History of Flight
On November 16, 2018, at approximately 1546 mountain standard time, an experimental, amateur-built Zenith Zodiac 601XL airplane, registration N322JL, was substantially damaged in an accident near Overgaard, Arizona. The pilot and a pilot-rated passenger were fatally injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
According to a family member, the pilot and his son had planned a multi-leg journey from Fullerton Municipal Airport (FUL) in Fullerton, California, to Orange Port, Florida. On the morning of the accident, they departed FUL and flew to Lake Havasu City Airport (HII) in Lake Havasu City, Arizona. After refueling at HII, they departed, intending to stop for the night at Mogollon Airpark (AZ82) in Overgaard, where the pilot owned a hangar. The family member noted that the pilot had previously flown into AZ82.
Flight data indicated the airplane turned onto final approach for runway 21 at AZ82. While on runway heading, about half a mile from the approach end, the airplane was approximately 100 feet above ground level at an airspeed of about 62 knots. The flight track then showed the airplane flying low, with airspeed increasing to about 70 knots. The final two data points indicated a slight right turn, ending near the accident site.
Several witnesses in the area reported hearing a loud thud or feeling a vibration around the time of the accident. The wreckage was discovered by nearby homeowners about one hour later, located between residential hangars near the approach end of the runway.
Aircraft Information
The airplane was a kit-plane design optimized for the sport-pilot and light-sport categories. Its published stall speed with flaps down was about 38 knots (44 mph), and its optimum published best glide speed was about 65 knots (74 mph).
Meteorological Information
A privately owned weather station near the approach end of runway 21 recorded a peak wind of 6 knots from the south around the time of the accident.
Wreckage and Impact Information
Examination of the accident site revealed the first identified point of contact was the top of an 80-foot-tall tree on the direct centerline of runway 21, approximately 1,500 feet from the runway threshold. A broken tree limb and a wingtip light assembly were found near this point. About 226 feet further, a wing impact mark and cuts consistent with rotating propeller blades were found on the roof of a house. A propeller blade was discovered in several sections approximately 170 feet from the house. The airplane then struck a second tree before impacting the ground in a taxi area between houses. The empennage separated from the main wreckage and remained lodged in the second tree about 20 feet above ground. The main wreckage came to rest inverted, with leading-edge impact damage to the right wing and buckling to both wings. The fuselage was twisted, and the engine remained partially attached. Fuel was drained from the right wing during wreckage recovery.
A postaccident examination of the airframe and engine found no evidence of preimpact mechanical malfunctions or failures that would have precluded normal operation.
Additional Information
The Federal Aviation Administration Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25B) notes that an upsloping runway or terrain can create an illusion that the aircraft is at a higher altitude than it is, potentially leading a pilot to fly a lower approach. Downsloping terrain has the opposite effect.
Tests and Research
During the investigation, three low approaches were flown into AZ82 to replicate the accident flight. The Visual Approach Path Indicator (VAPI) was visible to the left of the runway threshold.
An airplane performance study showed that the airplane initially intercepted the runway heading slightly above a 3° glide path. It then increased its rate of descent, descending below the 3° glide path. About 3,000 feet from the displaced threshold, it arrested its descent but did not regain the 3° glide path before descending again. The final ADS-B return was 1,200 feet from the displaced threshold, approximately level with it.
During the final descent, the airplane's calibrated airspeed increased from 60 knots to over 72 knots. The reported stall speed was about 38 knots (44 mph), and its reported best glide speed was about 52 knots (60 mph). The airplane was faster than the recommended glide speed throughout the final approach.