# NTSB ATL91LA178: Piper PA-25-235, N7509Z, Brewton, AL, September 21, 1991

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: September 21, 1991, 08:30 local (14:30 UTC)
- Place: Brewton, AL
- Coordinates: 31.109291, -87.069671 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=31.1093&lon=-87.0697&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed, report April 23, 1993
- Report: Approved by Office Director
- Safety recommendations: Yes
- NTSB case key (mKey): 8475
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL91LA178
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/8475/pdf
- Page: https://openairdocs.org/ntsb/ATL91LA178

## Probable cause

THE INFLIGHT SEPARATION OF THE LEFT WING RESULTING FROM CORROSION OF THE WING FRONT SPAR FITTING ASSEMBLY. A FACTOR WAS INADEQUATE MAINTENANCE PROCEDURES.

## Sequence of events

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

- Airframe/component/system failure/malfunction, maneuvering - aerial application
  - wing - failure,total
  - wing,wing attachment fitting - corroded (cause)
  - maintenance,inspection - inadequate, manufacturer (contributing factor)
- Loss of control - in flight, maneuvering - aerial application
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE LEFT WING SEPARATED FROM THE AIRFRAME WHEN ONE OF THE TWO WING FRONT SPAR FITTING CLEVIS EARS FAILED. EXAMINATION OF THE FAILED COMPONENT UNCOVERED CORROSION BETWEEN THE SECTIONS MAKING UP THE WELDED CLEVIS EAR. THE ACCUMULATION OF CORROSION IS ATTRIBUTED TO CHEMICAL SPRAYED FROM THE AIRPLANE OVER A LONG PERIOD OF TIME. ADDITIONALLY, THERE WAS NO INSPECTION PROCEDURE SPECIFIED FOR THIS AREA OF THE WING FITTING. SUBSEQUENTLY, THE NTSB ISSUED A RECOMMENDATION REQUESTING AN INSPECTION PROCEDURE TO PREVENT THE FORMATION OF CORROSION BETWEEN THE LAYERS OF CLEVIS MATERIAL.

## Aircraft

- Registration: [N7509Z](https://openairdocs.org/deregistered/N7509Z-2013-05-08), registration cancelled 2013-05-08, S/N 25-3543, built 1965 (OpenAirDocs)
- Reported make and model: PIPER PA-25-235
- Registry model: [Piper PA-25-235](https://openairdocs.org/model/piper-pa-25-235) (registry code 7102504) (OpenAirDocs)
- Registry engine: [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series) (registry code 41532, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: PA25-3543
- Airframe hours: 10700
- Engines: LYCOMING O-540B2B5 235 horsepower reciprocating
- Damage: Destroyed
- Fire: On-Ground
- Flight: Aerial application, Part 137
- Operator: Wallace Flying Service
- Registered owner: Wallace Flying Service
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, April 19, 1991, 200 hours before
- Departed: NONE, MC CULLOUGH, AL

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 54; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: front; flight hours: 12,000 total, 8,000 in this make and model, 11,800 as pilot in command, 300 in the last 90 days, 200 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 40° at 10 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 63 °F
- Altimeter: 30.00 inHg
- Observed at: MOB, 30 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 19910921042259A](https://openairdocs.org/incident/19910921042259A), Sep 21, 1991: Piper PA25235, Brewton, AL, Destroyed. Left wing attachment fitting failed during spray run pull up. Wing seperated. Attach fitting corroded and cracked.

## Other investigations on N7509Z (2)

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 MIA77DKJ79](https://openairdocs.org/ntsb/MIA77DKJ79), Aug 25, 1977: Piper PA-25 (N7509Z), Mccullough, AL, substantial damage
- [NTSB MIA71DKJ53](https://openairdocs.org/ntsb/MIA71DKJ53), Apr 20, 1971: Piper PA-25 (N7509Z), Mccullough, AL, 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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