Back to Search

NTSB investigation record

CEN15FA315

Completed

Sanford Zenith ch601Xl· N9601

Date
July 25, 2015
Location
Bristol, WI
Conditions
VMC
Record
Published September 25, 2020

Primary finding

Probable cause

The pilot’s failure to maintain airspeed and airplane control following a loss of engine power during cruise flight. Contributing to the accident was the installation of ignition system coils that were not engine-manufacturer replacement parts, which subsequently failed and resulted in the loss of engine power.

Investigator assessment

Analysis narrative

The pilot was flying his experimental, amateur-built airplane on a cross-country flight. GPS and radar data showed that, about an hour into the flight, the airplane turned left and then turned right. About 1 minute later, the airplane's groundspeed slowed to below its stall speed, and the airplane then entered a steep descent. Witnesses reported seeing the airplane "corkscrew" downward, and one witness reported that the propeller was "not spinning." Flight control continuity was confirmed, and witness marks on the propeller blades were consistent with the propeller not rotating at impact. A pilot who shared a hangar with the accident pilot reported that the accident pilot replaced the airplane's ignition system coils the day before the flight. Postaccident examination of the engine revealed that the coils were not engine-manufacturer replacement parts. During a postaccident test run, the engine would not start. During subsequent troubleshooting, the right distributor center coil tower socket was found separated; further examination revealed that it failed due to overload. The right ignition coil was then connected to the left distributor cap, and the engine operated normally during the subsequent test run. The broken right distributor cap was then replaced with a new cap, the right ignition coil was connected to the new cap, and the engine again operated normally during a subsequent test run. The left ignition coil did not produce any sparks during the test runs. No other anomalies were observed during the engine runs that would have prevented normal operation. The airplane likely experienced a loss of engine power due to the ignition issues, and the pilot failed to maintain adequate airspeed, which resulted in a subsequent stall and loss of airplane control.

