Akiachak, AK, USA
N8466Y
PIPER PA-18-150
The private pilot departed on a flight between two remote Alaskan communities; however, because of deteriorating weather conditions along the flight route, he decided to return to his home airport. During the return flight, the pilot became concerned about his remaining fuel and diverted to an alternate airport. When he reached that airport, he elected not to land because he believed that he had enough fuel to reach his home airport. As the flight continued, the engine lost power, but the pilot was able to switch fuel tanks and restart the engine. While maneuvering to land at the closest airport, all engine power was lost, and the pilot selected an off-airport, snow-and tree-covered area for a forced landing. He said that during the approach, the airplane stalled and collided with terrain. The airplane sustained substantial damage to the wings, lift struts, and fuselage. The pilot also reported that while en route to the alternate airport, the instrument panel-mounted carbon monoxide detector turned black. According to the carbon monoxide detector manufacturer, a positive indication for carbon monoxide would be indicated by the detector showing yellow, green, or dark blue color. Any other color would indicate that the detector was contaminated or outdated. No expiration date was recorded on the accident airplane's carbon monoxide detector. A postaccident examination of the airplane’s muffler and cabin heater muff did not disclose any leaks or mechanical anomalies. Therefore, it is unlikely that there was a problem with carbon monoxide during the flight. The pilot indicated that there were no preaccident mechanical problems with the airplane that would have precluded normal operation and noted that the loss of engine power was due to fuel exhaustion.
On November 11, 2012, about 1700 Alaska standard time, a Piper PA-18-150 airplane, N8466Y, sustained substantial damage during a forced landing, following a loss of engine power, near Akiachak, Alaska. The airplane was being operated by the pilot as a visual flight rules (VFR) cross-country flight under the provisions of Title 14, CFR Part 91, when the accident occurred. The certificated private pilot, the sole occupant of the airplane, sustained minor injuries. Marginal visual meteorological conditions prevailed, and no flight plan had been filed. The flight departed Aniak, Alaska, about 1600, en route to Bethel, Alaska. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on November 11, the pilot stated that he ran out of fuel. He explained that he had attempted to fly from Bethel to Willow, Alaska earlier in the day, but had turned around due to deteriorating weather conditions along the route, and at the time of the accident he was attempting to return to Bethel. He said he stopped briefly in Aniak, and departed with approximately 9 gallons of fuel on board for the 82 nautical mile flight to Bethel. While en route he became concerned about fuel duration, and diverted to Tuluksak, Alaska, which he then overflew having determined that he had sufficient fuel to reach Bethel, which was 32.1 nautical miles southwest. The pilot said he had exhausted all the fuel out of the right fuel tank and when the engine lost power, he switched the fuel selector to the left fuel tank, and the engine continued to run. The pilot reported that while maneuvering to land at the Akiachak Airport, which was the closest airport, all engine power was lost, and he selected an off-airport, snow and tree-covered area as a forced landing site. He said that during the approach, the airplane stalled and collided with terrain. The airplane sustained substantial damage to the wings, lift struts, and fuselage. The pilot also reported that near Tuluksak, approximately 58 miles Southwest of Aniak, he noticed the airplanes carbon monoxide detector had turned black. During a telephone conversation with the NTSB IIC on November 12, an Alaskan State Trooper reported he was in his office when he observed the accident airplane land in Aniak. He walked out to see if the pilot needed assistance, and noted ice on the airframe. He said they had a brief discussion about how to de-ice the airplane and where to purchase fuel. The trooper then returned to his office and shortly thereafter was surprised to hear the accident airplane depart. He stated the pilot would not have had sufficient time to de-ice or fuel the airplane before his departure. On December 3, 2012 the pilot reported that both he and the Akiachak Village Police Officer (VPO) who had located the carbon monoxide detector at the accident site on November 16, recalled that the detector had turned black. On December 11, 2012, about 1 month after the accident, the pilot reported that he experienced an elevated heart rate, and severe headache following the accident. Prior to the accident he reported impaired judgment and confusion. The Federal Aviation Administration (FAA), Advisory Circular AC 20-32B – Carbon Monoxide Contamination in Aircraft – Detection and Prevention states in part: Early symptoms of CO poisoning are feelings of sluggishness, being too warm, and tightness across the forehead. The early symptoms may be followed by more intense feelings such as headache, throbbing or pressure in the temples, and ringing in the ears. These in turn may be followed by severe headache, general weakness, dizziness, and gradual dimming of vision. Large accumulations of CO in the body result in loss of muscular power, vomiting, convulsions, and coma. Finally, there is a gradual weakening of the pulse, a slowing of the respiratory rate, and death. In the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1) submitted by the pilot, he indicated that there were no preaccident mechanical anomalies with the airplane. Additionally, he stated that 24 hours after the accident he had a carboxyhemoglobin (COHb) level of 1.3%, and attributed this to possible carbon monoxide poisoning. The US Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry, ToxGuide for Carbon Monoxide states typical COHb levels in non-smokers to be 0.5 – 1.5%. On December 28, 2012 a Federal Aviation Administration (FAA) aviation safety inspector from the Anchorage Flight Standards District Office (FSDO), disassembled and inspected the muffler assembly from the accident airplane, and no leaks or anomalies were found. The airplane was equipped with an AERO Phoenix Aviation Distributors 18 month carbon monoxide detector manufactured by Quantum Eye. The Quantum Eye is a multi-level carbon monoxide detector providing a visual indication of carbon monoxide contamination. If carbon monoxide is present the sensor changes color, yellow = normal, green = caution, and dark blue = danger. The Quantum Eye instruction manual states in part: "The Quantum Eye® has an 18-month product life once it has been activated. Excessive dosages, multiple exposures, or use after the expiration date may cause the sensor to turn permanently dark. If the sensor turns any color other than those shown, it has been contaminated and must be replaced. Keep the sensor away from water, grease, solvents, dirt, hot surfaces, cleaning solutions, and other contaminants, which may destroy or shorten the life of the sensor." An area is provided to record the required replacement date on the face of the detector 18-months after installation, but no date was recorded on the accident airplane’s carbon monoxide detector. The closest weather reporting facility is Bethel Airport, approximately 17 miles southwest of the accident site. About 7 minutes before the accident, at 1653, an aviation routine weather report (METAR) at Bethel Airport, Bethel, Alaska, reported in part: wind from 020 degrees, at 6 knots, visibility, 9 statute miles; mist; overcast clouds at 600 feet, temperature, 22 degrees F; dew point 21, degrees F; altimeter, 29.93 inHG.
The pilot's inadequate fuel planning, which resulted in a loss of engine power due to fuel exhaustion, and the pilot’s failure to maintain adequate airspeed during the subsequent forced landing, which resulted in an inadvertent stall.
Source: NTSB Aviation Accident Database
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