Aircraft Accident/Incident Report

Mcgrath, Alaska 99627
Thursday, August 12, 2010 15:00 AKD

NTSB Narrative Summary Released at Completion of Accident

The pilot and passenger were in the first in a flight of two airplanes operating as a personal cross-country flight. As the flight progressed, both airplanes descended due to deteriorating weather conditions as they passed over an area of steep mountainous terrain. The second pilot said that visibility deteriorated to a point that it was difficult to discern topographical features. He then lost sight of the first airplane, so he elected to turn around. No further radio communications were received from the accident airplane. The airplane’s wreckage was subsequently found in an area of mountainous terrain, along the anticipated flight path, at the end of a box canyon. During the on-scene examination of the wreckage, no preaccident mechanical anomalies were discovered. Given the lack of mechanical anomalies, the reported weather conditions, and the statement of the pilot of the second airplane, it is likely that the pilot of the accident airplane flew into instrument meteorological conditions while trying to maneuver the airplane through mountainous terrain. Additionally, given the impact signatures, it’s likely that the pilot was attempting to avoid rising terrain by climbing the airplane, which resulted in an aerodynamic stall.

NTSB Probable Cause Narrative

The pilot’s continued visual flight into instrument meteorological conditions and the airplane’s subsequent aerodynamic stall, which resulted in an in-flight collision with mountainous terrain.

Event Information

Type of Event Accident
Event Date 8/12/2010
Event Day of the Week Thursday
Time of Event 1500
Event Time Zone --
Event City McGrath
Event State ALASKA
Event Country --
Zipcode of the event site 99627
Event Date Year 2010
Event Date Month 8
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 632946N
Event Location Longitude 1545455W
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 --
Investigator's weather source Weather Observation Facility
Time of the weather observation 1456 Atlantic Daylight Time
Direction of event from weather observation facility (degrees) 135
Weather Observation Facility ID PAFS
Elevation of weather observation facility --
Distance of event from weather observation facility (units?) 32
Time Zone of the weather observation ADT
Lighting Conditions Day
Lowest Ceiling Height 1100
Lowest Non-Ceiling Height 500
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling Broken
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 5
Air Temperature at event time (in degrees celsius) 11
Dew Point at event time (in degress fahrenheit) 9
Wind Direction (degrees magnetic) 210
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 3
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30.18
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report METAR PAFS 122256Z AUTO 21003KT 5SM -RA BR SCT005
Event Highest Injury Fatal
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal 2
Injury Total Minor --
Injury Total None --
Injury Total Serious --
Injury Total All 2
Investigating Agency NTSB
NTSB Docket Number (internal use) 30356
NTSB Notification Source FAA ROC
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information --
Date of most recent change to record Sep 5 2012 1:34PM
User who most recently changed record stam
Basic weather conditions Instrument Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N2413H
NTSB Number ANC10FA069
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name PIPER
Aircraft Model PA-18-150
Aircraft Series Identifier --
Aircraft Serial Number 18-7909182
Certified Max Gross Weight --
Aircraft Category Airplane
Aircraft Registration Class --
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 2
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Unknown
Date of Last Inspection --
Airframe hours since last inspection --
Airframe Hours --
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site No
ELT Type Unknown
Aircraft Owner Name GRAYBILL DOLORES M
Aircraft Owner Street Address --
Aircraft Owner City CHUGIAK
Aircraft Owner State AK
Aircraft Owner Country USA
Aircraft Owner Zipcode 99567-0358
Operator is an individual? Yes
Operator Name GRAYBILL JOHN
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address --
Operator City CHUGIAK
Operator State AK
Operator Country USA
Operator Zip code 99567-0358
Operator Code --
Owner has at least one certificate None
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation --
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) Personal
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code PATA
Departure City Tanana
Departure State AK
Departure Country USA
Departure Time --
Departure Time Zone ADT
Destination Same as Local Flt --
Destination Airport Code PAMC
Destination City McGrath
Destination State AK
Destination Country USA
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Sep 5 2012 1:35PM
User who most recently changed record stam
Since inspection or accident --
Event Location Runway Number and Location N/A
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --