Construcciones Aeronauticas Sa CASA-212 N437RA

Summary

On 2 November 2008 at about 03:02 local time, a Construcciones Aeronauticas Sa CASA-212 registered N437RA, operated by Arctic Transportation Services, Inc., was involved in an accident near Toksook Bay, Alaska, United States. 2 people were on board and 2 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

2 November 2008 at 03:02

Classification

Accident

Location

Toksook Bay, Alaska, United States

Nearest airport

Toksook Bay AIrport (OOK)

Coordinates

60.5414, -165.0872

Aircraft

Construcciones Aeronauticas Sa CASA-212

Registration

N437RA

Category

Airplane

Engines

2

Operator

Arctic Transportation Services, Inc.

Operating rule

Part 135: Air Taxi & Commuter

Phase of flight

Not recorded

Route

Bethel → Toksook Bay

Aircraft damage

Substantial

Weather

VMC

Light

Dusk

NTSB number

ANC09LA009

2 people had minor injuries.

The flight crew’s inability to adjust/increase power to the right engine during the landing approach due to an in-flight disconnect of the engine power control linkage, resulting in a loss of control of the airplane. Contributing to the accident was the flight crew’s delayed response in feathering the right engine propeller.

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

Read the full NTSB narrative

According to the captain, as the first officer turned the twin-engine turboprop airplane from base leg to final, she advanced the engine power levers to increase engine power, but the right engine did not respond and the airplane yawed to the right. About 500 feet above the ground, the captain said that he took control and initiated a go-around by adding full engine power. As power was increased, the yaw intensified, and the captain said he was unable to maintain altitude. As he called for the first officer to feather the right engine, the stall warning horn sounded and he had to use both hands to maintain control of the airplane. The airplane continued to descend, struck the tundra-covered terrain, and sustained substantial damage to the fuselage, wings, and empennage. The right engine propeller was not feathered at impact. A postaccident inspection revealed that the linkage connecting the cockpit-mounted engine power lever to the right engine propeller pitch control (PPC) was disconnected, and the bolt connecting the linkage to the PPC was missing. Company management reported that the right engine had been changed 237.2 flight hours before the accident, which required the removal and reinstallation of the PPC linkage. Additionally, the airplane had undergone a scheduled maintenance inspection event following the engine change, 114.3 hours before the accident, requiring a functional test of the torque on the bolt that attaches the linkage. The inspection is part of the operator’s approved airworthiness inspection program. Once the PPC linkage disconnected, the flight crew was unable to control the right engine’s thrust, making it difficult for them to maintain control of the airplane during the approach. Since the bolt that connects the PPC linkage to the splined shaft was not found, it is unknown if the bolt failed or if maintenance personnel failed to properly tighten/torque the bolt at installation.

Quoted verbatim from the NTSB record.