Narrative:

Base turn to final on the visual approach in VMC we experienced a landing gear malfunction. During configuration; the nose and right main gear extended and locked; but the left main gear did not. The 'transit' light went out in the gear handle but there was no green light for the left main. We immediately notified ATC and received vectors to allow time for communication with company and checklist completion. While receiving our new heading and altitude; tower mentioned that our left main gear did not appear to be down. We performed the 'gear down-unsafe condition' checklist; recycled the gear twice; were presented with the same indications and then were referred to the emergency landing checklist. Before proceeding with the emergency landing checklist; we contacted dispatch to coordinate a plan. In doing so; the emergency landing handle was pulled in accordance with maintenance control and then the first officer observed the gear to be down from the cabin of the aircraft. The passengers were relocated to the rear right side of the cabin and briefed on the emergency procedures as well as the brace position. The landing was uneventful and upon clearing the runway we contacted dispatch again. Given there appeared to be nothing wrong with the plane and that the left main gear was in fact down and locked; we decided to taxi to the gate and deplane. Before leaving the plane; maintenance -- who was waiting for us at the gate -- notified us that there was a 'cannon plug' out of position in the left main gear well.

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Original NASA ASRS Text

Title: A faulty cannon plug on the left main landing gear resulted in some tense moments for and SF340 flight crew when they failed to obtain a gear safe indication.

Narrative: Base turn to final on the visual approach in VMC we experienced a landing gear malfunction. During configuration; the nose and right main gear extended and locked; but the left main gear did not. The 'transit' light went out in the gear handle but there was no green light for the left main. We immediately notified ATC and received vectors to allow time for communication with company and checklist completion. While receiving our new heading and altitude; Tower mentioned that our left main gear did not appear to be down. We performed the 'Gear Down-Unsafe Condition' checklist; recycled the gear twice; were presented with the same indications and then were referred to the Emergency Landing checklist. Before proceeding with the Emergency Landing checklist; we contacted Dispatch to coordinate a plan. In doing so; the emergency landing handle was pulled in accordance with Maintenance Control and then the First Officer observed the gear to be down from the cabin of the aircraft. The passengers were relocated to the rear right side of the cabin and briefed on the emergency procedures as well as the brace position. The landing was uneventful and upon clearing the runway we contacted Dispatch again. Given there appeared to be nothing wrong with the plane and that the left main gear was in fact down and locked; we decided to taxi to the gate and deplane. Before leaving the plane; maintenance -- who was waiting for us at the gate -- notified us that there was a 'cannon plug' out of position in the left main gear well.

Data retrieved from NASA's ASRS site as of April 2012 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.