Incident Overview
A post-landing examination of a United Airlines aircraft by personnel from United Airlines and the Federal Aviation Administration (FAA) revealed that the left off-wing escape slide had deployed without inflating. The slide was observed hanging from the aircraft's fuselage.
Findings from Maintenance and Engineering Inspections
Further examination by United maintenance personnel showed that the slide carrier tray assembly had rotated out to the open position. The off-wing slide compartment, door, and operating latch mechanism were inspected and no discrepancies were noted. Additional examination of the off-wing escape slide assembly by Boeing engineering personnel found no evidence of mechanical malfunction with the system.
Maintenance History
Maintenance records indicated that the off-wing escape slide pack had been replaced on May 15, 2006, four flights before the slide deployment occurred. This replacement was performed in accordance with routine scheduled maintenance intervals for the assembly. The maintenance work was completed and inspected by United Airlines personnel at a maintenance facility in Chicago, Illinois.
Cause Determination
A post-incident Maintenance Investigation report submitted to the National Transportation Safety Board (NTSB) by United Airlines stated that the inadvertent deployment of the off-wing slide assembly was the result of the carrier tray not being locked in the stowed position.