Aniak Airport
Aircraft Accident/Incident Report

Aniak, Alaska 99557
Monday, December 17, 2007 19:40 AST

NTSB Narrative Summary Released at Completion of Accident

The flight crew of a cargo airplane had previously loaded a cargo of carbon dioxide cylinders, and then flew to an intermediate airport for fuel. The cylinders had a screw type valve, and a threaded metal safety cap to protect the valve. During the takeoff run after refueling, the crew aborted the takeoff, and taxied back to the airport ramp after hearing a "hissing" sound from the cargo area. Once on the ramp, the captain shut off the engines, but the flight crew lost consciousness before they could exit the airplane. Since the crew filed an IFR flight plan that was not activated, air traffic control personnel contacted the freight office to inquire about the status of the airplane. A freight agent noticed the airplane sitting on the ramp. He opened the door of the airplane, and found the first officer unconscious, inside the door. The captain was unconscious at the controls. He pulled both crewmembers out of the airplane, and ran for help. The flight crew regained consciousness while lying on the ramp, and walked to the freight building. The flight crew were treated at a hospital and released the following day. The first officer reported that as the captain was taxiing back to the airport ramp, he felt the effects of the gas release, and he and the captain opened the cockpit windows. Once stopped, he got up to open the forward door, but collapsed at the door. An FAA inspector examined the airplane, and discovered that the cargo compartment had two tank racks containing five bottles each, standing vertically along each side of the airplane. Two of the cylinders in the left side rack did not have any safety caps installed. Three of the cylinders in the right side rack also did not have any safety caps installed. The caps were found on the floor of the airplane. The inspector found that the middle tank of the three in the right side rack, had a partially open valve. The open tank valve was about 1/2 turn open, and was positioned against the interior side-wall of the cargo compartment. The FAA inspector also indicated that nine carbon dioxide tanks were lying on the floor of the cargo area. They were braced by chocks, but were not strapped down. The crew oxygen masks were not utilized, and the crew oxygen supply tank was full. An FAA Hazardous Materials Division inspector reported that cylinders of carbon dioxide are considered hazardous material because they are pressurized in excess of 40 psi. The inspector noted that the shipper had a responsibility to properly identify and declare hazardous materials that they were shipping, the carrier had a responsibility to properly train airplane crewmembers to identify and accept hazardous materials, and the flight crew had a responsibility to properly secure hazardous materials during transport.

NTSB Probable Cause Narrative

A hazardous leak from carbon dioxide cylinders due to the failure of the flight crew to properly load and secure the cylinders, resulting in crew incapacitation. Factors contributing to the incident were improper hazardous materials procedures used by the shipper, and a failure of the operator to properly train the flight crew in hazardous materials procedures.

Event Information

Type of Event Incident
Event Date 12/17/2007
Event Day of the Week Monday
Time of Event 1940
Event Time Zone Atlantic Standard Time
Event City Aniak
Event State ALASKA
Event Country --
Zipcode of the event site 99557
Event Date Year 2007
Event Date Month 12
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 613454N
Event Location Longitude 1593235W
Event Location Airport Aniak
Event Location Nearest Airport ID PANI
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation 88
Weather Briefing Completeness --
Investigator's weather source Pilot
Time of the weather observation
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID --
Elevation of weather observation facility --
Distance of event from weather observation facility (units?) --
Time Zone of the weather observation --
Lighting Conditions Night/Dark
Lowest Ceiling Height --
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) -21
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) --
Variable Wind Indicator Variable
Wind Speed (knots) --
Wind Velocity Indicator Light and Variable
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor 1
Injury Total None 1
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 23962
NTSB Notification Source FAA Regional Operations Center
NTSB Notification Date Dec 17 2007 12:00AM
NTSB Notification Time --
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Jul 30 2008 9:00AM
User who most recently changed record NTSB\johb
Basic weather conditions Visual Meteorological Cond
FAA District Office FAA-AL-ANC FSDO 03

Aircraft Involved

Aircraft #1

Aircraft Registration Number N111AX
NTSB Number ANC08IA026
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 135: Air Taxi & Commuter
Type of Flight Plan filed IFR
Flight plan Was Activated? No
Damage None
Aircraft Fire --
Aircraft Explosion --
Aircraft Manufacturer's Full Name Beech
Aircraft Model 1900
Aircraft Series Identifier --
Aircraft Serial Number UC-81
Certified Max Gross Weight 17600
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 3
Number of Engines 2
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Continuous Airworthiness
Date of Last Inspection Dec 1 2007 12:00AM
Airframe hours since last inspection 96
Airframe Hours 48506
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name Alaska Central Express
Aircraft Owner Street Address 5901 Lockheed Ave.
Aircraft Owner City Anchorage
Aircraft Owner State AK
Aircraft Owner Country USA
Aircraft Owner Zipcode 99502
Operator is an individual? No
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 YADA
Owner has at least one certificate --
Other Operator of large aircraft? --
Certified for Part 133 or 137 Operation --
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 Cargo
Type of Flying (Per_Bus / Primary) --
Second Pilot on Board Yes
Departure Point Same as Event Yes
Departure Airport Code PANI
Departure City Aniak
Departure State AK
Departure Country USA
Departure Time 1940
Departure Time Zone AST
Destination Same as Local Flt --
Destination Airport Code PANC
Destination City Anchorage
Destination State AK
Destination Country USA
Specific Phase of Flight Takeoff - roll/run
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jul 16 2008 7:35PM
User who most recently changed record STAM
Since inspection or accident Time of Accident
Event Location Runway Number and Location NA
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --