Bell 47G accident near La Verne, California, April 4, 1990
On April 4, 1990 at about 8:58 pm local time, a Bell 47G (helicopter), registered N739B, was substantially damaged in an accident near La Verne, California (Brackett airport). It was an instructional flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE HELICOPTER'S ROTOR SYSTEM BEING ALLOWED TO UNDERSPEED AS A RESULT OF IMPROPER USE OF FLIGHT CONTROLS BY THE DUAL STUDENT; IMPROPER SUPERVISION BY THE CERTIFIED FLIGHT INSTRUCTOR; AND DELAYED REMEDIAL ACTION BY THE CERTIFIED FLIGHT INSTRUCTOR WHICH ALLOWED THE IN FLIGHT COLLISION WITH THE RUNWAY.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 4, 1990 · about 8:58 pm local time
- Place
- La Verne, California · Brackett · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47G · all 47Gs on the register
- Registration
- N739B · registry record · serial 85
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
ACCORDING TO THE INSTRUCTOR PILOT, THE AIRCRAFT BEGAN TO VIBRATE DURING TERMINATION OF A POWER RECOVERY AUTOROTATION. HE STATED THAT WHEN THE COMMERCIALLY RATED STUDENT PILOT APPLIED POWER, THE ENGINE DEVELOPED POWER, BUT THE ROTOR RPM DECAYED. THE AIRCRAFT COLLIDED WITH THE RUNWAY. THE INSTRUCTOR PILOT WAS LATE IN TAKING THE CONTROLS AND RECOVERING THE AIRCRAFT. AN FAA AIRWORTHINESS INSPECTOR EXAMINED THE HELICOPTER AND FOUND NO PRE-IMPACT MECHANICAL MALFUNCTIONS OR FAILURES.
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: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instrument: airplane; rotorcraft: helicopter
- Flight time: 2,000 hours in all
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: unk
The aircraft
- Last inspection: inspection type not recorded; 0 hours since
- Maximum gross weight: 2,850 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming VO-435 (piston); 0 hours total
The flight
- Flight plan: none
- Runway 26R, 3,661 ft by 75 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 030° at 5 knots
- Visibility: 12 statute miles
- Sky: broken clouds at 2,500 ft; scat at 1,000 ft
- Temperature: 64°F (18°C), dew point 55°F (13°C)
- Observation at 8:46 pm from ONT, 12 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 |
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.
Other NTSB records under N739B the same tail number, which may have belonged to a different aircraft at the time
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.