Narrative:

Commercial multi engine training flight. Took off on runway 16 for pattern work. After 2.7 hours of training we returned to base airport. Student did a normal takeoff and I instructed him to do a normal landing (both engines). During this pattern student was doing good (followed procedures and checklist) and we requested a touch and go. (Gears were down 3 green; no red and '400 AGL gear down; three green' callout was completed). Final approach was stable and did a nice touchdown. During the upwind-crosswind turn I instructed the student to do a short field landing (both engines). Abeam the numbers; student extended the gear down (confirmed gear down; 3 green; no red) and student did his before landing checklist. Winds were gusting not exactly sure how strong but within company limitations as well as aircraft manufacturer limitations. As he continued base to final 400 feet AGL student called 'gear down; 3 green' as I did the same and visually confirmed. Short final; student was slightly low on approach and told him to add power; which he did. As he flared and touched down I felt the main landing gear touch the runway and suddenly I heard the gear horn go off which should never happen and as I looked toward the landing gear handle; the gear lever was in the up position. I simultaneously took the controls and extended the gear handle back down. One to two seconds after that; I visually saw that we were sinking and started to hear metal scrape the ground. I immediately cut all mixtures; props; throttle to idle/feather. The aircraft by this time was veering toward the right toward the grass and I called tower that we 'crash landed'. I then called tower and my company frequency on this incident. Conclusion: upon touchdown of the main landing gear; student raised the gear handle up with his knee by accident; inadvertently. Next day; I assessed the damage with my chief pilot and realized that the landing gear handle can be raised and lowered without pulling the gear handle out then raised/lowered. The 'stop switch/metal stop' was worn out which caused the gear handle to go up without pulling the handle out and then raised up.

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Original NASA ASRS Text

Title: A BE76's landing gear handle detent was severely worn so that it did not remain locked in the down detent. On short final the student pilot's leg hit the handle causing the gear to retract and the aircraft subsequently landed gear up.

Narrative: Commercial multi engine training flight. Took off on Runway 16 for pattern work. After 2.7 hours of training we returned to base airport. Student did a normal takeoff and I instructed him to do a normal landing (both engines). During this pattern student was doing good (followed procedures and checklist) and we requested a touch and go. (Gears were down 3 green; no red and '400 AGL gear down; three green' callout was completed). Final approach was stable and did a nice touchdown. During the upwind-crosswind turn I instructed the student to do a short field landing (both engines). Abeam the numbers; student extended the gear down (confirmed gear down; 3 green; no red) and student did his before landing checklist. Winds were gusting not exactly sure how strong but within company limitations as well as aircraft manufacturer limitations. As he continued base to final 400 feet AGL student called 'gear down; 3 green' as I did the same and visually confirmed. Short final; student was slightly low on approach and told him to add power; which he did. As he flared and touched down I felt the main landing gear touch the runway and suddenly I heard the gear horn go off which should never happen and as I looked toward the landing gear handle; the gear lever was in the up position. I simultaneously took the controls and extended the gear handle back down. One to two seconds after that; I visually saw that we were sinking and started to hear metal scrape the ground. I immediately cut all mixtures; props; throttle to idle/feather. The aircraft by this time was veering toward the right toward the grass and I called tower that we 'crash landed'. I then called Tower and my company frequency on this incident. Conclusion: upon touchdown of the main landing gear; student raised the gear handle up with his knee by accident; inadvertently. Next day; I assessed the damage with my Chief Pilot and realized that the landing gear handle can be raised and lowered without pulling the gear handle out then raised/lowered. The 'stop switch/metal stop' was worn out which caused the gear handle to go up without pulling the handle out and then raised up.

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.