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ASN Wikibase Occurrence # 44514
Last updated: 29 June 2020
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Type:Silhouette image of generic C170 model; specific model in this crash may look slightly different
Cessna 170B
Registration: N6352Y
C/n / msn: 25326
Fatalities:Fatalities: 1 / Occupants: 1
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:Portland, OR -   United States of America
Phase: En route
Departure airport:Pullman, WA (PUW)
Destination airport:Vancouver, WA (VUO)
Investigating agency: NTSB
The airplane was returning to its home airport when the pilot became incapacitated by carbon monoxide fumes from the airplanes engine muffler heat exchanger [the heat control knob was found "On"]. During the last 15 minutes of flight, the radar data shows the airplane flying several meandering 360 degree turns before impacting terrain. Postimpact examination of the engine's muffler revealed a crack around the entire circumference just aft of it's forward flange. The airplane's last annual inspection was completed on February 1, 2005. The FAA, in Federal Aviation Regulation, Part 43: Maintenance, Preventive maintenance, Rebuilding, and Alteration, Appendix D, provides guidelines for an airplane's annual inspection. Section (d) (8) Exhaust stacks--for cracks, defects, and improper attachment. The airplane's manufacturer also provides a checklist for an annual inspection in the aircraft's Service Manual. In the section for the Engine Compartment, #12. Exhaust system for security, leaks, cracks, and burned-out spots. Refer to Paragraph 12-74 [Inspection of the exhaust system].

Probable Cause: The pilot's inability to control the airplane due to his incapacitation (carbon monoxide poisoning) from a deteriorated engine exhaust muffler. A contributing factor was the inadequate annual inspection by other maintenance personnel.



Revision history:

28-Oct-2008 00:45 ASN archive Added
21-Dec-2016 19:24 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
06-Dec-2017 08:08 ASN Update Bot Updated [Source, Narrative]

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