Cessna 206 N5152U

Summary

On 10 August 2019 at about 01:20 local time, a Cessna 206 registered N5152U, operated by Skinner Leasing LLC, was involved in an accident near Prospect, Oregon, United States. 2 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

10 August 2019 at 01:20

Classification

Accident

Location

Prospect, Oregon, United States

Coordinates

42.6500, -122.3250

Aircraft

Cessna 206

Registration

N5152U

Category

Airplane

Year built

1964

Engines

1

Operator

Skinner Leasing LLC

Operating rule

Part 135: Air Taxi & Commuter

Purpose of flight

Fire Fighting

Phase of flight

Not recorded

Route

Medford → Medford

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR19LA217

Nobody was injured.

The failure of the counterweight retainer pin plate which resulted in a total loss of engine power.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

About 2.8 hours into the fire reconnaissance mission flight, the pilot heard a loud bang followed by violent shaking of the airplane. The pilot believed the airplane was at an altitude of about 1,500-2,000 ft. above the ground. The pilot retarded the propeller control to extend his glide distance while he looked for a place to land. The airplane touched down in a swamp and during the landing, the left wing and fuselage were substantially damaged. A postaccident examination of the engine revealed extensive damage to the no. 1 cylinder, piston, and connecting rod. The no. 1 cylinder valve guide rods broke through the crankcase, and the rear counterweight and counterweight lobe were broken free from the crankshaft. Numerous metal pieces and shavings were noted in the oil pan including: a broken counterweight, crankshaft counterweight attachment, counterweight retainer pin, damaged retainer pin plates, damaged retainer plate spring clips, and engine casing pieces. One of the damaged retainer pin plates displayed a deep groove, the approximate diameter of a counterweight pin. It is likely that the counterweight retaining pin rotated over time on the counterweight retainer pin plate, causing it to wear down and eventually fail. When the plate failed, the counterweight retainer pin moved from its position and impacted the no. 1 piston rod, causing the counterweight lobe to fracture and the engine to lose power.

Quoted verbatim from the NTSB record.