# NTSB LAX96LA141: Scheperle Mustang II MOD, N8180T, Merced, CA, March 23, 1996

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: March 23, 1996, 12:30 local (20:30 UTC)
- Place: Merced, CA
- Coordinates: 37.349658, -120.420783 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=37.3497&lon=-120.4208&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor
- Status: Completed, report August 20, 1996
- Report: Approved by Office Director
- NTSB case key (mKey): 29394
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX96LA141
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/29394/pdf
- Page: https://openairdocs.org/ntsb/LAX96LA141

## Probable cause

a loss of engine power due to a malfunctioning thermostat valve in the liquid cooling system.

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, cruise
  - cooling system,fittings - failure (cause)
  - cooling system - pressure excessive (cause)
  - fluid,coolant - exhaustion (cause)
  - miscellaneous,engine - seized
- Forced landing, emergency descent/landing
- On ground/water collision with object, landing - roll
  - object - fence post

## Analysis

According to the pilot's statement, the converted Ford V6 automotive engine overheated and seized when a malfunctioning thermostat valve allowed excess pressure to build up inside the coolant system.  The resulting overpressure blew out a plug in a coolant outlet from the block, which is unused in this installation.  The coolant was then pumped overboard and the engine seized.  The aircraft collided with fence posts during a forced landing onto a road.

## Factual narrative

On March 23, 1996, at 1230 hours Pacific standard time, a homebuilt Scheperle Mustang II Mod, N8180T, collided with ground obstructions during a forced landing attempt near Merced, California.  The forced landing was precipitated by a loss of engine power.  The aircraft was owned and operated by the pilot and was on a personal cross-country flight from Fresno to Napa, California. Visual meteorological conditions prevailed at the time and no flight plan was filed.  The aircraft was destroyed in the collision sequence.  The pilot and passenger onboard sustained minor injuries.

According to the pilot's statement, the converted Ford V6 automotive engine overheated and seized when a malfunctioning thermostat valve allowed excess pressure to build up inside the coolant system.  The resulting over pressure blew out a plug in a coolant outlet from the block, which is unused in this installation.  The coolant was then pumped overboard and the engine seized.  The aircraft collided with fence posts during the forced landing attempt on a road.

## Aircraft

- Registration: [N8180T](https://openairdocs.org/deregistered/N8180T-2013-09-20), registration cancelled 2013-09-20, S/N S-5, built 1989 (OpenAirDocs)
- Reported make and model: SCHEPERLE MUSTANG II MOD (MUSTANG II)
- Registry model: [Scheperle C W MUSTANG II MOD](https://openairdocs.org/model/scheperle-c-w-mustang-ii-mod) (registry code 1690376) (OpenAirDocs)
- Registry engine: [Ford CONVERSION](https://openairdocs.org/engine/ford-conversion) (registry code 26701, reciprocating) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: S-5
- Airframe hours: 725
- Engines: Ford 3.8L V6 230 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Clete W. Scheperle
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, September 25, 1995, 50 hours before
- Departed: Q60, FRESNO, CA
- Destination: APC, NAPA, CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 71; commercial; airplane ratings: single-engine sea, multi-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; seat: left; flight hours: 7,300 total, 725 in this make and model, 7,000 as pilot in command, 45 in the last 90 days, 15 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 330° at 14 knots
- Visibility: 35 statute miles
- Lowest ceiling: none
- Temperature: 61 °F, dew point 37 °F
- Altimeter: 29.00 inHg

## 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 19960323004979A](https://openairdocs.org/incident/19960323004979A), Mar 23, 1996: Amtrbb MUSTANG2, Merced, CA, Destroyed. Converted ford auto engine overheated and siezed. Hit obstructions landing. Thermostat defect. Blew block plug.

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.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.