Joslin Field-Magic Valley Rgnl Airport
Aircraft Accident/Incident Report

Twin Falls, Idaho 83301
Wednesday, March 27, 2013 12:00 MDT

NTSB Narrative Summary Released at Completion of Accident

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.

NTSB Probable Cause Narrative

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. 

Event Information

Type of Event Accident
Event Date 3/27/2013
Event Day of the Week Wednesday
Time of Event 1200
Event Time Zone Mountain Daylight Time
Event City Twin Falls
Event State IDAHO
Event Country --
Zipcode of the event site 83301
Event Date Year 2013
Event Date Month 3
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 422833N
Event Location Longitude 1142910W
Event Location Airport Joslin Field-Magic Valley Rgnl
Event Location Nearest Airport ID TWF
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles 1
Degrees magnetic from airport 300
Airport Elevation 4154
Weather Briefing Completeness --
Investigator's weather source Weather Observation Facility
Time of the weather observation 1153 Mountain Daylight Time
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID TWF
Elevation of weather observation facility 4154
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation MDT
Lighting Conditions Day
Lowest Ceiling Height --
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 12
Dew Point at event time (in degress fahrenheit) 2
Wind Direction (degrees magnetic) 60
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 6
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30.01
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report KTWF 271753Z 06006KT 10SM CLR 12/02 A3001 RMK AO2
Event Highest Injury None
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor --
Injury Total None 1
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 32791
NTSB Notification Source FAA ROC
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information --
Date of most recent change to record Jun 10 2014 12:23PM
User who most recently changed record lins-i
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N918DK
NTSB Number WPR13LA167
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? No
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name ENSTROM
Aircraft Model F-28F
Aircraft Series Identifier --
Aircraft Serial Number 755
Certified Max Gross Weight 2600
Aircraft Category Helicopter
Aircraft Registration Class --
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 3
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Feb 18 2013 12:00AM
Airframe hours since last inspection 8
Airframe Hours 5497
ELT Installed No
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name WYBENGA STEVE
Aircraft Owner Street Address --
Aircraft Owner City TWIN FALLS
Aircraft Owner State ID
Aircraft Owner Country USA
Aircraft Owner Zipcode 83301
Operator is an individual? No
Operator Name WYBENGA STEVE
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address --
Operator City TWIN FALLS
Operator State ID
Operator Country USA
Operator Zip code 83301
Operator Code --
Owner has at least one certificate None
Other Operator of large aircraft? --
Certified for Part 133 or 137 Operation --
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Instructional
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code TWF
Departure City Twin Falls
Departure State ID
Departure Country USA
Departure Time 1050
Departure Time Zone MDT
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code TWF
Destination City Twin Falls
Destination State ID
Destination Country USA
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jun 19 2014 1:32PM
User who most recently changed record stam
Since inspection or accident Last Inspection
Event Location Runway Number and Location N/A
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --