# NTSB ATL91LA125: Piper PA-12, N4401M, Myrtle Beach, SC, July 8, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 8, 1991, 13:15 local (17:15 UTC)
- Place: Myrtle Beach, SC
- Coordinates: 33.690711, -78.889266 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.6907&lon=-78.8893&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report September 28, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 8429
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL91LA125
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/8429/pdf
- Page: https://openairdocs.org/ntsb/ATL91LA125

## Probable cause

THE FAILURE OF THE NUMBER 4 CYLINDER EXHAUST VALVE. FACTORS IN THE ACCIDENT WERE THE LACK OF A SUITABLE LANDING SITE AND THE WATER DITCHING.

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, cruise
  - single engine aircraft
  - engine assembly,valve,exhaust - fractured (cause)
- Forced landing, descent - emergency
  - terrain condition - none suitable (contributing factor)
- Hard landing, descent
- In flight collision with terrain/water, descent

## Analysis

AFTER ABOUT 30 MINUTES OF OPERATION, DURING A BANNER TOW FLIGHT, THE ENGINE BEGAN TO RUN ROUGHLY.  THE AIRPLANE WAS AT 300 FEET OVER THE OCEAN ADJACENT TO A PUBLIC BEACH.  UNABLE TO MAINTAIN ALTITUDE THE PILOT DITCHED IN THE OCEAN TO AVOID THE CROWDED BEACH.  SUBSEQUENT EXAMINATION OF THE ENGINE REVEALED THAT THE NO. 4 CYLINDER EXHAUST VALVE HAD BROKEN AT THE PISTON END.  THE ENGINE HAD 1939 HOURS SINCE THE LAST OVERHAUL.

## Aircraft

- Registration: [N4401M](https://openairdocs.org/aircraft/N4401M), registered now, S/N 12-3341, built 1947 (OpenAirDocs)
- Reported make and model: PIPER PA-12
- Registry model: [Piper PA-12](https://openairdocs.org/model/piper-pa-12) (registry code 7101202) (OpenAirDocs)
- Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 12-3341
- Engines: LYCOMING O-320 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Other work use, Part 91
- Operator: Sky Signs, Inc.
- Registered owner: Emu, Inc
- Last inspection: 100 hour, July 6, 1991, 9 hours before
- Departed: NONE, CONWAY, SC

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 26; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; flight hours: 761 total, 120 in this make and model, 280 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 4 statute miles
- Lowest ceiling: 25,000 ft broken
- Temperature: 95 °F, dew point 72 °F
- Altimeter: 30.00 inHg
- Observed at: CRE, 1 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 19910708026579A](https://openairdocs.org/incident/19910708026579A), Jul 8, 1991: Piper PA12, Myrtle Beach, SC, Substantial damage. Rough engine. Dropped banner and ditched in ocean offshore. NR4 cylinder exhaust valve broke at piston end.

## Other investigations on N4401M (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 SEA72DYA41](https://openairdocs.org/ntsb/SEA72DYA41), Jun 28, 1972: Piper PA-12 (N4401M), Middleton, ID, 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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