NTSB Identification: LAX05LA120.
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Accident occurred Tuesday, March 22, 2005 in Carefree, AZ
Probable Cause Approval Date: 02/28/2006
Aircraft: Cessna T210N, registration: N6897N
Injuries: 2 Serious,3 Minor.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The airplane hit the ground short of the runway following a failure of the engine to respond to throttle command on short final approach. The pilot said that on short final with the landing gear down and full flaps, the airplane started settling. The pilot added power and the engine failed to respond. The pilot said that it was his habit to use the low fuel boost pump for landing even though the Pilot Owner Handbook (POH) did not call for it. In the POH section 7, Airplane and System Descriptions, it shares an information note: "If the engine-driven fuel pump is functioning and the auxiliary fuel pump switch is placed in the ON position, an excessively rich fuel/air ratio is produced unless the mixture is leaned." With the low (yellow) boost pump switch on during a reduced power approach, if the throttle is increased the boost pump goes to high and the engine can be flooded with an excessive rich mixture. According to the Cessna Pilot Safety and Warning Supplements booklet under Fuel Pressure Switch Operation/Normal Auxiliary Fuel Pump Operation, it states in part: "During cruise, the auxiliary fuel pump(s) may be used at any time to clear excessive fuel vapor, as evidenced by an unstable fuel flow indication; however; the auxiliary fuel pump(s) should be turned off prior to descent. Failure to turn off the pump(s) could cause a power failure at reduced throttle settings or with a rapid throttle advance due to an excessively rich mixture, especially if the throttle switch rigging or fuel pressure switch settings are out of tolerance." No anomalies were found during an examination that would have precluded the engine from functioning normally.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: the pilot's improper use of the fuel boost pump contrary to the procedures specified in the pilot owner handbook and other documents. Full narrative available
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