Mbb BK-117 A-4 accident near Ridgeville, South Carolina, August 9, 2007
On August 9, 2007 at about 3:20 pm local time, a Mbb BK-117 A-4 (helicopter), registered N171MU, was substantially damaged in an accident near Ridgeville, South Carolina. It was flown under charter and air-taxi rules (Part 135). No one was hurt; 5 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The EMS helicopter pilot's failure to ensure adequate obstacle clearance which resulted in the tail rotor impacting a tree during the takeoff.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 9, 2007 · about 3:20 pm local time
- Place
- Ridgeville, South Carolina · map
- Type
- Accident
- Injuries
- No one was hurt; 5 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Mbb BK-117 A-4
- Registration
- N171MU · no longer on the register · serial 7138
- Damage
- Substantial damage
- Flight
- Flight · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
The pilot said that upon landing at the scene he kept the helicopter operating with him at the controls, while the medical crew attended to the patient. After loading the patient into the helicopter, the paramedic did a walk around inspection, entered the helicopter, and called out the before-takeoff-checklist, while voicing an alert to the pilot concerning overhanging trees on the port side of the helicopter. The pilot acknowledged, and told the crew that he intended to pick the helicopter up into a hover, slide to the right, and then perform a left pedal turn to exit the scene to the west. The pilot said that while performing a left pedal turn at a hover, a vibration occurred throughout the airframe, and he immediately set the helicopter back on the ground, facing west. An EMS technician on the ground who had been observing the helicopter, stated that after the patient had been loaded into the helicopter, the helicopter was lifted into about a 3-foot hover, and then began to rotate and face into the direction of the light wind, coming from the west. After the helicopter completed the rotation into the wind, the EMS technician stated that it then began to increase altitude, and as the altitude increased the tail rotor struck a small pine tree limb that stuck out about 1 to 2 feet into, and over the westbound traffic lane closest to the median. He said he heard the change in pitch to the sound of the helicopter's engine, and also saw the tail rotor begin a slight "wobbling." At this point the EMS technician said the helicopter was about 6 to 8 feet off the ground, and he believes that the pilot sensed that something was wrong with the helicopter, and set the helicopter down firmly on the curbside lane, facing west. An examination reveal no evidence of a preaccident mechanical failure or malfunction to the helicopter or any of its systems.
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
Pilot
- Certificate: commercial pilot
- Ratings: instrument: helicopter; rotorcraft: helicopter
- Flight time: 6,009 hours in all; 3,158 in this make and model; 56 in the last 90 days; 30 in the last 30 days; 5,529 as pilot in command; 0 on instruments
- Last flight review: January 1, 2007
- Medical certificate: Class 2
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 9,392 hours
- Last inspection: approved inspection programme, August 1, 2007
- Maximum gross weight: 7,040 lb
- Seats: 6
- Landing gear: fixed
- Engine 1: Lycoming LTS-101-650 (turboshaft); 0 hours total
- Engine 2: Lycoming LTS-101-650 (turboshaft); 0 hours total
- Operator: Omniflight Helicopters Inc.,
The flight
- Departed from: CHS Charleston SC at 2:40 pm
- Destination: Ridgeville SC
Weather at the time
- Light: daylight
- Wind: from 240° at 5 knots
- Visibility: 5 statute miles
- Sky: a few clouds at 3,700 ft
- Temperature: 91°F (33°C), dew point 79°F (26°C)
- Altimeter: 29.93 inHg
- Observation at 3:56 pm from CHS, 24 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 4 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
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.