Aircraft Accident/Incident Report

Iliamna, Alaska 99606
Wednesday, August 25, 1999 6:20 AKD

NTSB Narrative Summary Released at Completion of Accident

The certificated commercial pilot was attempting to takeoff from a lake with 2 feet tall, rolling swells. The pilot said that during the takeoff run, before a safe flying airspeed was attained, the airplane floats struck a large wave, and the airplane lifted off the water prematurely. He said that before he could react, the left wing stalled, and the airplane collided with the water. During the collision, the floats were torn off the airplane, and the airplane sank. The airplane sustained substantial damage to the fuselage, empennage, and wings. The closest official weather observation station is Iliamna. On August 25, 1999, at 0553, an Aviation Routine Weather Report (METAR) was reporting in part: Wind, 259 degrees (magnetic) at 7 knots; visibility, 10 statute miles; clouds, 7,500 feet broken; temperature, 51 degrees F; dew point, 46 degrees F; altimeter, 29.52 inHg. Official civil twilight for Iliamna was at 0610.

NTSB Probable Cause Narrative

The pilot's selection of an unsuitable takeoff area, and an inadvertent stall. Factors associated with the accident were large wave/swells, and low light conditions (dawn).

Event Information

Type of Event Accident
Event Date 8/25/1999
Event Day of the Week Wednesday
Time of Event 620
Event Time Zone --
Event City ILIAMNA
Event State ALASKA
Event Country --
Zipcode of the event site 99606
Event Date Year 1999
Event Date Month 8
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 Pilot
Time of the weather observation 0
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID
Elevation of weather observation facility 0
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation
Lighting Conditions Dawn
Lowest Ceiling Height 7500
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) 10
Air Temperature at event time (in degrees celsius) 10
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 259
Variable Wind Indicator Unknown
Wind Speed (knots) 7
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None 5
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 710
NTSB Notification Source --
NTSB Notification Date Aug 25 1999 12:00AM
NTSB Notification Time 745
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Jan 10 2001 9:43AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N930TG
NTSB Number ANC99LA124
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 1041
Certified Max Gross Weight 5100
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 6
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Aug 20 1999 12:00AM
Airframe hours since last inspection 5
Airframe Hours 15661
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name ARTHUR E. GERKEN
Aircraft Owner Street Address P.O. BOX 228
Aircraft Owner City ILIAMNA
Aircraft Owner State AK
Aircraft Owner Country
Aircraft Owner Zipcode 99606
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 T8GC
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 Only
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code ILI
Departure City
Departure State AK
Departure Country
Departure Time 620
Departure Time Zone ADT
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code
Destination City
Destination State
Destination Country
Specific Phase of Flight Takeoff
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 10 2001 12:27PM
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 --