Robinson R22 Beta accident near El Monte, California, September 14, 2007
On September 14, 2007 at about 6:15 pm local time, a Robinson R22 Beta (helicopter), registered N877HF, was substantially damaged in an accident near El Monte, California. 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
a failure of the main rotor drive system V-belts due to damage sustained when the alternator drive belt failed and pieces of that belt got between the main drive belts and their associated pulleys. A contributing factor was the uneven terrain encountered in the forced landing.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 14, 2007 · about 6:15 pm local time
- Place
- El Monte, California
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Robinson R22 Beta · all R22 Betas on the register
- Registration
- N877HF · no longer on the register · serial 3589
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
While in cruise flight about 1,700 feet agl, the flight instructor heard a loud "bang" from the back of the helicopter. The alternator warning light illuminated, and he initiated the alternator emergency procedure. He noticed the engine's rpm was fluctuating with the main rotor rpm indicating high and the engine rpm low. He entered an autorotation and landed on uneven terrain; the main rotor struck the tail boom, and the helicopter rolled over onto its left side. The helicopter was examined by a Safety Board investigator. The two main drive V-belts were located in the drive compartment with one positioned on the drive pulleys in the middle slot (between the normal operating positions for the forward and aft belts), and the other was located completely off of the drive pulleys. Both belts exhibited damage on the inside including scratch marks, material and color transfers, and gouges consistent with damage by a rubber based foreign object. Rubber and color transfer in a transverse orientation inconsistent with the drive belts was noted on the upper and lower pulleys. The alternator belt was missing and not recovered. The clutch assembly was located in the up position with the actuator fully extended, and the safety stop activated. The oil cooler sustained damage to the outer fins. Rubber transfer was located on the oil cooler, starter, oil lines, and exhaust tube on a plane with the alternator belt's rotation. The alternator belt is located directly below the lower main drive pulley. No other preimpact anomalies with either the airframe or engine were discovered. As a result of this investigation Robinson is changing the specification for the alternator drive belt.
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
Flight instructor
- Certificate: flight instructor, commercial pilot
- Ratings: instructor: helicopter; rotorcraft: helicopter
- Flight time: 466 hours in all; 466 in this make and model; 86 in the last 90 days; 9 in the last 30 days; 228 as pilot in command; 8 on instruments
- Last flight review: January 1, 2006
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: left
- Injury: no injuries
Dual student
- Flight time: 1 hours in all; 1 in this make and model
- Medical certificate: None
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 1,708 hours
- Last inspection: 100-hour inspection, August 1, 2007; 41 hours since
- Maximum gross weight: 1,370 lb
- Seats: 2
- Landing gear: fixed
- Engine: Textron Lycoming O-360-J2A (piston); 0 hours total
- Operator: Universal Air Academy
The flight
- Departed from: EMT El Monte CA at 6:00 pm
- Destination: EMT El Monte CA
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 77°F (25°C), dew point 54°F (12°C)
- Altimeter: 29.95 inHg
- Observation at 5:47 pm from KCQT, 10 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.
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.