Messerschmitt-Bolkow-Blohm BK 117 B-2 accident near Sheboygan, Wisconsin, March 5, 2018
On March 5, 2018 at about 5:24 am local time, a 1988 Messerschmitt-Bolkow-Blohm BK 117 B-2 (helicopter), registered N1174U, was substantially damaged in an accident during approach near Sheboygan, Wisconsin (Sheboygan County Memorial airport). It was flown under charter and air-taxi rules (Part 135). No one was hurt; 3 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 5, 2018 · about 5:24 am local time · cases in 2018
- Place
- Sheboygan, Wisconsin · Sheboygan County Memorial · cases near this airport · map
- Type
- Accident
- Injuries
- No one was hurt; 3 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Messerschmitt-Bolkow-Blohm BK 117 B-2, built 1988 · all BK 117 B-2s on the register
- Registration
- N1174U · registry record · serial 7146
- Damage
- Substantial damage
- Flight
- Flight · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Sys/Comp malf/fail (non-power) during approach defining event
- Hard landing during landing
- Runway excursion during landing
The NTSB's findings
- cause Not determined › Not determined › (general) › (general) › Unknown/Not determined
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; instrument: helicopter; rotorcraft: helicopter
- Flight time: 5,684 hours in all; 84 in this make and model; 18 in the last 90 days; 8 in the last 30 days; 3,746 as pilot in command
- Last flight review: June 5, 2017
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 8,613 hours
- Last inspection: approved inspection programme, February 15, 2018
- Maximum gross weight: 7,385 lb
- Seats: 7
- Landing gear: fixed
- Engine 1: Honeywell LTS-101 (turboshaft); 7,517 hours total
- Engine 2: Honeywell LTS-101 (turboshaft); 8,965 hours total
- Operator: Air Methods Corporation
The flight
- Departed from: FLD Fond du Lac WI at 4:57 am
- Destination: SBM Sheboygan WI
- Flight plan: none
- Runway 13, 5,002 ft by 75 ft
Weather at the time
- Light: night
- Wind: from 110° at 9 knots, gusting 18
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 36°F (2°C), dew point 25°F (-4°C)
- Altimeter: 30.34 inHg
- Observation at 5:53 am from SBM
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 2 |
Photographs from the investigation 3 pictures from the NTSB's docket, as the NTSB released them
Photo 1 – View of Helicopter (Photo
Photo 2 – View of Helicopter (Photo
Photo 3 – View of Main Rotor BladeThe NTSB's photographs with the NTSB's captions, at screen size. Open a picture to see it full size or to report one that should not be shown.
Documents from the investigation the NTSB's docket: the evidence folder behind the report
9 documents, released by the NTSB on November 6, 2018. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 2 | Pilot Statement | PDF, 2 pages | View Download |
| 3 | Paramedic Statement | PDF, 3 pages | View Download |
| 4 | Flight Nurse Notes | PDF, 1 page | View Download |
| 5 | Record of Conversation - Pilot | PDF, 1 page | View Download |
| 6 | Hydraulic Pack Test Results | PDF, 7 pages | View Download |
| 7 | Flight Manual Excerpt | PDF, 1 page | View Download |
| 8 | Statement of Party Representatives to NTSB Investigation - Air Methods Corporation | PDF, 1 page | View Download |
| 9 | Photo Array | PDF, 3 pages · our copy | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Connections how this case links to the rest of the register
- N1174U on the register today · the tail number may have moved to another aircraft since
- Messerschmitt-Bolkow-Blohm BK 117 12 registered today · the model family and its accident history
- Messerschmitt-Bolkow-Blohm 36 aircraft on the register
- Engine: Honeywell LTS-101 8 aircraft carry this series today · as the NTSB recorded it
- Engine: Honeywell LTS-101 8 aircraft carry this series today · as the NTSB recorded it
- Sheboygan County Memorial International · nearest airport
- Fond DU Lac County · departed from
- Accidents and incidents in Wisconsin 1,622 since 1982 · 226 in the last ten years
- Wisconsin 6,162 aircraft registered
The whole map of how records connect · these connections as data: /graph/accident/CEN18LA115.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.