Source record

Factual narrative

The Kenosha County Medical Examiner's Office arranged for an autopsy to be performed on the pilot along with taking toxicological samples. The pilot's autopsy indicated that his cause of death was due to multiple blunt force injuries. The FAA Civil Aerospace Medical Institute prepared a Final Forensic Toxicology Accident Report on the samples taken during the pilot's autopsy. The report, in part, indicated: 182 (mg/dl) Glucose detected in Vitreous 6.6 (%) Hemoglobin A1C detected in Blood At 1135, the recorded weather at the Kenosha Regional Airport, near Kenosha, Wisconsin, was: wind 310 degrees at 9 knots; visibility 10 statute miles; sky condition scattered clouds at 2,000 feet, broken clouds at 4,000 feet; temperature 28 degrees C; dew point 23 degrees C; altimeter 29.94 inches. The 69-year-old pilot held a FAA private pilot certificate with an airplane single-engine land rating. He also held a second-class medical certificate that was issued on August 27, 1979, with a limitation that he must wear corrective lenses. The pilot reported on the application for that medical certificate that he had accumulated 250 hours of total flight time and accumulated no flight time in six months prior to that application. According to a witness, the pilot received 10 hours of dual time in the airplane with a flight instructor to comply with an insurance requirement. The passenger did not hold a pilot certificate but had been reported to have taken flight training. The airplane came to rest upright about one-quarter mile and 110 degrees from the intersection of 60th Street and 172nd Avenue in Bristol. The airplane's resting heading was about 310 degrees. One propeller blade remained intact and attached to the hub and the other blade was broken into three sections. The inboard section remained attached to the hub. The outboard blade section was found embedded in terrain about eight feet north of the hub. The embedded blade section exhibited abrasions perpendicular to the blade's chord. The intact blade exhibited no abrasions. The empennage remained attached to the fuselage. The top of the rudder was displaced rearward and it exhibited a wrinkle deformation below that displacement. Both wings exhibited chrodwise wrinkle deformations inboard of their approximate midspans. The forward portion of the fuselage was deformed where it met the canopy. The sides of the fuselage above each wing were deformed between the end of the canopy and the firewall. The right wing fuel tank did not contain any fuel and disassembly of its leading edge revealed the right fuel tank was breached. The left fuel tank contained a blue colored liquid that had a smell consistent with Avgas. The fuel tank selector valve was on the left tank. The gascolator contained a liquid consistent with Avgas. The carburetor bowl was removed and it contained a blue colored liquid that had a smell consistent with Avgas. Flight control continuity was established from the cockpit flight controls to their respective flight control surfaces. Both flaps moved in the same direction when each was manipulated by hand. The flap's actuator control rod separated from its flap linear actuator. No preimpact anomalies were detected that would have prevented normal flight operations. The airplane, a Sanford Zenith CH 601XL, was an all-metal, two-seat side-by-side, fixed tricycle landing gear airplane. According to FAA airworthiness documents, the accident airplane was produced from a kit by a builder and it received an airworthiness certificate in the Experimental, Amateur Built category on July 2, 2008. The airplane was powered by a 120-horsepower, Jabiru 3300A engine with serial number 33A 1380, which drove a Sensenich composite, ground adjustable, two-bladed propeller. According to the kit manufacturer's website, the airplane's stall speed with no flaps extended was 51 mph (about 44.32 knots). The airplane was equipped with a Dynon FlightDEK-D180 seven-inch wide screen display unit. The unit's primary functions include attitude, airspeed, altitude, vertical speed, gyro-stabilized magnetic compass, slip/skid ball, turn rate, clock, timers, g-meter, and horizontal situation indicator. This instrument features ADAHRS (Air Data, Attitude and Heading Reference System), which integrates over a dozen solid-state sensors. The unit can continuously monitor up to 27 available sensor inputs that cover the engine, fuel and other miscellaneous systems and annunciate any abnormality immediately upon detection. The Dynon's internal memory is capable of logging data depending on the firmware version installed in the unit. The data logging must be configured by the operator to enable logging and set the data log interval. The unit can also be configured to start logging data automatically at boot-up. The data logging interval can be set to store at 1, 3, 5, 10, 30, or 60-second intervals. The internal memory can store at least 30 minutes of cumulative data at a 1-second recording interval or at least 30 hours at a 60-second data recording interval. When the recording limit in the internal memory is reached, the oldest record is dropped and a new record is added. The airplane was also equipped with a Garmin GPSMAP 396 unit. The unit is a battery-powered, portable 12-channel GPS receiver with a 3.8-inch 256-color TFT LCD display screen that can show a color moving-map and it has terrain-alerting features along with satellite datalink graphical weather. The unit includes a built-in Jeppesen database. The unit stores date, route-of-flight, and flight-time information. A flight record is triggered when groundspeed exceeds 30 knots and altitude exceeds 500 feet, and ends when groundspeed drops below 30 knots for 10 minutes or more. A detailed track log including latitude, longitude, date, time, and GPS altitude information is stored within the unit whenever the receiver has a lock on the GPS navigation signal. A witness, who shared a hangar with the accident pilot, purchased the accident airplane from an individual in Texas. At purchase, the airplane had damage to its propeller, leading edges, and horizontal stabilizer. He indicated that the airplane "got away" from the individual in Texas when he exited the airplane while running to close the hangar door. The airplane upgrade modification had been completed before being damaged and the airplane did not have an engine stoppage during the damaging event. The accident pilot and the witness did all the repairs to the airplane and had an airframe and powerplant mechanic look over the repairs as they progressed. The accident pilot registered the airplane. The mechanic did the annual inspection, and signed off the logbook. According to this witness, the airplane had known issues. In the year before the accident, on a flight from Louisville, Kentucky, to Phoenix, AZ, 10 minutes into the flight the accident pilot felt a vibration. He returned to the airport, removed the cowling, and troubleshot for the vibration issue. However, he could not find the cause. He subsequently did a run up, a few high-speed taxi tests, and determined it the airplane was okay to fly. He departed again and about an hour into this flight, he noticed the vibration return, so he landed at an airport. The pilot and witness inspected the airplane and found the engine to have a weak spark. The accident pilot bought replacement coils at a "mower shop" as he was told they were the same. They installed the newly purchased coils, the airplane subsequently ran with no issues, and the accident pilot returned without further incident. The accident pilot flew the airplane for several hours without any further coil issues. The witness indicated the condition inspection was completed on June 11, 2015. The witness stated that two problems were found that needed to be corrected. The nose wheel bushings were too short and needed to be replaced along with the propeller's locking washers. Both items were ordered and rep

Continue research

Find similar accidents

Continue with the strongest shared characteristics.