According to the pilot, who was also the owner of the experimental, amateur-built Escapade, shortly after departure from a private airport near Brasstown, North Carolina, the engine developed vibrations and an “unusual sound.”
He attempted to return to the airport, which was about 8 nautical miles away. Although the engine was developing power, it was losing coolant and the coolant and oil temperatures were rising to excessive levels.
In lieu of flying an airport traffic pattern, which would take additional time, he elected to land as soon as possible on an unmowed portion of the airport. The nose gear collapsed during the landing, which resulted in damage to the fuselage and windscreen.
The wreckage was subsequently recovered and examined by an FAA inspector, who noted substantial damage to the airframe.
The accident, which was reported about a month after it occurred, and the subsequent follow-up examination by the FAA, took additional time before the damage was confirmed. During that time the pilot, who was also an airframe and powerplant mechanic, conducted his own examination.
The pilot stated that during his examination of the experimental Viking 110 engine (Honda Derivative), it was revealed that the drive flange, also known as the engine to gearbox coupling or “spider,” located on the rear of the gearbox, had failed. The resulting failure threw fragments into the radiator, damaging it and resulting in coolant loss.
The pilot removed the flange, which was missing one of the three drive ears. One of the ears was fractured just outside of the main splined driveshaft hole.
The flange was installed on the engine about 134 flight hours before the accident by the previous owner of the airplane. A review of the engine manufacturer’s operational manuals and service bulletins revealed that this unit was in compliance with the service bulletin specific to the welding of the pins and installation.
Probable Cause: The failure of the engine gearbox drive flange, which resulted in a nose gear collapse during the subsequent precautionary landing in tall grass.
To download the final report. Click here. This will trigger a PDF download to your device.
This May 2022 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
