WPR20LA252 · Piper PA 30
Piper PA 30 · Accident: landing gear collapse
From Rogue Valley International-Medford Airport (MFR) to an unrecorded destination
Event
- NTSB case
- WPR20LA252
- 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
Piper PA 30
- Aircraft type
- Piper PA-30
- 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
- N8244Y
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Rogue Valley International-Medford Airport (MFR), Medford, ORTo not recorded
- Aircraft age
- About 55 years (built 1965)
- 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
- Landing
- 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
- Landing gear collapse
- 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 systems
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot reported that, after departure, he raised the landing gear and heard an unusual "clunk"; however, he did not observe any anomalies at the time and continued the flight. As the airplane neared the destination airport, the pilot extended the landing gear, but the landing gear did not fully extend. After troubleshooting, including attempting the emergency extension procedure, the pilot landed the airplane with the gear partially extended, during which the airplane sustained substantial damage to the keel beam and the right-wing spar. Postaccident examination revealed that the right main landing gear trunnion was fractured as the result of two fatigue cracks that had developed at a welded gusset joined to a protruding boss. Once these fatigue cracks had propagated far enough into the boss cross-section, the remainder of the part fractured by overstress, likely during the last landing. The presence of two opposite-facing fatigue cracks was consistent with reverse bending fatigue. The fatigue cracks initiated at a tapered neck-shaped area, where the gusset and trunnion were joined. The cross-sectional thickness at this location was half the thickness of the gusset and a quarter of the diameter of the boss. This configuration would introduce a stress concentration at the locations of the fatigue cracking. The trunnion boss was consistent with a heat-treated aluminum alloy. The hardness approaching the welded joint decreased, consistent with softening from the heat input. The reduced hardness would increase susceptibility to fatigue crack initiation at the areas of stress concentration. It is likely that, over time, the fatigue cracks propagated as the joint flexed or bent back and forth, and the stress concentrations at the neck-shaped region were exacerbated by the reduced mechanical properties of that region. The fracture surfaces were damaged after the accident, and, due to the amount of post-fracture damage, no reliable fatigue analysis could be performed.
Probable cause
A fatigue failure of the right main landing gear trunnion.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR20LA252
- Event ID
- 20200728X51228
- Case number
- WPR20LA252
- 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: local date, investigation status, coordinates, cause areas. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2020-06-05.
- API snapshot SHA-256: 20a4f1f35c3750d2d395d985c8624afd3e8204045d930cbf5b1e2ffad6e271a3; retrieved 2026-09-16T12:18:09.970Z.