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n November, VFA-83 left for a COMPTUEX detachment aboard USS Dwight D. Eisenhower (CVN-69) in preparation for an upcoming deployment. During the first week of the detachment, aircraft 312 started venting fuel after in-flight refueling. After reviewing the A1-F18AE-460-200 troubleshooting-manual, we decided to run a test to troubleshoot the overfilling vent-tank. The test indicated that the right-wing high-level-pilot-valve and the refuel shut-off valve had failed, causing the wing tank to over-fill the internal cells. After removing and replacing the defective components, we repeated the test. This time, the internal cells did not overfill; we returned the aircraft to service. The next day the aircraft flew two flights with no discrepancies. On the third flight, however, the problem returned. After passing the refuel test a
Spring 2010
second time, we decided to test the fuel-pressurizationsystem. This test showed that the left-wing motive-flow shut-off valve had failed. After replacing this component and successfully re-testing the system, maintenance returned 312 to service. Two days later—after several component changes— we still had not identified the gripe’s cause. Our tech reps were just as puzzled. During our previous deployment, we had faced a similar issue and had developed troubleshooting procedures that will soon be incorporated into the troubleshooting manuals. We decided to apply some of the lessons learned from last deployment to our current head-scratcher of a problem. First, we dropped the port-side motor to access the vent tank. An inspection of the area revealed that the y-line from the fuel dump was cracked and likely a contributing factor to our ongoing discrepancy. After replacing the automatic drain-valve in the vent tank— and repairing the y-line—we prepared to refuel the aircraft and check our work. While refueling with electrical power, we noticed cell-4 was not pre-checking. Back into the fuel cell we
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