Messerschmitt-Bolkow-Blohm BK 117 B-2 N1174U

Summary

On 5 March 2018 at about 05:24 local time, a Messerschmitt-Bolkow-Blohm BK 117 B-2 registered N1174U, operated by Air Methods Corporation, was involved in an accident near Sheboygan, Wisconsin, United States. 3 people were 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

5 March 2018 at 05:24

Classification

Accident

Location

Sheboygan, Wisconsin, United States

Nearest airport

Sheboygan County Memorial (SBM)

Coordinates

43.7644, -87.8514

Aircraft

Messerschmitt-Bolkow-Blohm BK 117 B-2

Registration

N1174U

Category

Helicopter

Year built

1988

Engines

2

Operator

Air Methods Corporation

Operating rule

Part 135: Air Taxi & Commuter

Phase of flight

Not recorded

Route

Fond du Lac → Sheboygan

Aircraft damage

Substantial

Weather

VMC

Light

Night

NTSB number

CEN18LA115

Nobody was injured.

The restricted cyclic control movement for reasons that could not be determined because postaccident examination and testing of the cyclic control system did not reveal any evidence of mechanical malfunctions or failures that would have precluded normal operation.

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

Read the full NTSB narrative

Before departure on the air ambulance flight, standard flight control and hydraulic transfer checks were performed with no anomalies noted with the flight controls. The helicopter’s hover, departure, and cruise were normal. During his approach to the hospital, the pilot started a slow descent using the collective and performed the before landing checks; all systems were normal. However, when attempting to decelerate from cruise speed, the pilot noticed restricted cyclic control movement, about 1 inch in any direction, with normal collective and yaw control movement. He then chose to abort the descent and execute a precautionary landing at a nearby airport. During the short flight to the airport, the pilot cycled the hydraulic test switch twice with no change noted to his flight controls. During the approach to land, the pilot held the cyclic trim switch aft in an attempt to gain additional aft cyclic authority. With continuous cyclic pressure against the aft stop, the pilot was able to slow the helicopter to 80 knots on final approach. The helicopter touched down near the runway centerline, skidded about 500 ft, exited the runway surface, and came to rest upright. The helicopter sustained substantial damage to the main rotor blades and fuselage structure. Postaccident examination of the helicopter’s flight control system, including the trim system, did not reveal any evidence of malfunctions or failures that would have precluded normal operations. The cyclic trim was found in the full forward and left position. The flight control dual hydraulic pack was functionally tested on the helicopter and at a repair facility with no anomalies noted. Thus, the reason for the restricted cyclic control movement could not be determined.

Quoted verbatim from the NTSB record.