The Incident as a Situational example

You are at the end of a transatlantic flight and start your approach. In addition to your first officer, your crew is complemented by a non-handling cruise relief pilot (CRP) for duty time extension.

After takeoff, the landing gear took a little longer than usual to retract, but there were no abnormal indications or alert messages, and hydraulic system quantity indications were normal.

The flight proceeded uneventfully except that during cruise, as part of routine checks of systems, the no. 6 brake temperature indicator appeared to be malfunctioning.

The flight continued normally until the airplane was about 8 nm (15 km) out on final approach to the runway. On selection of landing gear down, an unsafe alert appears, telling you that the left main gear is neither down nor locked and that the gear door is only partially open.