Aircraft Accident/Incident Report

Skwentna, Alaska 99667
Saturday, July 5, 1997 9:30 AKD

NTSB Narrative Summary Released at Completion of Accident

The pilot boarded the 4 passengers and cargo (unsecured) for a chartered flight to a fishing lodge. The floatplane departed uneventfully. About 45 min. later, while cruising about 1,700 ft. above rugged terrain and a river, the engine began to lose power and the floatplane descended. The pilot attempted a forced landing in a small lake that was 1,200 ft. in length and located about 1 mile west of the river. During the approach to landing, the airplane stalled and impacted swampy terrain at the lake's edge in a steep nose down attitude. An examination of the wreckage revealed that the no.1 engine exhaust pushrod had failed in fatigue just below the top (valve) ball end. Examination of the pushrod revealed that material had been pushed away from the rod during installation of the ball end. The fatigue crack may have initiated from a score mark produced by the installation. Pushrod life is reduced due to surface scratches. The life of the failed pushrod could not be determined. Insufficient information exists in the overhaul manual regarding pushrod life/inspection.

NTSB Probable Cause Narrative

a loss of engine power due to the fatigue failure of the no.1 exhaust push rod. Factors contributing to the accident were: insufficient information on pushrod inspection and overhaul from the manufacturer, unsuitable terrain available for landing, and the pilot's failure to maintain airspeed during the approach which led to an inadvertent stall.

Event Information

Type of Event Accident
Event Date 7/5/1997
Event Day of the Week Saturday
Time of Event 930
Event Time Zone --
Event City SKWENTNA
Event State ALASKA
Event Country --
Zipcode of the event site 99667
Event Date Year 1997
Event Date Month 7
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport
Event Location Nearest Airport ID
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 853 Atlantic Daylight Time
Direction of event from weather observation facility (degrees) 224
Weather Observation Facility ID SKW
Elevation of weather observation facility 0
Distance of event from weather observation facility (units?) 8
Time Zone of the weather observation ADT
Lighting Conditions Day
Lowest Ceiling Height 1500
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Unknown
Sky Condition for Lowest Ceiling Broken
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 15
Air Temperature at event time (in degrees celsius) 13
Dew Point at event time (in degress fahrenheit) 11
Wind Direction (degrees magnetic) 155
Variable Wind Indicator Unknown
Wind Speed (knots) 5
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Fatal
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal 4
Injury Total Minor --
Injury Total None --
Injury Total Serious 1
Injury Total All 5
Investigating Agency NTSB
NTSB Docket Number (internal use) 1524
NTSB Notification Source --
NTSB Notification Date --
NTSB Notification Time 0
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 18 2002 11:28AM
User who most recently changed record NTSB\GIUV
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N5164G
NTSB Number ANC97FA099
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 135: Air Taxi & Commuter
Type of Flight Plan filed Company VFR
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name de Havilland
Aircraft Model DHC-2
Aircraft Series Identifier DHC-2
Aircraft Serial Number 506
Certified Max Gross Weight 5090
Aircraft Category Airplane
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 5
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection Jun 26 1997 12:00AM
Airframe hours since last inspection 24
Airframe Hours 13864
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name ALASKA BUSH CARRIERS, INC.
Aircraft Owner Street Address 4501 AIRCRAFT DRIVE
Aircraft Owner City ANCHORAGE
Aircraft Owner State AK
Aircraft Owner Country
Aircraft Owner Zipcode 99502
Operator is an individual? --
Operator Name
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address
Operator City
Operator State
Operator Country
Operator Zip code
Operator Code EMHA
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Non-scheduled
Indicates Domestic or International Flight Domestic
Operator carrying Pax/Cargo/Mail Passenger/Cargo
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code
Departure City LAKE HOOD
Departure State AK
Departure Country
Departure Time 840
Departure Time Zone ADT
Destination Same as Local Flt --
Destination Airport Code
Destination City CHELATNA LAKE
Destination State AK
Destination Country
Specific Phase of Flight Cruise
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:34AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --