WPR15FA121 · Ryan Aeronautical ST3KR
Ryan Aeronautical ST3KR · Accident: loss of engine power (total) during initial climb
From Santa Monica Municipal Airport (SMO) to Santa Monica Municipal Airport (SMO)
Event
- NTSB case
- WPR15FA121
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Ryan Aeronautical ST3KR
- Aircraft type
- Ryan Aeronautical ST3
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N53178
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Santa Monica Municipal Airport (SMO), Santa Monica, CATo Santa Monica Municipal Airport (SMO), Santa Monica, CA
- Aircraft age
- About 73 years (built 1942)
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Initial climb
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of engine power (total)
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Tree(s)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Aircraft › Aircraft power plant
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
Shortly after takeoff, the pilot advised the air traffic control tower controller that the engine had lost power, and the pilot requested an immediate return to the airport. The pilot initiated a left turn toward the airport; however, during the approach, he realized that the airplane was unable to reach the runway. Subsequently, the airplane struck the top of a tree and then impacted the ground in an open area of a golf course.
A postaccident examination of the airplane's engine revealed that the carburetor's main metering jet was unscrewed from its seat and rotated 90 degrees. The unseated jet would have allowed an increased fuel flow through the main metering orifice, producing an extremely rich fuel-to-air ratio, which would have resulted in the loss of engine power. It is likely that, over time, the jet gradually loosened from its seat, which allowed it to eventually rotate 90 degrees. No further mechanical failures or malfunctions were revealed that would have precluded normal operation.
A review of the airplane's maintenance records indicated that the carburetor was rebuilt during the airplane's restoration about 17 years before the accident. The carburetor maintenance instruction manual contained no pertinent instructions for the installation of the jet assemblies. Further, no maintenance entries in the engine logbook regarding carburetor maintenance were found. Had the carburetor maintenance instruction manual identified a means to ensure the security of the main metering jet, it is unlikely that the jet would have become unseated. There was no record of maintenance personnel inspecting the carburetor jets during the previous 17 years nor was there a requirement to do so.
The front and rear seats of the airplane were equipped with non-factory-installed shoulder harnesses. The pilot's shoulder harness was installed by mounting the end of the restraint to the lower portion of the seatback assembly, which was made of thin aluminum. No reinforcement material or doublers were installed at or around the attachment bolt hole in the seatback. The lack of reinforcement allowed the attachment bolt, washers, and stop nut to be pulled upward and through the seatback structure during the impact sequence, which resulted in the pilot's loss of shoulder harness restraint. It is likely that the improperly installed shoulder harness contributed to the severity of the pilot's injuries.
As a result of this investigation, the NTSB is working with the pilot community to inform them of the lessons learned from this accident: the security of the carburetor's main metering jet and the security of the shoulder harness are both critical aspects of aviation safety.
Probable cause
A total loss of engine power during initial climb when the carburetor main metering jet became unseated, which led to an extremely rich fuel-to-air ratio. Contributing to the accident was the lack of adequate carburetor maintenance instructions. Contributing to the severity of the pilot's injuries was the improperly installed shoulder harness.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR15FA121
- Event ID
- 20150305X93207
- Case number
- WPR15FA121
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 4cd0543f6f9a80aa8b56f093413b96c1fda1b9d66403885e217200ea56dcd585; retrieved 2026-09-16T02:07:40.874Z.