Aircraft Accident/Incident Report

King Salmon, Alaska 99613
Tuesady, September 24, 1996 10:15 AKD

NTSB Narrative Summary Released at Completion of Accident

The pilot and three passengers were departing a remote lake in a float equipped airplane. The pilot positioned the hydraulic actuated flaps to 20 degrees. After takeoff, about 150 ft above the water, the pilot positioned the flap lever to the 'UP' position in preparation of pumping the flaps up, but said he did not move the pump handle. Turbulence was present during the takeoff, and during a left turn, the pilot encountered a severe gust at the time he positioned the flap lever. The airplane stalled in a left turn that steepened to almost a 90 degree bank. The airplane descended and the left wing contacted the surface of the lake. The left wing was torn off the fuselage, and the floats were crushed upward. Both flaps are activated by a common torque tube connected to a double-acting flap actuating cylinder. At the accident scene, the right wing flap and right aileron were observed to be extended to an intermediate position. The weather conditions included 20 kts of wind, turbulence, and rain. The pilot expressed a concern that the flaps may have retracted without being pumped to the up position. An examination of the flap system and the ratchet valve assembly was conducted after the airplane was recovered and the wings were removed. Leakage of hydraulic fluid and air was observed through the ratchet valve. Additional testing of the ratchet valve at an overhaul facility did not reveal any leakage.

NTSB Probable Cause Narrative

failure of the pilot to maintain sufficient airspeed during the initial climb after takeoff, which resulted in an inadvertent stall and collision with the terrain (water). Turbulence was a related factor.

Event Information

Type of Event Accident
Event Date 9/24/1996
Event Day of the Week Tuesday
Time of Event 1015
Event Time Zone --
Event City KING SALMON
Event State ALASKA
Event Country --
Zipcode of the event site 99613
Event Date Year 1996
Event Date Month 9
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 Witness
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 Day
Lowest Ceiling Height 2500
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Unknown
Sky Condition for Lowest Ceiling Overcast
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) 4
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 70
Variable Wind Indicator Unknown
Wind Speed (knots) 20
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 Light
METAR weather report --
Event Highest Injury Serious
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor 2
Injury Total None --
Injury Total Serious 2
Injury Total All 4
Investigating Agency NTSB
NTSB Docket Number (internal use) 1880
NTSB Notification Source --
NTSB Notification Date Sep 24 1996 12:00AM
NTSB Notification Time 1300
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 10:21AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N67207
NTSB Number ANC96TA163
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
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 U-6A
Aircraft Series Identifier U-6A
Aircraft Serial Number 305
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 8
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection Sep 5 1996 12:00AM
Airframe hours since last inspection 75
Airframe Hours 10869
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name HARTLEY INC.
Aircraft Owner Street Address P.O. BOX 545
Aircraft Owner City KING SALMON
Aircraft Owner State AK
Aircraft Owner Country
Aircraft Owner Zipcode 99613
Operator is an individual? --
Operator Name U.S. GOVT. DEPT OF INTERIOR
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address 2350 W. ROBINSON RD.
Operator City BOISE
Operator State ID
Operator Country
Operator Zip code 83705
Operator Code
Owner has at least one certificate None
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 --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code
Departure City BROOKS CAMP
Departure State AK
Departure Country
Departure Time 1015
Departure Time Zone ADT
Destination Same as Local Flt crash at destination city
Destination Airport Code AKN
Destination City
Destination State AK
Destination Country
Specific Phase of Flight Takeoff
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 --