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Last updated: 26 November 2021
Status:Definitief
Datum:woensdag 19 december 1984
Tijd:11:08
Type:Silhouette image of generic DH3T model; specific model in this crash may look slightly different
de Havilland Canada DHC-3T Cox Turbine Otter
Luchtvaartmaatschappij:Cox Aircraft Corp.
Registratie: N4247A
Constructienummer: 421
Bouwjaar: 1964
Aantal vlieguren:7445
Motoren: 1 Pratt & Whitney Canada PT6A-135
Bemanning:slachtoffers: 0 / inzittenden: 1
Passagiers:slachtoffers: 0 / inzittenden: 2
Totaal:slachtoffers: 0 / inzittenden: 3
Schade: Groot
Gevolgen: Written off (damaged beyond repair)
Plaats:Alki Point, Seattle, WA (   Verenigde Staten)
Fase: Kruisvlucht (ENR)
Soort vlucht:Test
Vliegveld van vertrek:Seattle-Boeing Field International Airport, WA (BFI/KBFI), Verenigde Staten
Vliegveld van aankomst:Seattle-Boeing Field International Airport, WA (BFI/KBFI), Verenigde Staten
Beschrijving:
The re-engined turboprop Otter was performing a test flight maneuvers when problems with the modified fuel system occurred. Ice blocking a fuel vent line caused a partial collapse of the main (engine feed) fuel cell which produced an erroneous fuel quantity reading. In addition, the main tank overflow shutoff valve was leaking, so tank overflow occurred. The fuel overflow caution light illuminated and auxiliary tank fuel pump feed to main automatically shut down. Due to miscalibration, this system overrode pilot attempts to restart aux fuel pumps. The pilot remained in test area troubleshooting rather than an immediate return to base. He finally noted main tank gauge continued to read 'full.' En route to Boeing Field, fuel starvation occurred. He attempted a forced landing in a small athletic field in a residential area rather than ditch in Puget Sound. The aircraft touched down, then bounced across an adjacent street. The arresting action of telephone wires on the vertical fin brought the aircraft to rest in a residential backyard.

Probable Cause:

PROBABLE CAUSE:
fuel system,vent..blocked(total)
fluid,fuel..starvation
CONTRIBUTING FACTORS:
precautionary landing..delayed..pilot in command
terrain condition..none suitable
fuel supply..misjudged..pilot in command
fuel system,tank..distorted
engine instruments,fuel quantity gage..false indication
fuel system,fuel shutoff..leak

Bronnen:
» NTSB


Foto's

photo of DHC-3T-Cox-Turbine-Otter-N4247A
accident date: 19-12-1984
type: de Havilland Canada DHC-3T Cox Turbine Otter
registration: N4247A
photo of DHC-3T-Cox-Turbine-Otter-N4247A
accident date: 19-12-1984
type: de Havilland Canada DHC-3T Cox Turbine Otter
registration: N4247A
photo of DHC-3T-Cox-Turbine-Otter-N4247A
accident date: 19-12-1984
type: de Havilland Canada DHC-3T Cox Turbine Otter
registration: N4247A
photo of DHC-3T-Cox-Turbine-Otter-N4247A
accident date: 19-12-1984
type: de Havilland Canada DHC-3T Cox Turbine Otter
registration: N4247A
 

Kaart

This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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