Individually Owned: 150,657
Corporate Owned: 137,281
N/A Airport
Aircraft Accident/Incident Report
Tomah, Wisconsin 54660
Thursday, August 7, 2014 9:46 CDT
NTSB Narrative Summary Released at Completion of Accident
On August 7, 2014, about 0946 central daylight time, an Enstrom F-28F helicopter, N213BL, was substantially damaged when the pilot executed a precautionary landing in a cornfield after experiencing engine difficulties near Tomah, Wisconsin. The pilot was seriously injured. The helicopter was registered to and operated by Paul Peterson Aviation LLC under the provisions of 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The local flight originated from the loading site about one-half mile from the accident site.
The pilot's departure from the loading site on the third application flight of the morning proceeded without incident. However, about one-half mile from the planned application field, the pilot reportedly felt a vibration in the cyclic control and experienced an "irregular" running engine. He immediately elected to execute a precautionary landing to a corn field; the corn crop was approximately 10 feet tall at the time. During the landing, the landing skids collapsed and the tailboom was severed by a main rotor blade. A portion of the tail rotor drive shaft was separated from the airframe. Separation of the drive shaft was consistent with a main rotor strike. The tail rotor transmission separated into two sections; the appearance of the fracture surface was consistent with an overstress failure.
The postaccident examination did not reveal any preimpact anomalies with respect to the flight control system and rotor drive system. Examination of the engine revealed that the no. 4 cylinder did not exhibit compression during crankshaft rotation. Further examination of the No. 4 cylinder determined that the intake valve was not seating properly; a gap of approximately 0.015 inch existed when the valve should have been fully seated. Linear scoring were observed on the valve stem. Debris consistent with valve guide material was also recovered on removal of the valve. No other anomalies with respect to the engine were observed.
The accident helicopter was purchased by the operator on June 4, 2014. The aircraft was issued a restricted category, special airworthiness certificate for agriculture operations on July 25, 2014. The operator reported a total airframe time of 2,385.1 hours at the time of the accident. The most recent annual inspection was completed in December 2013 at 2,327.4 hours.
The helicopter was powered by a 225-horsepower Lycoming HIO-360-F1AD fuel-injected, reciprocating engine. Maintenance records indicated that the engine was overhauled in March 2006. At the time of the accident, the engine had accumulated about 831.2 hours since overhaul, with about 57.7 hours of that time since the annual inspection. The most recent engine maintenance entry was dated August 4, 2014, and consisted of replacement of the spark plugs. The helicopter maintenance records did not contain a record of any unresolved maintenance issues.
NTSB Probable Cause Narrative
Not Yet Reported
Event Information
| Type of Event | Accident |
| Event Date | 8/7/2014 |
| Event Day of the Week | Thursday |
| Time of Event | 946 |
| Event Time Zone | Central Daylight Time |
| Event City | Tomah |
| Event State | WISCONSIN |
| Event Country | -- |
| Zipcode of the event site | 54660 |
| Event Date Year | 2014 |
| Event Date Month | 8 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 435743N |
| Event Location Longitude | 0903448E |
| Event Location Airport | N/A |
| Event Location Nearest Airport ID | -- |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | -- |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1035 Central Daylight Time |
| Direction of event from weather observation facility (degrees) | 270 |
| Weather Observation Facility ID | CMY |
| Elevation of weather observation facility | 838 |
| Distance of event from weather observation facility (units?) | 7 |
| Time Zone of the weather observation | CDT |
| 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) | 25 |
| Dew Point at event time (in degress fahrenheit) | 12 |
| Wind Direction (degrees magnetic) | 110 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 7 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.12 |
| 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 |
| NTSB Docket Number (internal use) | -- |
| NTSB Notification Source | FAA -- MKE FSDO |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Nov 10 2014 11:30AM |
| User who most recently changed record | sort |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N213BL |
| NTSB Number | CEN14LA412 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 137: Agricultural |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | -- |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | ENSTROM |
| Aircraft Model | F 28F |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 803 |
| 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 | 2 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | Dec 2 2013 12:00AM |
| Airframe hours since last inspection | -- |
| Airframe Hours | 2385.1 |
| ELT Installed | Yes |
| ELT Activated | Yes |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Paul Peterson Aviation LLC |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | Lanesboro |
| Aircraft Owner State | MN |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 55949 |
| Operator is an individual? | No |
| Operator Name | Paul Peterson Aviation LLC |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | -- |
| Operator City | Lanesboro |
| Operator State | MN |
| Operator Country | USA |
| Operator Zip code | 55949 |
| Operator Code | -- |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | -- |
| Certified for Part 133 or 137 Operation | -- |
| Operator Certificate Number | 3P2G833N |
| 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 Application |
| Second Pilot on Board | No |
| Departure Point Same as Event | No |
| Departure Airport Code | PVT |
| Departure City | Tomah |
| Departure State | WI |
| Departure Country | USA |
| Departure Time | 930 |
| Departure Time Zone | CDT |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | PVT |
| Destination City | Tomah |
| Destination State | WI |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Nov 10 2014 3:30PM |
| User who most recently changed record | sort |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | N/A |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |