Narrative:

On approach to ZZZ; noticed rh fuel indication had dropped to 300lbs lower than the lh fuel indicator. No action taken in the air as I was on the ILS approach and total fuel was not low.upon landing and parking; I noticed a substantial fuel leak and local airport operations and fire department were notified due to the size of the spill. The spill was contained and the aircraft grounded until a replacement part could be installed. Initially became aware of the fuel problem in flight on approach into ZZZ. The cause of the fuel problem was identified on the ground after shut down. After conferring with ZZZ1 maintenance; it was determined that a quick drain plug had come loose and fell out of its place during flight.

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Original NASA ASRS Text

Title: SA-227 Captain reported a fuel imbalance during flight led to discovery of a fuel leak after landing.

Narrative: On approach to ZZZ; noticed RH fuel indication had dropped to 300lbs lower than the LH fuel indicator. No action taken in the air as I was on the ILS approach and total fuel was not low.Upon landing and parking; I noticed a substantial fuel leak and local airport operations and fire department were notified due to the size of the spill. The spill was contained and the aircraft grounded until a replacement part could be installed. Initially became aware of the fuel problem in flight on approach into ZZZ. The cause of the fuel problem was identified on the ground after shut down. After conferring with ZZZ1 maintenance; it was determined that a quick drain plug had come loose and fell out of its place during flight.

Data retrieved from NASA's ASRS site 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.