Enstrom TH-180 N180TH

Summary

On 12 February 2016 at about 17:23 local time, a Enstrom TH-180 registered N180TH was involved in an accident near Menominee, Michigan, 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

12 February 2016 at 17:23

Classification

Accident

Location

Menominee, Michigan, United States

Nearest airport

Menominee-Marinette Twin Count (MNM)

Coordinates

45.1125, -87.6250

Aircraft

Enstrom TH-180

Registration

N180TH

Category

Helicopter

Year built

2015

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Flight Test

Phase of flight

Not recorded

Route

Menominee → Menominee

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN16LA105

Nobody was injured.

The failure of the torque meter mounting bolts, which resulted in a loss of engine power to the main drive belt and rotors.

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

Read the full NTSB narrative

The commercial pilot of the helicopter departed to conduct a flight test of an onboard data acquisition system. About 18 minutes later, the pilot decided to return to the airport because of weather moving into the area. On final approach, the pilot felt a "jolt in the airframe," and the helicopter yawed left and began to descend. The pilot added engine power, but the main rotor rpm continued to decay until the low rotor rpm horn sounded. The pilot entered an autorotation to a city street in a residential neighborhood. During the landing, the main rotor struck an electric utility pole and the helicopter slid 300 ft before coming to a stop. A postaccident examination of the helicopter revealed that the eight mounting bolts for the engine torque meter had sheared, separating the engine from the main belt drive system. The torque meter was test equipment installed between the engine prop flange and a modified lower drive pulley for the purpose of gathering engine data during the flight tests. No other preaccident anomalies were found.

Quoted verbatim from the NTSB record.