Incident Overview
An airline transport pilot reported that before landing after an uneventful flight, he extended the wing flaps to the approach position and lowered the landing gear, with the gear indicator lights showing three green. After touchdown, he heard noises and the airplane began to sink. The airplane came to a stop on the right side of the runway, at which point the pilot noticed that the landing gear handle was in the up position. He asked the copilot, "How did the gear handle get up?" then moved the handle to the down position, and both flight crew exited the airplane.
The copilot stated he was acting as an observer during the flight and also saw three green landing gear down-and-locked indicator lights before landing.
Damage and Wreckage Examination
The airframe sustained substantial damage from contact with the runway. All three landing gear were found in a partially-extended position. Skid marks from all three tires were observed on the runway leading up to the main wreckage. Both propeller assemblies were damaged due to contact with the runway. The pressure vessel was compromised from contact with a propeller blade, and the nose landing gear actuator was forced up into the nose gear well, penetrating the upper nose skin.
Examination of the landing gear components revealed no evidence of a preexisting mechanical malfunction. The skid marks and the partially-extended gear were inconsistent with the pilot's account that the gear handle was up after the airplane came to rest and was then lowered.
Gear Handle and System Design
The gear handle consisted of an electrical switch that required it to be pulled out of a detent before moving up or down. There was no mechanical linkage between the gear handle and the landing gear; the gear were driven by an electric motor.
Pilot's Condition and Actions
The pilot reported experiencing several interruptions to his sleep the night before the accident. On the day of the accident, he flew 7 legs for a total of 5.2 hours and only ate a banana for breakfast during that time. It is likely that the pilot realized the gear were not extended just before touchdown and then tried to lower them, resulting in touchdown with the gear only partially extended. It is likely that the pilot's fatigue contributed to his failure to ensure that the landing gear were down and locked before landing.