20021121032859I

(-23) Aircraft was on a part 61 training flight. The student was receiving dual instruction for the ATP rating. During a normal landing and after the nose wheel had touched down on runway 30 at lgb, the nose gear collapsed after a few seconds. All gear indications were normal. The pilot statements and a witness statement indicated that a normal landing was made. The statements did not include any conflicting information. The aircraft sustained minor damage to the nose fairing and gear doors. Both engines incurred propeller damage and sudden stoppage. There had been two previous ad's issued for inadvertent nose gear retraction after landing applicable to this aircraft which had been complied with. AD 80-12-03 was complied with on may 30, 1980. This AD included a requirement to install "Piper nose gear downlock hook and bushing replacement kit", Piper part number 764-101V. Included in this kit was a downlock hook, an eccentric bushing, one bolt and a nut plate. During inspection of aircraft, it was noted that the nose gear downlock bolt with the eccentric bushing had broken at the nutplate and could not be located. This contributed to an inadvertent nose gear retraction.