Enstrom F 28C accident near Ontario, California, July 19, 2017
On July 19, 2017 at about 5:10 pm local time, a Enstrom F 28C (helicopter), registered N5697B, was substantially damaged in an accident during approach (VFR pattern downwind) near Ontario, California (Chino Airport). It was an instructional flight under general aviation rules (Part 91). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The student pilot's mismanagement of the main rotor rpm, which resulted in low rotor rpm, a high descent rate, and a subsequent hard landing.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 19, 2017 · about 5:10 pm local time
- Place
- Ontario, California · Chino Airport · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Enstrom F 28C · all F 28Cs on the register
- Registration
- N5697B · no longer on the register · serial 505-2
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The solo student pilot reported that he entered the downwind leg to set up for the helicopter's first landing of the day. When abeam the touchdown location, he conducted the prelanding checks with no anomalies noted. Before turning onto the base leg, the pilot lowered the collective, reduced the throttle, and started to descend about 100 ft per minute. During the descent, he observed that the engine rpm was slightly above 2,900 rpm. He reduced the throttle, and the rpm reduced slightly; however, it again increased to 2,900 rpm, and the manifold pressure was about 10 inches of mercury. When the helicopter was about 400 ft above ground level, the pilot heard the engine sound increase, and he observed that the engine rpm had increased to between about 3,300 and 3,500 rpm. The helicopter was unable to reach the runway, so the pilot continued to descend it toward a pasture, and it landed hard in the dirt. A postaccident airframe and engine examination and subsequent engine run revealed no preimpact anomalies that would have precluded normal operation. The observed damage to the main rotor blades was consistent with blade coning, a condition indicative of low main rotor rpm. It is likely that the student pilot mismanaged the main rotor rpm during the descent, which resulted in a low rotor rpm and a high descent rate during landing.
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
- Loss of control in flight during approach (VFR pattern downwind) defining event
- Off-field or emergency landing during approach (VFR pattern downwind)
The NTSB's findings
- cause Personnel issues › Task performance › Use of equip/info › Aircraft control › Student/instructed pilot
- cause Personnel issues › Task performance › Use of equip/info › Use of equip/system › Student/instructed pilot
- cause Aircraft › Aircraft propeller/rotor › Main rotor system › Main rotor blade system › Incorrect use/operation
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Descent rate › Not attained/maintained
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Prop/rotor parameters › Not attained/maintained
Pilot
- Certificate: student
- Flight time: 33 hours in all; 33 in this make and model; 30 in the last 90 days; 8 in the last 30 days; 1 as pilot in command
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 3,715 hours
- Last inspection: 100-hour inspection, May 5, 2017; 20 hours since
- Maximum gross weight: 2,350 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming HIO-360-E1AO (piston); 3,715 hours total
The flight
- Departed from: CNO Ontario CA at 5:10 pm
- Destination: CNO Ontario CA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 280° at 7 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 15,000 ft
- Temperature: 84°F (29°C), dew point 61°F (16°C)
- Altimeter: 30.01 inHg
- Observation at 4:53 pm from CNO, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
4 documents, released by the NTSB on November 2, 2017. 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 |
| 2 | Airframe and Engine Examination | PDF, 7 pages | View Download |
| 3 | Statement of Party Representatives to NTSB Investigation | PDF, 2 pages | View Download |
| 4 | Release of Aircraft Wreckage, NTSB Form 6120.15 | PDF, 1 page | 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.