ANC01LA050

NTSB accident investigation · Stinson 108-3 · Glennallen, AK · April 22, 2001

Accident · Minor injuriesLimited investigationFinal report
Date
April 21, 2001, 18:00 local (Apr 22, 2001, 02:00 UTC)
Place
Glennallen, AK
Injuries
1 minor
Damage
Destroyed
Phase of flight
Enroute
Aircraft
N6912MStinson 108-3
Weather
Visual (VMC) · Day
Status
Completed · report October 2, 2001
Report
Approved by Office Director
NTSB office
Alaska Regional Office
Parties
FAA-AL-ANC FSDO 01
FAA report
20010421039919A
Case key
53190

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

A total failure of the engine and subsequent rupture of the crankcase during cruise flight. A factor in the accident was unsuitable 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 power(total) - mech failure/malfCruise
Engine assembly - failureCause
Engine assembly,crankcase - rupturedCause
Forced landingEmergency descent/landing
In flight collision with terrain/waterEmergency descent/landing
Terrain condition - none suitableFactor

Analysis

The pilot, holder of a student pilot certificate, was on a cross-country personal flight over remote terrain. While in cruise flight, the engine suddenly began producing a heavy vibration. It also began to smoke and produce oil on the windshield, and then the propeller stopped. The airplane began to descend and the pilot turned toward a small frozen lake, located about 5 miles from a major highway. The area around the lake was surrounded by tall trees. The pilot selected a forced landing area between several trees in an area only large enough to fit the main fuselage. During the collision, the windshield was broken out, the cabin doors were torn off, and the wings were extensively damage, including rupturing of the wing fuel tanks. The cockpit area remain intact and the pilot exited the airplane with a small backpack. A postcrash fire then erupted and the airplane was consumed. The flight was not reported overdue, and no emergency locator transmitter (ELT) signals were detected by search and rescue personnel. The following day, the pilot said he used a handheld radio to contact an airplane flying over the area and requested assistance. The pilot of the other airplane landed on the small frozen lake and picked up the pilot. Following the accident, the pilot reported that internal components of the engine failed and ruptured the engine case.

Factual narrative

On April 21, 2001, about 1800 Alaska daylight time, a tundra tire equipped Stinson 108-3 airplane, N6912M, was destroyed by impact and a postimpact fire after colliding with trees during a forced landing, about 27 miles southwest of Glennallen, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight when the accident occurred. The airplane was operated by the pilot. The pilot, holder of a student pilot certificate, received minor injuries. Visual meteorological conditions prevailed. A VFR flight plan was not filed. The flight originated at the Cordova Municipal Airport, Cordova, Alaska, about 1600.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on April 23, 2001, the pilot reported he was in cruise flight about 4,000 feet msl. The engine suddenly began producing a heavy vibration. It also began to smoke and produce oil on the windshield, and then the propeller stopped. The airplane began to descend and the pilot turned toward a small frozen lake, located about 5 miles from a major highway. The area around the lake was surrounded by tall trees. The pilot selected a forced landing area between several trees in an area only large enough to fit the main fuselage. During the collision, the windshield was broken out, the cabin doors were torn off, and the wings were extensively damaged, including rupturing of the wing fuel tanks. The cockpit area remained intact and the pilot exited the airplane with a small backpack. A postcrash fire then erupted and the airplane was consumed.

The flight was not reported overdue, and no emergency locator transmitter (ELT) signals were detected by search and rescue personnel. The following day, the pilot said he used a handheld radio to contact an airplane flying over the area and requested assistance. The pilot of the other airplane landed on the small frozen lake and picked up the pilot.

The pilot holds a student pilot certificate, and has about 1,000 hours of flight time. The pilot reported the engine had accrued 1,060.13 hours since a major overhaul. Following the accident, portions of the airplane and engine were removed from the crash scene. On August 23, 2001, the pilot reported to the NTSB IIC that internal components of the engine failed and ruptured the engine case.

Aircraft

Registration
N6912M
Reported as
Stinson 108-3
Category
Airplane
Serial number
108-4912
Airframe hours
2,882
Engine
Continental O-470-K, 230 horsepower, reciprocating
Damage
Destroyed
Fire
On-Ground
Flight
Personal · Part 91
Airworthiness certificate
Standard, Normal
Last inspection
Annual · February 9, 2001 · 19 hours before
Departed
CKU · Cordova, AK
Destination
BGQ · Big Lake, AK

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
36
Injuries
Minor
Certificate
Student
Medical
Class 3, Valid Medical--w/ waivers/lim
Last flight review
March 11, 2000
Seat
Left
Flight hours
1,000 total

Weather

Conditions
Visual (VMC) · Day
Wind
100° at 5 knots
Visibility
40 statute miles
Lowest ceiling
8,000 ft broken
Temperature
45 °F

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.