Sunday, April 22, 2018

Enstrom TH-180, N180TH, registered to and operated by Enstrom Helicopter Corporation: Accident occurred February 12, 2016 near Menominee-Marinette Twin County Airport (KMNM), Upper Peninsula, Michigan


The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entities:
Federal Aviation Administration / Flight Standards District Office; Grand Rapids, Michigan
Enstrom Helicopter Corporation; Menominee, Michigan
Lycoming Engines; Williamsport, Pennsylvania

Aviation Accident Factual Report - National Transportation Safety Board:https://app.ntsb.gov/pdf

Investigation Docket - National Transportation Safety Board:  https://dms.ntsb.gov/pubdms

http://registry.faa.gov/N180TH

Aviation Accident Factual Report - National Transportation Safety Board

Location: Menominee, MI
Accident Number: CEN16LA105
Date & Time: 02/12/2016, 1123 CST
Registration: N180TH
Aircraft: ENSTROM TH-180
Aircraft Damage: Substantial
Defining Event: Loss of engine power (partial)
Injuries: 1 None
Flight Conducted Under: Part 91: General Aviation - Flight Test 

On February 12, 2016, about 1123 central standard time, an Enstrom TH-180 helicopter, N180TH, was substantially damaged after it impacted obstructions and terrain during an off-airport emergency landing near the Menominee-Marinette Twin County Airport (MNM), Menominee, Michigan. The pilot was not injured. The helicopter was registered to and operated by Enstrom Helicopter Corporation, as a 14 Code of Federal Regulations Part 91 local test flight. Visual meteorological conditions (VMC) prevailed and a flight plan had not been filed. The helicopter had departed MNM, about 1057.

The purpose of the test flight was to ensure the data acquisition system was operating properly. The pilot departed to the north, but because of snow squalls moving into the area, decided to return to the airport. The pilot turned off the data acquisition computer and because of the westerly wind, set up for a right base to runway 32. On final approach, he felt a "jolt in the airframe"; the helicopter yawed left and began to descend. The pilot added throttle, which increased engine rpm but had no effect on the rotor rpm. The low rotor rpm horn sounded, and the pilot entered an autorotation to a city street in a residential neighborhood. During touchdown the main rotor blades struck an electric utility pole as the helicopter slid about 300 feet down the street and came to rest upright. The impacts resulted in the collapse of the skid landing gear and substantial damage to the tail cone, the pylon center section, and the lower section of the cockpit structure. Adequate fuel was found onboard, but there was no fuel spill, and no postimpact fire.

A postaccident examination of the helicopter revealed the 8 mounting bolts for the engine torque meter had sheared separating the engine from the main belt drive system. The torque meter was special test equipment installed between the engine prop flange and a modified lower drive pulley. It was installed to gather engine data during the flight tests. No other preaccident anomalies were found.

An onboard GoPro Hero point-of-view digital camera was center-mounted in the rear of the cockpit and positioned such to provide an over-the-shoulder view of the helicopter flight controls and instrument panel. The micro secure digital (SD) card was removed from the camera and sent to the National Transportation Safety Board Recorders Laboratory for read out.

The micro SD card contained several still image files that appeared to be captured in a time-lapse photo mode. Metadata showed the still images were captured every 10 seconds.

For additional details and information, see the NTSB Onboard Image Recorder Specialist's Factual Report.

At 1115 the automated surface observation system at MNM, recorded wind from 330 degrees at 13 knots with gusts to 24 knots, visibility 10 miles, broken clouds at 4,300 feet, temperature minus 10 degrees Celsius (C), dew point minus 19 degrees C, with an altimeter setting of 30.06 inches of mercury. 



