De Havilland DHC-6 N181CS

Summary

On 6 September 2015 at about 19:40 local time, a De Havilland DHC-6 registered N181CS, operated by Rampart Aviation, was involved in an accident near Louisburg, North Carolina, United States. 3 people were on board and one was seriously injured, one had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

6 September 2015 at 19:40

Classification

Accident

Location

Louisburg, North Carolina, United States

Nearest airport

North Raleigh (00NC)

Coordinates

36.0847, -78.3719

Aircraft

De Havilland DHC-6

Registration

N181CS

Category

Airplane

Year built

1968

Engines

2

Operator

Rampart Aviation

Operating rule

Part 91: General Aviation

Purpose of flight

Aerial Observation

Phase of flight

Not recorded

Route

Washington → Louisburg

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ERA15LA343

1 person was seriously injured.

The propeller’s movement to the beta position during landing for reasons that could not be determined during postaccident examination and testing, which resulted in an attempted go-around and subsequent loss of airplane control.

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

Read the full NTSB narrative

The airline transport pilot was conducting a cross-country aerial observation flight in the multiengine airplane. The pilot reported that the airplane was on the final leg of the traffic pattern when he reduced the power levers for landing and noticed that the right engine sounded like the propeller was moving toward the beta position. The pilot increased the engine power, and the sound stopped. As the airplane got closer to the runway, he decreased the engine power, and the sound returned. In addition, the airplane began to yaw right. The pilot applied left aileron and rudder inputs to remain above the runway centerline without success. While over the runway, the pilot reduced the engine power to idle, and the airplane continued to yaw right. The pilot applied full power in an attempt to perform a go-around; however, the airplane yawed about 30 degrees off the runway centerline, touched down in the grass, and impacted trees before coming to rest. The right wing, right engine, and right propeller assembly were impact-separated. The right engine propeller came to rest about 50 ft forward of the main wreckage, and it was found in the feathered position. A review of maintenance records revealed that the right propeller had been overhauled and reinstalled on the airplane 2 days before the accident and had operated 9 hours since that time. Subsequent testing of the right propeller governor revealed that it functioned without anomaly; however, the speed settings were improperly configured. Further, the testing revealed that the beta valve travel from the neutral position was out of tolerance. Although this could have let oil pressure port to one side of the spool or the other and, thus, changed the propeller blade angle, it could not be determined whether this occurred during the accident landing. Impact damage precluded examination of the right propeller governor control linkage; therefore, it could not be determined if it was inadequately installed or rigged, which could have resulted in the propeller moving into the beta position. The investigation could not determine why the right propeller moved toward the beta position as engine power was reduced, as reported the pilot.

Quoted verbatim from the NTSB record.