MKC89FA191 · Piper PA-20
Piper PA-20 · Accident: airframe, component or system failure en route
From 21Y · Moose Lake, MN to an unrecorded destination
Event
- NTSB case
- MKC89FA191
- 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
- 2 · all aircraft and ground
- Ground fatalities
- 0
- 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-20
- Aircraft type
- Piper PA-20
- 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
- N2841P
- Operator
- Prachar, Kenneth M · private individual
- Onboard fatalities
- Unknown
- Route
- From 21Y · Moose Lake, MNTo not recorded
- Aircraft age
- Not recorded
- 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
- En route · cruise
- First occurrenceThe 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
- Airframe, component or system failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Other maintenance personnel › Maintenance, inspection, inadequate
- Wing, bracing strut › Corroded
- Wing, bracing strut › Failure, total
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE ACFT (PIPER PA-22, CONVERTED TO A PA-20, IAW STC SA45AM) WAS BEING USED TO PROVIDE A BIENNIAL FLT REVIEW FOR THE OWNER/PLT (CONSIDERED AS PIC ON THIS FLT). DRG FLT, THE RGT WING FOLDED BACK OVER THE FUSELAGE & THE ACFT CRASHED. AN EXAM OF THE WRECKAGE REVEALED THE FWD LIFT STRUT FOR THE RGT WING HAD FAILED IN AN AREA OF SEVERE CORROSION. THE FAILUREOCCURRED AT THE LOWER PART OF THE LIFT STRUT NEAR THE FUSELAGE ATTACHMENT POINT. AN EXAM OF THE ANNUAL INSPN CHECKLIST INDCD ALL APPLICABLE AIRWORTHINESS DIRECTIVES (AD'S) WERE COMPLIED WITH AS OF 7/21/89 & THAT THE LIFT STRUTS WERE VISUALLY INSPD AT THE ANNUAL INSPN. THE ACFT LOGBOOK SHOWED THAT AD 77-03-08 (REQUIRING MECHANICAL TESTING OF THE LIFT STRUT FOR EVIDENCE OF CORROSION AT 5 YR INTERVALS) HAD BEEN COMPLIED WITH IN JULY 1988. THE AROMA OF LINSEED OIL WAS NOTED IN ALL LIFT STRUTS, BUT POLYMERIZED LINSEED OIL WAS FOUND IN THE RGT & LEFT REAR STRUTS. INTERNAL CORROSION HAD PERFORATED THE RGT FWD LIFT STRUT PRIOR TO ITS FAILURE.
Probable cause
SEVERE CORROSION OF THE LOWER FORWARD LIFT STRUT FOR THE RIGHT WING, INADEQUATE INSPECTION OF THE LIFT STRUT BY MAINTENANCE PERSONNEL, AND SUBSEQUENT FAILURE OF THE LIFT STRUT, WHICH RESULTED IN AN OVERLOAD FAILURE (FOLDING BACK) OF THE WING. RELATED FACTORS WERE: INADEQUATE INSPECTION PROCEDURES PROVIDED BY THE MANUFACTURER & INADEQUATE SURVEILLANCE BY THE FAA.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record MKC89FA191
- Event ID
- 20001213X29206
- Case number
- MKC89FA191
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1989-08-30.
- API snapshot SHA-256: 04753bc8e87521041a37b90f751b87d13052e2fc083344d62f67607e82433e69; retrieved 2026-09-21T03:10:29.551Z.