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June 12, 2020 · Bellanca 7KCAB · N36339

Renton, WA

Overview

Report Status
Final with probable cause
Event Type
Accident
Date
June 12, 2020
Injury Outcomes
2 injuries (2 minor injuries)
Location
Renton, WA
Aircraft
Bellanca 7KCAB (1973)
Tail Number
N36339
Operator
Boeing Employees Flying Assoc
Injuries
Minor
Aircraft Damage
Substantial
NTSB Number
WPR20LA180

The airplane had recently undergone an annual inspection, and the accident flight was the first flight since being out of maintenance. After making a normal departure and touch-and-go landing, the pilot receiving instruction applied full power. As the airplane reached an altitude of about 400 feet above ground level (agl), the engine abruptly stopped producing (total) power. The airplane could not maintain level altitude and during the subsequent off-airport landing, the airplane was substantially damaged when it collided with a tree. Postaccident examination revealed that the air induction box contained a piece of bunched up paper that likely restricted the inlet cavity. As part of the annual inspection, a repair person completed a small fiberglass patch and painting on the lower cowling. He could not recall the specific repair on the airplane but said he often placed paper in the induction to prevent debris from entering the engine. After the maintenance, the airplane sat for a day with the lower cowling not fastened but maintenance personnel did not recognize the blockage. They also did not find the paper during the post-maintenance inspections and returned the airplane into service with an unsafe condition.

NTSB Probable Cause

Maintenance personnel’s inadequate post-maintenance inspections that resulted in the total loss of engine power due to a blockage in the air intake.

Full Narrative

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.

Flight

Event TypeAccident
Event Time10:00 PDT
Nearest AirportRenton Municipal Airport (0nm)
Runway16
Runway Length5382 ft
Runway Width200 ft
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo

Aircraft

AircraftBellanca 7KCAB
Tail NumberN36339
Aircraft CategoryAir
DamageSubstantial
OperatorBoeing Employees Flying Assoc
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsLycoming · IO-320-E2A · Reciprocating · 150
Seats2

People & Injuries

Injury Summary2 injuries (2 minor injuries)
Fatal0
Serious0
Minor2
Uninjured0
Total2
Crew 1Age 89 · Basc · Minor
Crew 2Age 59 · Basc · Minor

Conditions

ConditionsVMC
LightDaylight
Wind180° @ 8 kt
Visibility10 sm
CeilingOvercast 3900 ft
Temperature / Dew Point59 / 48
Altimeter29.98 inHg
Observation Time14:53
Weather SourceWFAC

Appendix: Source Data