DEN04LA110

NTSB accident investigation · American AA-1 · Guernsey, WY · July 25, 2004

Accident · Serious injuriesLimited investigationFinal report
Date
July 25, 2004, 10:30 local (16:30 UTC)
Place
Guernsey, WY
Injuries
1 serious
Damage
Destroyed
Phase of flight
Initial climb
Aircraft
N5667LAmerican AA-1
Weather
Visual (VMC) · Day
Status
Completed · report June 8, 2005
Report
Approved by Office Director
Parties
FAA Flight Standards Field Office
Case key
59732

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

On this page

Probable cause

the pilot's inadequate use of carburetor heat which resulted in the formation of carburetor ice and loss of engine power. Factors contributing to the accident were weather conditions conducive for carburetor icing, and a lack of suitable terrain for a forced landing.

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 powerTakeoff - initial climb
Carburetor heat - inadequatePilot in commandCause
Fuel system,carburetor - iceCause
Weather condition - carburetor icing conditionsFactor
Forced landingDescent - emergency
On ground/water encounter with terrain/waterEmergency landing
Terrain condition - none suitableFactor
Terrain condition - high vegetation
Object - fence

Analysis

According to the pilot, he just departed and was climbing. The pilot stated that the "engine started sputtering, and the tachometer went to 2200 rpm" and he was unable to maintain altitude. The pilot elected to land straight ahead due to "flatter" terrain. The airplane impacted a barbed wire fence and sage brush during the forced landing, causing substantial damage. The aviation routine weather report (METAR) reported the temperature as 77 degrees Fahrenheit (F) and the dewpoint was 54 degrees F. According to the Carburetor Icing Chart, these conditions are conducive for "serious icing at glide power." The contents of the airplane were weighed to calculate a weight and balance. The total weight of the airplane was calculated to be 1,580 pounds and the center of gravity was calculated to be 3 inches aft the most aft center of gravity limit.

Factual narrative

On July 25, 2004, at 1030 mountain daylight time, an American AA-1, N5667L, piloted by a private pilot, was destroyed when it impacted terrain during a forced landing near Camp Guernsey Airport (7V6), Guernsey, Wyoming. Visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted under the provisions of Title 14 CFR Part 91 without a flight plan. The pilot sustained serious injuries. The cross-country flight was originating at the time of the accident and was en route to Oshkosh, Wisconsin.

According to the accident report submitted by the pilot, he had just departed from runway 14 and was climbing. The pilot stated that the "engine started sputtering, and the tachometer went to 2200 rpm" and he was unable to maintain altitude. The pilot elected to land straight ahead due to "flatter" terrain. The airplane impacted a barbed wire fence and sage brush during the forced landing, separating the nose gear and both wings. The engine mounts separated on the upper left side of the firewall, the propeller separated at the hub and then firewall buckled. The both wings were crushed aft longitudinally and separated from the fuselage, the canopy was crushed and fragmented and the cabin area was crushed in on the left side.

According to the FAA inspector who traveled to the scene, the contents of the airplane were weighed to calculate a weight and balance. The total weight of the airplane was calculated to be 1,580 pounds and the center of gravity was calculated to be 3 inches aft the most aft center of gravity limit.

On November 4, 2004, the engine was examined, under the auspices of the NTSB, in Greeley, Colorado. The engine was checked for continuity and compression and the magnetos were checked for spark. During a compression check, conditions consistent with lower compression were present in the #1 cylinder. According to the engine logbook, the airplane underwent an annual inspection on July 14, 2004. During the inspection, the cylinders produced the following compression: #1 66/80, #2 70/80, #3 78/80, and #4 78/80. The FAA inspector stated these results are within acceptable tolerances.

The Torrington aviation routine weather report (METAR), 22 miles south east of Guernsey reported the temperature as 77 degrees Fahrenheit (F) and the dewpoint was 54 degrees F. According to the Carburetor Icing Chart, these conditions are conducive for "serious icing at glide power."

Aircraft

Registration
N5667L
Reported as
American AA-1
Category
Airplane
Serial number
AA1-0067
Airframe hours
2,377.9
Engine
Lycoming O-235-C2C, 108 horsepower, reciprocating
Damage
Destroyed
Flight
Personal · Part 91
Airworthiness certificate
Standard, Normal
Last inspection
Annual · July 14, 2004 · 11.6 hours before
Departed
7V6 · Guernsey, WY
Destination
OSH · Oshkosh, WI
Airport
7V6 · Camp Guernsey, runway 14, 5,500 × 75 ft, asphalt

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
39
Injuries
Serious
Certificate
Private
Airplane ratings
Single-engine land
Instrument ratings
Airplane
Medical
Class 2, Valid Medical--w/ waivers/lim
Last flight review
February 14, 2004
Seat
Left
Flight hours
425 total · 100 in this make and model · 350 as pilot in command · 50 in the last 90 days · 25 in the last 30 days · 6 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
130° at 12 knots
Visibility
10 statute miles
Lowest ceiling
3,300 ft broken
Temperature
64 °F, dew point 54 °F
Altimeter
30.34 inHg
Observed at
TOR, 28 nm away