N36339Bellanca 7KCAB · 1973

On June 12, 2020, about 1000 Pacific daylight time, a Bellanca 7KCAB Citabria airplane, N36339, was substantially damaged when it was involved in an accident near Renton, Washington. The certified flight instructor (CFI) and pilot receiving instruction sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight.

The airplane had recently undergone an annual inspection and the accident flight was the first flight since being out of maintenance. The operator, Boeing Employees Flying Association, required that a test flight be performed following annual inspections and the CFI was authorized to perform those flights. The CFI elected to take the pilot receiving instruction for the test flight since she was working on obtaining her tailwheel endorsement. The test flight protocol provided an extended checklist including an elongated preflight and runup.

The CFI added 10 gallons of fuel in each wing tank and the engine start and runup were all normal. With the pilot receiving instruction positioned in the front seat, she performed the initial takeoff from runway 16 and they remained in the traffic pattern with the intention of performing touch-and-go takeoff practice and landings. After making an uneventful three-point landing, the pilot receiving instruction applied full throttle and the airplane accelerated reaching an altitude of about 400 feet above ground level (agl). At that time, the engine abruptly stopped producing (total) power, although the propeller continued to rotate. The CFI opted to land on an access road. During the off-airport landing, the airplane sustained substantial damage to both wings and the fuselage when it collided with a tree before coming to rest in a vacant construction company storage area.

The CFI stated that the airplane was too low for him to look at the instruments or perform troubleshooting steps and from the rear seat he did not have good visual access to the engine gauges. The pilot receiving instruction stated that immediately following the power loss, the CFI asked her what was happening. She confirmed that the throttle was fully forward, the mixture was rich, and the fuel selector valve and boost pump were both in the ON position.

During a postaccident examination, investigators discovered the air induction box contained an approximate two by three feet piece of bunched up paper that was white and had a plastic type coating. The paper appeared to have mostly restricted the inlet cavity (see figure 1).

Figure 1: Picture of Air Induction

The lead mechanic who performed the annual inspection before the accident stated that as part of the annual inspection, the airplane needed a repair concerning a hole near the exhaust on the lower cowling. He hired a local repair person he normally uses to complete the fiberglass work and painting. After the maintenance, the airplane sat for a day with the lower cowling/ air filter off.

After the work was completed and the lower cowling was reinstalled, the mechanic completed a final inspection followed by a post-inspection run-up, with no discrepancies noted.

The were no other anomalies found during the postaccident examination.