Date: 201311
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: Rain; 6
Light: Night
Aircraft: PA-30 Twin Comanche
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Personal
Flight phase: Initial Approach
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: Fuel Selector
Component problem: Design; Improperly Operated
Reporter organization: Personal
Reporter function: Single Pilot; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Commercial; Flight Crew Flight Instructor
Human factors: Workload; Confusion
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Inflight Shutdown; Flight Crew Landed in Emergency Condition; General Declared Emergency
Contributing factors: Aircraft; Procedure
Primary problem: Aircraft

Narrative: While flying solo under an IFR flight plan in a rental Twin Comanche (PA30) approximately 20 nautical miles to the east of my destination; I was cleared to descend from 8;000 FT to 6;000 FT. At this time; I was in an IMC condition with light rain. As part of routine pre-landing checks; I switched both left and right tanks from auxiliary to main. As I was reaching 6;000 FT; the right engine started to run rough for a few seconds and subsequently failed. Since I was in the landing phase of the flight; there was no time to complete the so called 'cause check' procedure. When ATC asked me to maintain the altitude I responded 'Unable' and explained that I was on one engine only. At this time I was in a VMC; I squawked 7700 and declared emergency and requested vector to the nearest airport. ATC vectored me to a nearby airport and I acknowledge that the airport was in sight. ATC advised that I could land on any runway and switch to Tower frequency. Tower immediately cleared me to land; I maintained a safe airspeed; lowered the landing gear and flaps and landed on Runway 30L uneventfully and stopped on the runway short of Taxiway K and shut down the left engine as instructed by the Tower. I immediately notified the school flight instructor and owner and discussed the possibilities and agreed to defer a mechanic inspection until later and after I complete my own investigation. Next day in the morning; I found that although the fuel selector valve had been set to Main position; the engine was still drawing fuel from the auxiliary tank which had eventually drained empty and led engine to fail due to fuel starvation. Apparently the fuel selector valve had not been positioned completely in its detent position (had not clicked). After this incident; a good lesson learned and I became more alert and diligent when using the fuel valves to switch between tanks to ensure they are properly positioned. I filled up the tanks; started up the engines and flew the same aircraft for another 40 hours uneventfully.




Synopsis: A PA-30 pilot thought that he switched from the empty AUX fuel tank to a MAIN; but the selector position was not fully in MAIN so the right engine quit. The pilot declared an emergency and ATC vectored him to a nearby airport.