Schweizer Aircraft CORP G-164B accident near Yuba City, California, July 9, 2011
On July 9, 2011 at about 9:30 pm local time, a Schweizer Aircraft CORP G-164B, registered N7503L, was substantially damaged in an accident during initial climb near Yuba City, California. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
High-cycle fatigue on the 1st-stage compressor blade retaining ring, which resulted in the ring’s fracture and a subsequent loss of engine power.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 9, 2011 · about 9:30 pm local time · cases in 2011
- Place
- Yuba City, California · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Schweizer Aircraft CORP G-164B · all G-164Bs on the register
- Registration
- N7503L · registry record · serial 826B
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that, during the initial climb, he heard a "loud pop" and observed fire coming from both exhaust stacks before the engine lost power. He subsequently made an off-airport landing to an adjacent road. During the landing, the airplane slid into a ditch, the landing gear sheared off, and the airplane nosed over. A postaccident engine examination revealed that the blade retaining ring of the 1st-stage compressor blades had fractured into several pieces; about 30 percent of the ring was not recovered. A metallurgical examination of the recovered sections of the retaining ring revealed that all but two of the fractures were due to ductile overload. An examination of the nonoverload fractures revealed fatigue originating from the rivet hole areas, which was indicative of high-cycle fatigue. The power section had been overhauled 747 hours before the accident. According to the overhaul manual current at the time of the overhaul, the blade retaining ring was an on-condition inspection item and not required to be replaced at overhaul. The fatigue fracture of the 1st-stage compressor blade retaining ring likely affected the engine's ability to produce power.
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 engine power (total) during initial climb defining event
- Off-field or emergency landing during landing (landing roll)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Compressor section › Fatigue/wear/corrosion other cases naming the engine
- Environmental issues › Physical environment › Terrain › Rough terrain › Effect on equipment
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; rotorcraft: helicopter
- Flight time: 11,433 hours in all; 5,533 in this make and model; 250 in the last 90 days; 200 in the last 30 days; 11,433 as pilot in command
- Last flight review: March 18, 2011
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: sngl
- Injury: no injuries
The aircraft
- Airframe total time: 10,282 hours
- Last inspection: annual inspection, April 19, 2011; 373 hours since
- Maximum gross weight: 5,200 lb
- Seats: 1
- Landing gear: fixed
- Engine: P&W PT6A-34 (turboprop); 8,503 hours total
- Operator: Onstott Dusters INC
The flight
- Departed from: Yuba City CA at 9:30 pm
- Destination: Yuba City CA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 190° at 16 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 91°F (33°C), dew point 61°F (16°C)
- Altimeter: 29.75 inHg
- Observation at 9:53 pm from KMYV
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
5 documents, released by the NTSB on July 25, 2014. 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 | Pratt and Whitney Canada Report | PDF, 35 pages | View Download |
| 3 | Pratt and Whitney Canada to NTSB Letter | PDF, 1 page | View Download |
| 4 | Engine Logbook Excerpts | PDF, 8 pages | View Download |
| 5 | Pwc Overhaul Manual Excerpts | PDF, 3 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Other NTSB records under N7503L the same tail number, which may have belonged to a different aircraft at the time
Connections how this case links to the rest of the register
- N7503L on the register today · the tail number may have moved to another aircraft since
- Schweizer Aircraft Corp G-164 64 registered today · the model family and its accident history
- Engine: P&W PT6A-34 42 aircraft carry this series today · as the NTSB recorded it
- Accidents and incidents in California 9,080 since 1982 · 1,097 in the last ten years
- California 27,761 aircraft registered
- Other NTSB records under N7503L 2 records · the number may have belonged to another aircraft at the time
The whole map of how records connect · these connections as data: /graph/accident/WPR11LA320.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.