# NTSB MKC89FA063: Piper PA-18, N7580D, Jacksonville, AR, February 25, 1989

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: February 25, 1989, 15:15 local (21:15 UTC)
- Place: Jacksonville, AR
- Coordinates: 34.859813, -92.119132 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=34.8598&lon=-92.1191&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed, report October 26, 1989
- Report: Approved by Office Director
- Safety recommendations: Yes
- ADs cited in the narratives: AD 77-03-08 (OpenAirDocs)
- NTSB case key (mKey): 34674
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC89FA063
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/34674/pdf
- Page: https://openairdocs.org/ntsb/MKC89FA063

## Probable cause

SEVERE CORROSION OF THE LEFT FORWARD WING LIFT STRUT WHICH RESULTED IN THE IN-FLIGHT SEPARATION OF THE LEFT WING. A CONTRIBUTING FACTOR WAS INADEQUACY OF THE APPLICABLE SERVICE BULLETIN.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, cruise
  - maintenance,service bulletin/letter - inadequate, manufacturer (contributing factor)
  - wing,bracing strut - corroded (cause)
  - wing - separation
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

TWO WITNESSES HEARD A LOUD NOISE FROM THE ACFT AS IT WAS IN FLT. THEY LOOKED UP & NOTED THE LEFT WING OF THE ACFT HAD FAILED. SUBSEQUENTLY, THE ACFT SPUN TO THE GND & CRASHED IN A WOODED AREA. AN EXAM OF THE WRECKAGE REVEALED THE LEFT FORWARD LIFT STRUT HAD FAILED, APRX 6 INCHES FROM WHERE IT WAS ATTACHED TO THE FUSELAGE. A METALLURGICAL EXAM REVEALED THE INSIDE OF THE STRUT HAD BECOME CORRODED & THE STRUT HAD FAILED IN AN AREA WHERE ITS WALL HAD CORRODED TO A KNIVE EDGE (LESS THAN 0.001 INCH). THE THICKNESS OF THE NON-CORRODED PORTION OF THE WALL WAS 0.38 INCH. A CHEMICAL TEST OF THEINSIDE SURFACE SHOWED THE PRESENCE OF A CORROSION INHIBITOR (VAL-OIL) IN THE NON-CORRODED AREAS. HOWEVER, NO INHIBITOR COULD BE FND WHERE SEVERE CORROSION HAD OCCURRED. TWO FAINT LINES RESEMBLING WATER MARKS WERE FND IN THE STRUT. LOG BOOKENTRIES SHOWED THAT AD 77-03-08 & PIPER SVC BULLETIN #528B HAD BEEN COMPLIED WITH. A TOXICOLOGY CHECK OF THE PLT'S BLOODWAS POSITIVE FOR ALCOHOL (0.04%), BUT THERE WAS NO INDCN THAT THIS WAS RELATED TO THE STRUT FAILURE.

## Aircraft

- Registration: [N7580D](https://openairdocs.org/deregistered/N7580D-2015-05-04), registration cancelled 2015-05-04, S/N 18-5874, built 1957 (OpenAirDocs)
- Reported make and model: PIPER PA-18
- Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs)
- Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 18-5874
- Engines: LYCOMING O-320 150 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Operator: Scott Aero Service Inc.
- Registered owner: Scott Aero Service Inc
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, January 16, 1989, 6 hours before
- Departed: PERRY, AR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 40; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: front; toxicology performed; flight hours: 15,000 total

## Weather

- Conditions: Visual (VMC), Day
- Wind: 220° at 12 knots
- Visibility: 10 statute miles
- Lowest ceiling: 4,500 ft broken
- Temperature: 55 °F, dew point 39 °F
- Altimeter: 30.00 inHg
- Observed at: LIT, 22 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19890225002569A](https://openairdocs.org/incident/19890225002569A), Feb 25, 1989: Piper PA18150, Jacksonville, AR, Destroyed, 2 fatal. Left wing snapped with loud noise in flight. Corroded wing strut failed. Pilot tested positive for alcohol.

## Other investigations on N7580D (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB FTW68D0527](https://openairdocs.org/ntsb/FTW68D0527), Apr 5, 1968: Piper PA-18 (N7580D), Bismarck, AR, substantial damage

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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