Aircraft Accident/Incident Report

Leroy, Minnesota 55951
Monday, August 23, 2004 9:50 CDT

NTSB Narrative Summary Released at Completion of Accident

The helicopter sustained substantial damage when it impacted terrain and rolled over after a loss of engine power during takeoff. The pilot reported that the engine was producing 3,000 rpm's when he brought the helicopter into a hover. He transitioned into forward flight and cleared a fence, and then the engine lost power. He reported that he thought that an exhaust valve was stuck. He attempted to do a run on landing to a field. The helicopter touched down on its left skid two times but the helicopter was not straight. He reported that the third time the helicopter touched down on its left skid, the helicopter was not straight and the rpm's were low. He reported that he ran out of tail rotor authority. The helicopter rolled over on its left side. The engine was inspected and an engine run was conducted. The engine was run at 1,800 to 2,000 rpm, and then at 1,110 to 1,200 rpm; but the engine popped and ran unevenly. A re-inspection of the engine revealed that the 1/8-27 NPT Allen plug to the number four cylinder was missing. Once the hole was plugged, the engine ran smoothly.

NTSB Probable Cause Narrative

The partial loss of engine power due to the missing 1/8-27 NPT Allen plug as a result of other maintenance personnel undertorquing the plug. Additionally, the pilot improperly excecuted a run on landing. A factor was the loss of tail rotor effectiveness.

Event Information

Type of Event Accident
Event Date 8/23/2004
Event Day of the Week Monday
Time of Event 950
Event Time Zone Central Daylight Time
Event City Leroy
Event State MINNESOTA
Event Country --
Zipcode of the event site 55951
Event Date Year 2004
Event Date Month 8
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 435315N
Event Location Longitude 0925035W
Event Location Airport --
Event Location Nearest Airport ID --
Indicates whether the acc/inc occurred off or on an airport --
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness --
Investigator's weather source Unknown
Time of the weather observation
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID --
Elevation of weather observation facility --
Distance of event from weather observation facility (units?) --
Time Zone of the weather observation --
Lighting Conditions Day
Lowest Ceiling Height --
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions --
Sky Condition for Lowest Ceiling --
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) --
Air Temperature at event time (in degrees celsius) --
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) --
Variable Wind Indicator --
Wind Speed (knots) --
Wind Velocity Indicator --
Wind Gust Indicator Unknown
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury Serious
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor --
Injury Total None --
Injury Total Serious 1
Injury Total All 1
Investigating Agency --
NTSB Docket Number (internal use) 16485
NTSB Notification Source FAA
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Oct 28 2004 10:11AM
User who most recently changed record NTSB\MONR
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N9573
NTSB Number CHI04CA237
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 --
Aircraft Manufacturer's Full Name Enstrom
Aircraft Model F-28A
Aircraft Series Identifier --
Aircraft Serial Number 131
Certified Max Gross Weight --
Aircraft Category Helicopter
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft --
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection --
Date of Last Inspection --
Airframe hours since last inspection --
Airframe Hours --
ELT Installed Unknown
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name P & N Corporation
Aircraft Owner Street Address --
Aircraft Owner City --
Aircraft Owner State --
Aircraft Owner Country --
Aircraft Owner Zipcode --
Operator is an individual? No
Operator Name P & N Corporation
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address 1710 Marion Airport Rd.
Operator City Marion
Operator State IA
Operator Country USA
Operator Zip code 52302
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) Aerial Observation
Second Pilot on Board --
Departure Point Same as Event Yes
Departure Airport Code --
Departure City Leroy
Departure State MN
Departure Country USA
Departure Time 948
Departure Time Zone CDT
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code --
Destination City --
Destination State --
Destination Country --
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Sep 13 2004 5:30PM
User who most recently changed record DINC
Since inspection or accident --
Event Location Runway Number and Location --
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --