ANC99LA082

NTSB accident investigation · Maule M-4-220C · Mcgrath, AK · June 24, 1999

Accident · No injuriesLimited investigationFinal report
Date
June 24, 1999, 12:20 local (20:20 UTC)
Place
Mcgrath, AK
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N40677Maule M-4-220C
Weather
Visual (VMC) · Day
Status
Completed · report June 23, 2000
Report
Approved by Office Director
NTSB office
Alaska Regional Office
FAA report
19990624007559A
Case key
46654

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 separation of the number 4 engine cylinder, and a fracture of the number 4 engine connecting rod.

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(partial) - mech failure/malfCruise
Engine assembly,cylinder - separationCause
Engine assembly,connecting rod - fracturedCause
On ground/water collision with objectLanding - roll
Object - tree(s)
Main gear collapsedLanding - roll

Analysis

The airline transport pilot reported that about 15 minutes after departure, the engine began to run rough, and lose power. He said that while performing the engine emergency procedures, he smelled smoke in the cabin, and he selected a forced landing area on a river bank bordered by trees. During the landing roll, the airplane's left wing collided with a stand of trees, the airplane pivoted 180 degrees to the left, and the left main landing gear collapsed. The airplane sustained substantial damage to the wings, fuselage, and empennage. An FAA airworthiness inspector from the Anchorage Flight Standards District Office, examined the airplane wreckage on June 24th. The inspector reported that the top portion of the number four engine cylinder was separated between the cylinder barrel and the cylinder head, and added that the piston connecting rod was fractured.

Factual narrative

On June 24, 1999, about 1220 Alaska daylight time, a wheel equipped Maule M-4-220C airplane, N40677, sustained substantial damage during a forced landing about 7 miles northeast of McGrath, Alaska. The airplane was being operated as a visual flight rules (VFR) personal flight when the accident occurred. The solo airline transport pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed. The flight was the continuation of a cross-country flight that originated at the Willow Airport, Willow, Alaska, about 0930.

During a telephone conversation with the National Transportation Safety Board investigator-in-charge on June 24, the pilot reported that his planned destination was Nikolai, Alaska, with a brief stop in Takotna, Alaska. He said that the flight between Willow and Takotna was uneventful. The pilot reported that after takeoff from the Takotna Airport, he climbed the airplane to about 1,500 feet msl. He said that about 15 minutes after departure, the engine began to run rough, and lose power. The pilot said that while performing the engine emergency procedures, he smelled smoke in the cabin, and selected a forced landing area on a river bank bordered by trees. During the landing roll, the airplane's left wing collided with a stand of trees, the airplane pivoted 180 degrees to the left, and the left main landing gear collapsed.

The airplane sustained substantial damage to the wings, fuselage, and empennage.

The airplane owner recovered and transported the airplane wreckage to the Anchorage International Airport. A Federal Aviation Administration (FAA) airworthiness inspector from the Anchorage Flight Standards District Office, examined the airplane wreckage on July 13th. The inspector reported that the top portion of the number four engine cylinder was separated between the cylinder barrel and the cylinder head, and added that the piston connecting rod was fractured.

Aircraft

Registration
N40677
Reported as
Maule M-4-220C
Category
Airplane
Serial number
2181C
Airframe hours
2,370
Engine
Franklin 6A-350-C1, 220 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Operator
Walt Warner
Registered owner
Bonnie L. Warner
Airworthiness certificate
Standard, Normal
Last inspection
Annual · August 31, 1998 · 160 hours before
Departed
UUO · Willow, AK
Destination
MCG · 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
44
Certificates
Flight instructor, Airline transport
Airplane ratings
Multi-engine land, Single-engine sea, Single-engine land
Instrument ratings
Airplane
Medical
Class 2, Valid Medical--no waivers/lim.
Seat
Left
Flight hours
8,500 total · 1,100 in this make and model · 90 in the last 90 days · 30 in the last 30 days · 2 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
350° at 5 knots
Visibility
10 statute miles
Lowest ceiling
7,000 ft broken
Temperature
68 °F, dew point 54 °F
Altimeter
29.00 inHg
Observed at
MCG, 7 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.