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ASN Wikibase Occurrence # 44952
Last updated: 17 January 2020
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Type:Silhouette image of generic C172 model; specific model in this crash may look slightly different
Cessna 172K
Registration: N99LR
C/n / msn: 17259099
Fatalities:Fatalities: 2 / Occupants: 2
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:Grass Valley, CA -   United States of America
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Departure airport:Grass Valley, CA (O17)
Destination airport:Palo Alto, CA (PAO)
Investigating agency: NTSB
The airplane collided with trees while attempting to land in IFR conditions of near zero visibility in fog. While en route to the destination airport on an IFR clearance, the TRACON controller observed the airplane's transponder discrete code change to 7600 (used by flight crews to indicate a communications failure). The TRACON controller determined that the pilot could hear them, but they could not hear his transmissions. Because of the requirement for full communications in controlled, Class B airspace, they suggested the pilot contact a nearby airport outside of the Class B airspace on the frequency they provided. The pilot contacted the suggested ATCT while 12 miles west of that airport, and the controller could barely hear the pilot's transmissions. The pilot advised the tower to cancel his IFR flight plan and he would proceed visual flight rules (VFR) back to his departure airport without VFR flight following. This was the last communication from the pilot. Witnesses heard the pilot make two approach attempts to land at original departure airport but they could not see the airplane because the airport had become zero visibility and zero ceiling in fog about 20 minutes prior to the airplanes arrival.
Probable Cause: the pilot's continued visual flight into instrument meteorological conditions and failure to maintain an adequate terrain/object clearance altitude. Also causal was the pilot's improper in-flight decision to return to the origin airport in the face of deteriorating weather conditions instead of diverting to a more suitable alternate.



Revision history:

28-Oct-2008 00:45 ASN archive Added
21-Dec-2016 19:24 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
07-Dec-2017 17:36 ASN Update Bot Updated [Destination airport, Source, Narrative]

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