5,300 total hours of flight experience.

According to FAA airworthiness and registration records, the airplane was manufactured in 2006 and registered to the pilot in 2017. No airframe, engine, or propeller maintenance logs could be located. The accumulated airframe time could not be determined. A statement from the fixed-base operator at ERI, where the accident flight originated, stated that they serviced the airplane with 24.5 gallons of 100LL aviation fuel on December 29, 2023. Fuel records indicated that the fuel tanks were topped off.

At the time of departure, the reported weather conditions at ERI included wind from 210° at 7 kts, a broken ceiling at 1,700 ft msl and an overcast ceiling at 4,200 ft msl, and 10 statute miles visibility. At the same time, the weather conditions at JST, which was located about 70 miles south of the accident site, included wind from 260° at 8 kts and an overcast ceiling at 1,300 ft msl. About one hour later, the destination airport reported the ceiling as overcast at 900 ft msl.

Pilot reports within 75 miles of the accident site during the four-hour period surrounding the accident time indicated light to moderate icing at or below 7,000 ft. ?Terminal Aerodrome Forecasts for nearby airports predicted light snow, overcast skies, and visibility reductions around the time of the accident. The National Weather Service’s Area Forecast Discussion issued at 2106 noted mainly marginal visual flight rules conditions with local instrument flight rules conditions due to light snow and mist.

The Automated Surface Observing Station at Dubois Regional Airport (DUJ), Dubois, Pennsylvania, located about 18 miles south-southeast of the accident site, indicated an overcast ceiling at 800 ft agl (about 2,600 ft msl), visibility of 4 statute miles, mist, and a temperature of 1°C at 2153. ?The Automated Weather Observing Station at St Marys Municipal Airport (OYM), St Marys, Pennsylvania, located about 26 miles east of the accident site, reported a ceiling at 1,400 ft agl (about 3,300 ft msl) and visibility of 10 statute miles at 2155.

No SIGMETs or Center Weather Advisories were active for the accident region at the time of the accident. ? However, graphical AIRMETs for mountain obscuration were issued earlier in the day and were valid at the time of the accident.

A High-Resolution Rapid Refresh (HRRR) model sounding analyzed by the RAwinsonde OBservation (RAOB) program estimated a freezing level about 2,000 ft msl, with cloudy conditions between 3,000 and 6,000 ft msl, and light to moderate clear or rime ice between 2,500 and 5,700 ft msl, near the accident location and time.

Review of archived information indicated that the pilot did not request a weather briefing through the FAA’s flight service provider. According to information provided by ForeFlight, a flight planning software provider, the pilot accessed his ForeFlight account and updated his planned route of flight about 1800 on the day of the accident; however, he did not file a flight plan or obtain a weather briefing through the service, and no weather imagery was viewed by his account.

The airplane impacted wooded terrain inside the Allegheny National Forest. The initial point of impact was the top of a 70-ft-tall hardwood tree, and the airplane continued at a 60° descent angle until the main wreckage lodged into another hardwood tree. Both wings and the main landing gear separated during impact. All structural components of the airplane were accounted for at the accident site. The magnetic heading from the initial tree strike to the main wreckage was 140°, and the fuselage was found oriented on a heading of 320°. The entire wreckage path was about 65 ft long and about 25 ft wide. There was no fire, but there was a noticeable fuel odor at the accident site. Postaccident examination of the airplane revealed no evidence of any preimpact mechanical malfunctions or failures or that would have precluded normal operation.

At the time of the pilot’s last aviation medical examination, he reported no medication use and no active medical conditions. Medical records from a hospital system where the pilot was known to have received care in 2020 were requested for a period of 3 years before the accident. The records did not indicate any pertinent medical history.

The FAA Forensic Sciences Laboratory performed toxicological testing of postmortem specimens from the pilot. Methamphetamine was detected at 11,262 ng/g in liver tissue and at 264 ng/g in muscle tissue. Amphetamine was detected at 89 ng/g in liver tissue and at 7 ng/g in muscle tissue. Phenylpropanolamine, ephedrine, modafinil, and modafinil acid were detected in liver and muscle tissue. Sildenafil and desmethylsildenafil were detected in liver tissue and were not detected in muscle tissue. No blood was available for testing.

Methamphetamine is a central nervous system (CNS) stimulant drug. Amphetamine is a metabolite of methamphetamine and is a CNS stimulant. Both methamphetamine and amphetamine are available as federal Schedule II controlled substance prescription medications used to treat attention deficit hyperactivity disorder, narcolepsy, and occasionally obesity. As medicines, the drugs typically carry warnings that they may impair the ability to engage in potentially hazardous activities. The FAA considers methamphetamine and amphetamine to be “Do Not Issue/Do Not Fly” medications. In addition to being used medicinally, methamphetamine and amphetamine may be produced illicitly and abused recreationally. At low doses used as part of appropriate medical treatment, methamphetamine and amphetamine may improve reaction time, cognitive function, and fatigue, but may cause people to make higher-risk choices. At higher doses, the drugs may have a variety of impairing effects on psychomotor function, cognition, and perception. Impairment related to methamphetamine or amphetamine use can result from drug or withdrawal effects, with features of CNS stimulation or CNS depression. A measured drug level does not indicate whether a person is experiencing early- or late-phase effects.

Phenylpropanolamine (also known as norephedrine) is a minor metabolite of amphetamine. Phenylpropanolamine also can be used in illicit drug production to make amphetamine. Phenylpropanolamine was previously available in the United States as a nasal decongestant and weight loss ingredient in multiple over-the-counter and prescription products. In 2000, the US Food and Drug Administration requested that all drug companies discontinue marketing products with phenylpropanolamine for human use, due to a small increased risk of brain bleeding.

Ephedrine is a common starting chemical for illicit methamphetamine production. Ephedrine is also a medication that may be used to help relieve wheezing and nasal congestion, and it is a component of some asthma medications. In the United States, medications containing ephedrine may be sold “behind the counter” with no requirement for a prescription. Ephedrine is not typically impairing at the low levels associated with appropriate medicinal use.

Modafinil is a prescription CNS stimulant medication that may be used for a variety of reasons, including to treat excessive daytime sleepiness or narcolepsy. Modafinil acid is a metabolite of modafinil. Modafinil is a federal schedule IV controlled substance. Although modafinil used as part of appropriate medical treatment has not been established to have typical impairing effects on psychomotor performance, the drug may carry a warning that any drug affecting the CNS may alter judgment, thinking, or motor skills, and that users should be cautioned about operating an automobile or other hazardous machinery until it is reasonably certain that modafinil will not adversely affect their ability to engage in such activities. According to the FAA medical case review for this accident, modafinil use is unacceptable for pilot medical certification.

Sildenafil is a prescription medication commonly used to treat erectile dysfunction, as a sexual enhancement aid, or in the treatment of certain other conditions, including pulmonary hypertension. Desmethylsildenafil is a metabolite of sildenafil. Sildenafil is not typically impairing, although the FAA states that pilots should wait 8 hours after using it before flying, to monitor for side effects.

According to the FAA Pilot’s Handbook of Aeronautical Knowledge, the visual illusion “graveyard spiral” occurs following a prolonged coordinated, constant rate turn when a pilot may experience the illusion of not turning. When recovering to level flight, the pilot will sense a turn in the opposite direction and will return the aircraft to the original turn direction. Pulling back on the controls without leveling the wings, for example to compensate for a loss in altitude, tightens the spiral and increases the altitude lost.