FTW04LA124

NTSB accident investigation · Aeronca 7AC · Fort Stockton, TX · May 8, 2004

Accident · No injuriesLimited investigationFinal report
Date
May 8, 2004, 18:22 local (23:22 UTC)
Place
Fort Stockton, TX
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N3708EAeronca 7AC
Weather
Visual (VMC) · Day
Status
Completed · report September 29, 2004
Report
Approved by Office Director
Parties
Lubbock FSDO
FAA report
20040508007039A
Case key
59180

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

The pilot's improper leaning of the fuel/air mixture in-flight, which resulted in a loss of engine power. Factor were the wind gusts and the crosswind.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Loss of engine power(total) - nonmechanicalCruise
Mixture - improper use ofPilot in commandCause
Forced landingDescent - emergency
On ground/water collision with objectLanding
Object - fence post
Object - tree(s)
Weather condition - crosswindFactor
Weather condition - gustsFactor

Analysis

The 821-hour commercial pilot lost engine power while in cruise flight at 2,500 feet mean sea level approximately 25 miles west of his intended destination. While en route, he noticed the oil temperature gauge indicated 240 degrees (red line was 145 degrees). The pilot reduced engine rpm from 2,400 to 2,200, and increased the airplane's mixture setting. The oil temperature began to decrease. Shortly after, the engine suddenly began to lose power. The pilot increased the mixture setting to "full rich", and applied carburetor heat, but the engine continued to lose power. He was unable to maintain altitude and executed a forced landing to a service road on Interstate 10. Upon landing, the pilot was unable to keep the airplane straight due to the strong, gusting crosswinds and collided with a metal fence post and mesquite trees. Examination of the top and bottom spark plugs revealed the #2 and #4 plugs were oily, and the #1 and #3 plugs appeared white in color. The oil, which was changed approximately 8 hours before the accident, was dark in color. When asked how this accident could have been prevented, the pilot reported, "I probably leaned engine too much too long causing the oil temp[erature] to reach 240 degrees. Run aircraft more rich to provide better cooling to internal combustion chambers." Weather reported at an airport about 17 miles from the accident site were reported as wind from 130 degrees at 17 knots gusting to 24 knots.

Factual narrative

On May 8, 2004, approximately 1822 central daylight time, an Aeronca 7AC single-engine airplane, N3708E, registered to and operated by a private individual, sustained substantial damage during a forced landing to a road following a loss of engine power near Fort Stockton, Texas. The commercial pilot and the passenger were not injured. A visual flight rules (VFR) flight plan was filed for the cross-country flight that departed Culberson County Airport (VHN) near Van Horn, Texas, about 1710, destined for Fort Stockton-Pecos County Airport (FST), Pecos, Texas. Visual meteorological conditions prevailed for the personal flight conducted under 14 Code of Federal Regulations Part 91.

In a written statement, the 821-hour pilot reported that while in cruise flight at 2,500 feet mean sea level approximately 25 miles west of Fort Stockton, he noticed the oil temperature gauge indicated 240 degrees (red line was 145 degrees). He reduced engine rpm from 2,400 to 2,200, and increased the airplane's mixture setting. The oil temperature began to decrease. Shortly after, about 17 miles west of Fort Stockton, the engine suddenly began to lose power. The pilot increased the mixture setting to "full rich", and applied carburetor heat, but the engine continued to lose power. He was unable to maintain altitude and executed a forced landing to a service road on Interstate 10. Upon landing, the pilot was unable to keep the airplane straight due to the strong, gusting crosswinds and collided with a metal fence post and mesquite trees. The pilot reported that the right wing and fuselage sustained structural damage.

A Federal Aviation Administration inspector performed an examination of the engine. According to the inspector, the engine was manually rotated, and compression and valve train continuity were established for each cylinder. The top and bottom spark plugs were removed; the #2 and #4 plugs appeared to be oily, and the #1 and #3 plugs appeared white in color. The oil, which was changed approximately 8 hours before the accident, was dark in color.

When asked how this accident could have been prevented, the pilot reported, "I probably leaned engine too much too long causing the oil temp[erature] to reach 240 degrees. Run aircraft more rich to provide better cooling to internal combustion chambers."

Weather at Fort Stockton at 1753 was reported as wind from 130 degrees at 17 knots gusting to 24 knots, visibility 10 miles, and clear skies.

Aircraft

Registration
N3708E
Reported as
Aeronca 7AC
Category
Airplane
Serial number
7AC-7009
Airframe hours
1,985
Engine
Lycoming O-235, 108 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Registered owner
Stanley Hoffpauir
Airworthiness certificate
Standard, Normal
Last inspection
Annual · January 14, 2004 · 6 hours before
Departed
VHN · Van Horn, TX
Destination
FST · Fort Stockton, TX
Flight plan
VFR

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
62
Injuries
None
Certificate
Commercial
Medical
Class 3, Valid Medical--w/ waivers/lim
Last flight review
December 26, 2003
Seat
Front
Flight hours
821 total · 81 in this make and model

Weather

Conditions
Visual (VMC) · Day
Wind
130° at 17 knots, gusting 24
Visibility
10 statute miles
Lowest ceiling
None
Temperature
86 °F, dew point 59 °F
Altimeter
29.94 inHg
Observed at
FST, 25 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.

Other investigations on N3708E · 1

Matched to the same aircraft by N-number and date.