Date: 201204
Local time of day: 0001-0600
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Night
Aircraft: B737-300
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Fuel Crossfeed
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Confusion; Distraction; Time Pressure; Workload; Training / Qualification
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue
Detector: Person Flight Crew
When detected: In-flight
Result: Aircraft Equipment Problem Dissipated; Flight Crew Became Reoriented; Flight Crew FLC complied w / Automation / Advisory; General Declared Emergency
Contributing factors: Aircraft; Human Factors; Procedure
Primary problem: Ambiguous

Narrative: Prior to descent; I started to cross-feed the fuel system to balance the tank quantity. (The right side was approximately 250 LBS lower than the left.)  ATC gave us a descent to FL240.  At the start of descent; after I pulled the thrust levers to flight idle; I noticed the right side fuel was now approximately 350 LBS lower and that my cross-feeding balance was not working. At about the same time I was looking at the fuel; the engine warning lights associated with an engine failure illuminated.  I noticed that I had inadvertently failed to open the cross feed valve during balancing; or I inadvertently closed it; so I immediately turned the number 2 fuel boost pumps back on. The First Officer said we had an engine flameout on the number 2 engine.  I continued to fly the aircraft and told him to run the Engine Failure Checklist in the QRH.  ATC called us a few times to verify that we were going to level at FL240 since there was traffic below us. We told ATC we were working a problem with a flamed out engine and that we would call them back. ATC asked us if we wanted to declare an emergency and we told them to stand by as we were running a checklist. ATC then gave us direct to our filed destination. We restarted the engine IAW the procedures in the QRH.  As were reviewed all the items in the QRH; the First Officer and I discussed which airport was the most suitable for landing. We determined that our filed destination was the safest option.  I rang the flight attendant call button; so that they would start the cleanup process for landing and heard them talk on the PA. We notified ATC that we had restarted our engine.  ATC asked if we needed any assistance and if we were declaring an emergency.  The First Officer and I discussed if we needed to be an emergency since our engine was restarted and we decided that were we not an emergency at that time.  In retrospect; we should have immediately declared an emergency. We sent a quick ACARS message to Dispatch explaining that we had an engine flameout and restart and were continuing. We continued the descent and did a visual landing.  We should have declared an emergency with ATC as soon as we lost our engine. Even after we successfully restarted the engine; we should have declared an emergency with ATC. To prevent an inadvertent closure of the cross-feed valve during fuel balancing; I should have been louder in verbalizing my actions; and I should have been slower and more deliberate in my switch moving. I should have informed the flight attendants about the situation; even after the engine was restarted. Upon debriefing with Maintenance Control; they said the engine should have continued to run by gravity feed even if the cross-feed valve was closed with the boost pumps off.  Maintenance is looking at the engine to determine what system malfunction occurred.


Second narrative: [No additional information]


Synopsis: A B737-300 Captain mis-set the fuel cross-feed system and starved the engine; resulting in a flame out; but was a restart was successful. Maintenance stated the engine should have suction-fed fuel.