Enstrom F-28F N918DK

Summary

On 27 March 2013 at about 18:00 local time, a Enstrom F-28F registered N918DK, operated by Wybenga Steve, was involved in an accident near Twin Falls, Idaho, United States. One person was 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

27 March 2013 at 18:00

Classification

Accident

Location

Twin Falls, Idaho, United States

Nearest airport

Joslin Field-Magic Valley Rgnl (TWF)

Coordinates

42.4758, -114.4861

Aircraft

Enstrom F-28F

Registration

N918DK

Category

Helicopter

Engines

1

Operator

Wybenga Steve

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Twin Falls → Twin Falls

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR13LA167

Nobody was injured.

A total loss of engine power for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation. 

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

Read the full NTSB narrative

The student pilot reported that, during the helicopter's fourth landing, the engine started to sputter and lose rpm. He lowered the collective and added power, and the engine rpm increased. When he raised the collective, the engine lost power again. As he turned the helicopter to land it on the runway, the engine lost total power, and he performed an autorotation to a field. During the landing, one of the helicopter's skids got stuck in soft dirt, and the helicopter subsequently rolled onto its left side. Postaccident examination of the airframe and engine revealed no flight control or fuel system continuity anomalies. The single-drive dual magneto, ignition harness, and spark plugs were removed for further examination. The examination revealed that the left distributor gear was internally timed to the counter clockwise (CCW) marking and that the right distributor gear was internally timed to the clockwise (CW) marking. However, both distributor gears should have been timed relative to the CCW markings in accordance with the magneto manufacturer's Service Support Manual. When one of the distributor gears is timed to the CW markings instead of the CCW markings, a four-teeth difference in timing between the gears can occur. According to the magneto service representative and the magneto manufacturer's magneto specialist, the four-teeth timing difference would only have resulted in faster wear on the magneto's internal components. Given that the magneto was recently overhauled, it is likely that the magneto was operating as designed at the time of the engine loss. The reason for the loss of engine power could not be determined.

Quoted verbatim from the NTSB record.