Calstar 1 Eurocopter BO-105S accident near Concord, California, June 3, 2007
On June 3, 2007 at about 10:50 pm local time, a Calstar 1 Eurocopter BO-105S (helicopter), registered N623MB, was substantially damaged in an accident near Concord, California (Concord airport). It was a positioning flight under general aviation rules (Part 91). 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 pilot's failure to maintain clearance from an object during hover. Trees were a factor.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 3, 2007 · about 10:50 pm local time
- Place
- Concord, California · Concord · map
- Type
- Accident
- Injuries
- No one was hurt; 3 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Calstar 1 Eurocopter BO-105S
- Registration
- N623MB · registry record · serial BO105CBS-5
- Damage
- Substantial damage
- Flight
- Positioning flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
During an emergency response to a roadside accident site, the helicopter experienced an in-flight collision with a tree that resulted in a main rotor strike. The Director of Flight Operations reported that the pilot had chosen a landing spot that had a tree on the southwest (SW) side of the road and a tree on the northeast (NE) side of the road. As the pilot came to a hover over the landing site, he was looking left and forward up the road to confirm that the area was secure. As he was looking toward the left front, he heard a discernable noise change from the rotor system, although there was no change in aircraft handling or any abnormal instrument indications. He looked to the right and observed that he was closer to the NE tree than he wanted to be. He then observed a broken branch on the NE tree. After a normal shut down, a visual inspection showed damage to the outer three to five inches of the trailing edge of the three main rotor blades.
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: single-engine land; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 7,700 hours in all; 1,700 in this make and model; 20 in the last 90 days; 3 in the last 30 days
- Medical certificate: Class 2
The aircraft
- Landing gear: fixed
- Engine 1: Rolls-Royce CAE 821234 (turboshaft); 0 hours total
- Engine 2: Rolls-Royce CAE 835231 (turboshaft); 0 hours total
The flight
- Departed from: CCR Concord CA
Weather at the time
- Light: daylight
- Wind: from 250° at 15 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 25,000 ft
- Temperature: 63°F (17°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 3 |
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.