Incident Overview
During the landing flare, the airplane made initial contact with the runway on its landing gear, then briefly rose back into the air. The pilot stated that he held the airplane in ground effect, and when it settled back toward the runway, the landing gear folded up as the wheels touched the ground.
Witness Observations
Witnesses reported that the landing gear was extended at the time of touchdown.
Examination Findings
Post-incident examination revealed the left and right nose gear doors were still attached to the airframe along the full length of their respective hinges. The right nose gear door showed no scraping or damage. The left nose gear door exhibited scrape marks on the vent fins and a localized scrape mark on the inboard edge of the door. This localized scrape mark corresponded with the location of the nosewheel tire when in the retracted position behind the door. No damage was observed on the nose gear assembly.
Examination of the right main landing gear found no damage to the gear door or the wheel hub cap. However, the radar pod beneath the airplane's right wing displayed scrape damage. The left main landing gear showed no damage to its gear door, but the wheel hub cap was scraped around its entire center circumference.
System Functional Test
Functional testing of the landing gear system showed no evidence of malfunction.
Conclusion
The investigation did not determine a probable cause for the gear collapse. The source does not provide a stated cause.