On September 8, 1993, a Boeing 737-300 (registration N350SW) was involved in an aviation accident near St. Louis, MO. Investigators recorded the probable cause as: a failure of the left outboard foreflap due to the loss of the bolts that hold the inboard sequencing carriage to the foreflap attach lug. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 8 related events involving the same aircraft type or operator are linked below.
During final approach, a go-around was executed due to traffic separation. The first officer noted abnormal handling, and cabin attendants reported a left flap issue. An off-duty captain identified a broken foreflap, and the captain landed uneventfully. Examination revealed missing nuts and fractured bolts.
Incident Sequence
The airplane was on final approach when the tower controller requested a go-around for traffic separation. The flight crew executed the go-around. During the maneuver, the first officer, who was flying the airplane, remarked that the airplane was not flying right. Cabin attendants reported a problem with the left flaps. An off-duty captain riding in the cockpit investigated and reported that the left outboard foreflap was broken and hanging loose. The captain then took control and made an uneventful landing.
Examination Findings
Examination of the failed flap assembly found that the nuts were missing on the two aft bolts which hold the inboard sequencing carriage to the foreflap attach lug, and the two forward bolts were fractured.
