Mbb BK117 accident near Strum, Wisconsin, December 25, 2018
On December 25, 2018 at about 4:15 am local time, a 2008 Mbb BK117 (helicopter), registered N145EC, was substantially damaged in an accident during landing near Strum, Wisconsin. It was flown under charter and air-taxi rules (Part 135). 3 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's failure to maintain clearance from the fire truck.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 25, 2018 · about 4:15 am local time
- Place
- Strum, Wisconsin · map
- Type
- Accident
- Injuries
- 3 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Mbb BK117 C2, built 2008
- Registration
- N145EC · no longer on the register · serial 9181
- Damage
- Substantial damage
- Flight
- Flight · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
The pilot and two crewmembers were on a night air medical flight. While on approach to the landing zone with several obstructions nearby, the pilot noticed a street sign and slowed the helicopter, which lowered the tailboom and tail rotor. The helicopter's tail rotor then struck a hose rack on a fire truck, which resulted in a loss of control and impact with the ground. The helicopter sustained substantial damage to the tail rotor. The pilot reported no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.
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
- Collision during takeoff/land during landing defining event
The NTSB's findings
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring environment › Pilot
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Altitude › Not attained/maintained
- cause Environmental issues › Physical environment › Object/animal/substance › Ground vehicle › Contributed to outcome
Pilot
- Certificate: commercial pilot
- Ratings: instrument: helicopter; rotorcraft: helicopter
- Flight time: 3,842 hours in all; 1,064 in this make and model; 42 in the last 90 days; 9 in the last 30 days; 3,842 as pilot in command; 240 on instruments
- Last flight review: October 22, 2018
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: frt
- Injury: minor injuries
Passenger
- Seat: left
- Injury: minor injuries
Passenger
- Seat: rear
- Injury: minor injuries
The aircraft
- Airframe total time: 6,055 hours
- Last inspection: approved inspection programme, December 24, 2018
- Maximum gross weight: 7,887 lb
- Seats: 5
- Landing gear: fixed
- Engine 1: Turbomeca Arriel 1E2 (turboshaft); 5,916 hours total
- Engine 2: Turbomeca Arriel 1E2 (turboshaft); 5,916 hours total
The flight
- Departed from: EAU Eau Claire WI at 3:54 am
- Destination: Strum WI
Weather at the time
- Light: night
- Visibility: 10 statute miles
- Sky: a few clouds at 8,000 ft
- Temperature: 18°F (-8°C), dew point 12°F (-11°C)
- Observation at 3:56 am from KEAU, 19 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 3 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
1 document, released by the NTSB on December 9, 2019. 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 |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
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 never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.