An AC50 pilot failed to verify that the fuel cap was installed after a fuel stop. Because the cap wa...

Attributes
ACN	840084
Time
Date	200906
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	Aero Commander 500 Series
Operating Under FAR Part	Part 135
Flight Phase	Landing
Route In Use	Direct Visual Approach
Flight Plan	IFR
Component
Aircraft Component	Fuel Tank Cap
Person 1
Function	Captain Single Pilot Pilot Flying
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor Flight Crew Commercial
Experience	Flight Crew Last 90 Days 180 Flight Crew Total 2400 Flight Crew Type 1400
Events
Anomaly	Deviation - Procedural FAR Deviation - Procedural Published Material / Policy Inflight Event / Encounter Fuel Issue

Narrative:

I was flying this route for the last 3 nights and it's pretty simple; there and back deal. I always get a top-off at my destination since it's about $0.50 cheaper. I noticed two line guys working on my plane tonight; but figured they did the job. Did a quick glance to check the cap and it looked like it was there; but it was dark so I wasn't 100% sure. I did not double-check the cap. My cargo showed up so I fired up the engines and took off.about 25-30 minutes into the flight I saw my gauge show 90 gallons. The commander has 5 fuel cells all interconnected; one fuel inlet; 2 outlets to the engines in the central tank; so the cap is pretty important since one tank can't be isolated from the rest. Looking back at my gauge; I began to think it was showing right. But another 10 minutes in; I was down another 20 gallons. I was using around 120 gallons per hour; the normal flow is 30 per hour. I was immediately thinking for outs in case I wouldn't be able to make it back to base. In the end; I landed with about 20 gallons in the tank or about 10 minutes left.my inattentiveness to doing a through pre-flight during my turnaround and the fact I did not physically check the fuel cap caused this event. Also when I realized I did have a problem; I continued the flight rather than divert pushing the safety margin.

Original NASA ASRS Text

Title: An AC50 pilot failed to verify that the fuel cap was installed after a fuel stop. Because the cap was not installed fuel rapidly siphoned from the interconnected tanks resulting in critically low fuel at the destination.

Narrative: I was flying this route for the last 3 nights and it's pretty simple; there and back deal. I always get a top-off at my destination since it's about $0.50 cheaper. I noticed two line guys working on my plane tonight; but figured they did the job. Did a quick glance to check the cap and it looked like it was there; but it was dark so I wasn't 100% sure. I did not double-check the cap. My cargo showed up so I fired up the engines and took off.About 25-30 minutes into the flight I saw my gauge show 90 gallons. The Commander has 5 fuel cells all interconnected; one fuel inlet; 2 outlets to the engines in the central tank; so the cap is pretty important since one tank can't be isolated from the rest. Looking back at my gauge; I began to think it was showing right. But another 10 minutes in; I was down another 20 gallons. I was using around 120 gallons per hour; the normal flow is 30 per hour. I was immediately thinking for outs in case I wouldn't be able to make it back to base. In the end; I landed with about 20 gallons in the tank or about 10 minutes left.My inattentiveness to doing a through pre-flight during my turnaround and the fact I did not physically check the fuel cap caused this event. Also when I realized I did have a problem; I continued the flight rather than divert pushing the safety margin.

Data retrieved from NASA's ASRS site as of April 2012 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.