Small aircraft declares emergency as engine sputters even though airport closed.

Attributes
ACN	244535
Time
Date	199306
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : smo
State Reference	CA
Altitude	agl bound lower : 1400 agl bound upper : 1400
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tower : smo
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	descent : approach other other
Route In Use	enroute : direct
Flight Plan	VFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 20 flight time total : 350 flight time type : 230
ASRS Report	244535
Person 2
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Left san carlos with full fuel. Landed oxnard airport after a 2 1/2 hour flight. Departed for santa monica just before sunset. Received ATIS information and called the tower over topanga canyon and was informed that the airport was closed. After starting a climb to clear the hills to van nuys where I am based, my engine began to sputter. I switched tanks immediately and the engine performance was again normal. My flight calculations would have left me over an hour of fuel with the majority in the right tank. I was on the right tank when the engine began to sputter. I did not feel that I should take the chance of flying over the hills and city to van nuys when the beach and santa monica airport were in sight. I declared a fuel emergency, exercised my PIC authority to land, and did so without further incident. I later found that the right fuel cap was missing from the aircraft. I further deduced that the fuel must have siphoned from the tank.

Original NASA ASRS Text

Title: SMA DECLARES EMER AS ENG SPUTTERS EVEN THOUGH ARPT CLOSED.

Narrative: LEFT SAN CARLOS WITH FULL FUEL. LANDED OXNARD ARPT AFTER A 2 1/2 HR FLT. DEPARTED FOR SANTA MONICA JUST BEFORE SUNSET. RECEIVED ATIS INFO AND CALLED THE TWR OVER TOPANGA CANYON AND WAS INFORMED THAT THE ARPT WAS CLOSED. AFTER STARTING A CLB TO CLR THE HILLS TO VAN NUYS WHERE I AM BASED, MY ENG BEGAN TO SPUTTER. I SWITCHED TANKS IMMEDIATELY AND THE ENG PERFORMANCE WAS AGAIN NORMAL. MY FLT CALCULATIONS WOULD HAVE LEFT ME OVER AN HR OF FUEL WITH THE MAJORITY IN THE R TANK. I WAS ON THE R TANK WHEN THE ENG BEGAN TO SPUTTER. I DID NOT FEEL THAT I SHOULD TAKE THE CHANCE OF FLYING OVER THE HILLS AND CITY TO VAN NUYS WHEN THE BEACH AND SANTA MONICA ARPT WERE IN SIGHT. I DECLARED A FUEL EMER, EXERCISED MY PIC AUTHORITY TO LAND, AND DID SO WITHOUT FURTHER INCIDENT. I LATER FOUND THAT THE R FUEL CAP WAS MISSING FROM THE ACFT. I FURTHER DEDUCED THAT THE FUEL MUST HAVE SIPHONED FROM THE TANK.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.