Incident Overview
On September 1, 2011, at approximately 1725 central daylight time, a Bombardier CL-600-2B19 (registration N875AS) operating as Delta Connection flight 5058 landed at Baton Rouge Metropolitan Airport (BTR) in Baton Rouge, Louisiana, with the left main landing gear in the retracted position. The flight crew, consisting of an airline transport pilot captain, a first officer, and a flight attendant, along with 50 passengers, were not injured. The airplane sustained minor damage.
Flight Details
The flight originated from Hartsfield Jackson Atlanta International Airport (ATL) in Atlanta, Georgia, at 1409. Visual meteorological conditions prevailed for the landing, and an instrument flight rules flight plan was filed under 14 Code of Federal Regulations Part 121.
Sequence of Events
During configuration for landing, the flight crew observed a landing gear disagree message, and the left main landing gear indicated it was not down and locked. The crew followed Quick Reference Handbook (QRH) procedures, including cycling the landing gear handle and deploying the alternate gear extension (manual release) system. Despite these efforts, the left main landing gear could not be extended. The captain declared an emergency and opted to land with the right main landing gear and nose gear extended. After touchdown, the airplane came to rest in an upright position with the left wing low. The captain ordered an evacuation, and all passengers exited via the left forward door.
Post-Inspection Findings
A post-incident inspection revealed minor damage to the left wing; no other damage resulted from the landing with the left main gear retracted. Examination of the left main landing gear assembly disclosed that the upper attachment bolt for the left main landing gear uplock assembly—designed to secure both the uplock mechanism and the structure—was attached only to the airplane structure, not to the uplock mechanism.
Maintenance Context
Maintenance had been performed on both the left and right main landing gear systems before the incident flight. The mechanic who conducted this maintenance lacked prior experience with installing the uplock assembly. Following the incident, Atlantic Southeast Airlines revised its maintenance requirements and procedures to prevent recurrence. Additionally, Bombardier issued Service Letter ATA:3230 to address the maintenance discrepancy.