WPR17FA161 · Applegate PANZL S331E
Applegate PANZL S331E · Accident: flight control system malfunction/failure while maneuvering
From Apple Valley Airport (APV) to Apple Valley Airport (APV)
Event
- NTSB case
- WPR17FA161
- 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
- 1 · 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
Applegate PANZL S331E
- Aircraft type
- Applegate PANZL S331E
- 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
- N331ST
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Apple Valley Airport (APV), Apple Valley, CATo Apple Valley Airport (APV), Apple Valley, CA
- Aircraft age
- About 12 years (built 2005)
- 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
- Maneuvering · aerobatics
- 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
- Flight control system malfunction/failure
- 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 oper/perf/capability
- Aircraft › Aircraft systems
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The private pilot was practicing her aerobatics routine. During the sixth figure of a nine-figure sequence, the pilot performed a snap roll to the right. Following the snap roll, the pilot performed a left roll as planned; however, rather than entering the next maneuver, the airplane continued to roll left. In-cockpit video indicated that, during the left roll, the right aileron exhibited a trailing-edge-down deflection consistent with a left turn. The pilot then moved her body toward the right side of the cockpit, consistent with a right control stick input. However, the airplane's rate of left roll increased, and the airplane continued to roll to the left as the pilot continued to lean toward the right. At this time, the right aileron indicated a trailing-edge-up deflection consistent with the pilot's right control stick input; the deflection of the left aileron could not be determined. The airplane continued to roll to the left until it impacted the ground.
Postaccident examination of the engine revealed no anomalies that would have precluded normal operation. Examination of the airframe revealed a break in the left aileron control assembly and one in the elevator control assembly. Both fracture surfaces of the left aileron control rod end exhibited relatively flat areas emanating from the inner diameter of the outer ring, which transitioned to angular planes adjacent to the outer diameter. One of fracture surfaces exhibited feathery features in the flat area consistent with fatigue cracking; the other fracture surface had smearing damage that obscured most of the finer features. The elevator control fracture exhibited features consistent with shear overstress.
The smearing damage indicated that the fatigue crack had been forming for some time. It is likely that the high stresses exerted on the airplane during aerobatic flight resulted in the final fracture of the left aileron control rod end due to fatigue.
Probable cause
A fatigue failure of the left aileron control rod end during aerobatic flight, which resulted in the pilot's inability to maintain control of the airplane.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR17FA161
- Event ID
- 20170722X84949
- Case number
- WPR17FA161
- 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: 7d4db7e3fc7d53bc065ac55f1880002c126670c0deba2c8fdda80bfe707a5525; retrieved 2026-09-15T06:09:11.550Z.