Accident Details
On September 18, 2010, at approximately 1145 central daylight time, a Cessna 320, registration N56VP, operated by the Association of Orthopedic Services PA, Grand Prairie, Texas, sustained substantial damage when its nose gear folded during landing on runway 17 at Denton Municipal Airport (DTO), Denton, Texas. Visual meteorological conditions prevailed at the time. The instructional flight was conducted under 14 Code of Federal Regulations Part 91 without a flight plan. The instructor and pilot on board were not injured. The flight had originated at Grand Prairie Municipal Airport (GPM) around 0930.
Flight Sequence
According to the flight instructor's accident report, the purpose of the flight was to administer a flight review and insurance endorsement to the pilot. After conducting four touch-and-go landings at Decatur Municipal Airport (LUD), Texas, the flight proceeded to Decatur's Bishop Field (76T) to perform a soft field landing on the grass runway. When the landing gear was extended, the gear down and locked light did not illuminate. The annunciator lights were checked using the press-to-test feature and operated normally. The convex mirrors on the engine nacelles confirmed that the nose gear was only partially extended. The landing gear was cycled several times and manually extended at least three times. "G snaps" were performed but did not resolve the issue. The instructor subsequently landed the airplane on DTO's runway 17, during which the nose gear folded.
Post-Accident Inspection
Post-accident inspection revealed that the push-pull rod that passes through the main spar and connects the gear transmission to the nose gear had separated. This separation damaged the main spar and several fuselage ribs.
Maintenance Requirements
The Cessna 320 Maintenance Manual requires that the main and nose gear drive tubes and idler mechanism, as well as rigging and clearance, be checked every 100 hours or 12 months, whichever comes first.