Pilot Information

Certificate: Commercial
Age: 27, Male
Airplane Rating(s): None
Seat Occupied: Left
Other Aircraft Rating(s): Helicopter
Restraint Used: 4-point
Instrument Rating(s): Helicopter
Second Pilot Present: No
Instructor Rating(s): Instrument Helicopter
Toxicology Performed: No
Medical Certification: Class 2 Without Waivers/Limitations
Last FAA Medical Exam: 12/09/2015
Occupational Pilot: Yes
Last Flight Review or Equivalent: 10/23/2014
Flight Time:   (Estimated) 438 hours (Total, all aircraft), 33 hours (Total, this make and model), 240 hours (Pilot In Command, all aircraft), 45 hours (Last 90 days, all aircraft), 23 hours (Last 30 days, all aircraft), 2 hours (Last 24 hours, all aircraft) 

Aircraft and Owner/Operator Information

Aircraft Manufacturer: ENSTROM
Registration: N180TH
Model/Series: TH-180
Aircraft Category: Helicopter
Year of Manufacture: 2015
Amateur Built: No
Airworthiness Certificate: Experimental
Serial Number: 10001
Landing Gear Type: Skid
Seats: 2
Date/Type of Last Inspection:
Certified Max Gross Wt.: 2250 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time:
Engine Manufacturer: Lycoming
ELT:
Engine Model/Series: HIO-390-X
Registered Owner: On file
Rated Power: 210 hp
Operator: On file
Operating Certificate(s) Held: None 

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KMNM, 625 ft msl
Observation Time: 1115 CDT
Distance from Accident Site: 0 Nautical Miles
Direction from Accident Site: 309°
Lowest Cloud Condition:  / 4300 ft agl
Temperature/Dew Point: -10°C / -19°C
Lowest Ceiling: Broken / 4300 ft agl
Visibility: 10 Miles
Wind Speed/Gusts, Direction: 13 knots/ 24 knots, 330°
Visibility (RVR):
Altimeter Setting: 30.06 inches Hg
Visibility (RVV):
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Menominee, MI (MNM)
Type of Flight Plan Filed: None
Destination: Menominee, MI (MNM)
Type of Clearance: None
Departure Time: 1057 CDT
Type of Airspace: Class G

Airport Information

Airport: MENOMINEE-MARINETTE TWIN COUNTY (MNM)
Runway Surface Type: Asphalt
Airport Elevation: 624 ft
Runway Surface Condition: Unknown
Runway Used: 32
IFR Approach: None
Runway Length/Width: 5100 ft / 100 ft
VFR Approach/Landing:  Forced Landing; Full Stop; Traffic Pattern

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 None
Latitude, Longitude: 45.112500, -87.625000 (est)



NTSB Identification: CEN16LA105 
14 CFR Part 91: General Aviation
Accident occurred Friday, February 12, 2016 in Menominee, MI
Aircraft: ENSTROM TH-180, registration: N180TH
Injuries: 1 Uninjured.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

On February 12, 2016, about 1123 central standard time, an Enstrom TH-180 helicopter, N180TH, was substantially damaged after it impacted obstructions and terrain during an off-airport emergency landing near Menominee-Marinette Twin County Airport (MNM), Menominee, Michigan. The pilot was not injured. The helicopter was registered to and operated by Enstrom Helicopter Corporation, as a 14 Code of Federal Regulations Part 91 test flight. Visual meteorological conditions (VMC) prevailed and a flight plan had not been filed. The helicopter had departed MNM, about 1057 for a local flight.

The helicopter was on a right base to land on runway 32 when the pilot felt a "jolt" in the airframe and noticed a sudden reduction in rotor rpm, although the engine continued to run. The pilot entered an autorotation and touched down on a city street in a residential neighborhood. During touchdown the main rotor blades struck an electric utility pole as the helicopter slid about 300 feet down the street and came to rest upright. The impacts resulted in the collapse of the skid landing gear and substantial damage to the tail cone, the pylon center section, and the lower section of the cockpit structure. Adequate fuel was found onboard, but there was no fuel spill, and no postimpact fire.

At 1115 the automated surface observation system at MNM, reported wind from 330 degrees at 13 knots with gusts to 24 knots, visibility 10 miles, broken clouds at 4,300 feet, temperature minus 10 degrees Celsius (C), dew point minus 19 degrees C, with an altimeter setting of 30.06 inches of mercury.

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