AC50 pilot had a forced off airport landing caused by fuel starvation, when a fuel tank cap came off...

Attributes
ACN	543704
Time
Date	200204
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zhu.artcc
Operator	common carrier : air taxi
Make Model Name	Commander 500
Operating Under FAR Part	Part 135
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument pilot : multi engine pilot : private pilot : cfi
Experience	flight time last 90 days : 250 flight time total : 1750 flight time type : 82
ASRS Report	543704
Person 2
Affiliation	government : faa
Function	controller : radar
Events
Anomaly	aircraft equipment problem : critical non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : landed in emergency condition other
Consequence	other other
Factors
Maintenance	performance deficiency : testing performance deficiency : inspection
Supplementary
Problem Areas	Company Aircraft
Primary Problem	Aircraft

Narrative:

During flight from ZZZ1 to ZZZ at 8000 ft, VFR on top, airplane engines started to sputter. Emergency procedure for fuel exhaustion was performed, but did not help situation. The airplane continued to descend through clouds until ground contact was observed (at 2800 ft MSL). At that time I observed a pasture for landing located below aircraft. I immediately made a 270 degree left turn. When I leveled wings, landing gear was extended. The airplane landed safely on a 500 ft long cow pasture. I received no injuries, nor did the airplane receive any damages. When I exited the airplane I did notice the fuel cap was not attached. Before the flight, I did a thorough preflight, including engine oil levels and fuel level. The airplane was topped off. After departure, I noticed the fuel gauge reading 80 gallons. About 20 mins later it read 50 gallons. I monitored the fuel gauge and noticed it stabilized at 50 gallons. I was 25 mins from ZZZ and determined I had more than enough fuel to reach my destination (the airplane burns 30 gallons of fuel per hour). 5 mins later, the engines stopped. In-flight, I am unable to see if fuel cap is on or off.

Original NASA ASRS Text

Title: AC50 PLT HAD A FORCED OFF ARPT LNDG CAUSED BY FUEL STARVATION, WHEN A FUEL TANK CAP CAME OFF INFLT.

Narrative: DURING FLT FROM ZZZ1 TO ZZZ AT 8000 FT, VFR ON TOP, AIRPLANE ENGS STARTED TO SPUTTER. EMER PROC FOR FUEL EXHAUSTION WAS PERFORMED, BUT DID NOT HELP SIT. THE AIRPLANE CONTINUED TO DSND THROUGH CLOUDS UNTIL GND CONTACT WAS OBSERVED (AT 2800 FT MSL). AT THAT TIME I OBSERVED A PASTURE FOR LNDG LOCATED BELOW ACFT. I IMMEDIATELY MADE A 270 DEG L TURN. WHEN I LEVELED WINGS, LNDG GEAR WAS EXTENDED. THE AIRPLANE LANDED SAFELY ON A 500 FT LONG COW PASTURE. I RECEIVED NO INJURIES, NOR DID THE AIRPLANE RECEIVE ANY DAMAGES. WHEN I EXITED THE AIRPLANE I DID NOTICE THE FUEL CAP WAS NOT ATTACHED. BEFORE THE FLT, I DID A THOROUGH PREFLT, INCLUDING ENG OIL LEVELS AND FUEL LEVEL. THE AIRPLANE WAS TOPPED OFF. AFTER DEP, I NOTICED THE FUEL GAUGE READING 80 GALLONS. ABOUT 20 MINS LATER IT READ 50 GALLONS. I MONITORED THE FUEL GAUGE AND NOTICED IT STABILIZED AT 50 GALLONS. I WAS 25 MINS FROM ZZZ AND DETERMINED I HAD MORE THAN ENOUGH FUEL TO REACH MY DEST (THE AIRPLANE BURNS 30 GALLONS OF FUEL PER HR). 5 MINS LATER, THE ENGS STOPPED. INFLT, I AM UNABLE TO SEE IF FUEL CAP IS ON OR OFF.

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.

AC50 pilot had a forced off airport landing caused by fuel starvation, when a fuel tank cap came off in-flight.