On June 29, 1986, a Piper PA-23-160 (registration N17278) operated by John Welniak was involved in an aviation accident near Upland, CA. Investigators recorded the probable cause as: The pilot's failure to complete the pre-landing checklist, specifically neglecting to lower the landing gear while practicing single-engine procedures. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot practicing single-engine procedures forgot to extend the landing gear. After being alerted by another pilot, he attempted to retract it but landed with partial extension, colliding with parked aircraft.
What happened
The pilot was conducting a flight focused on practicing single-engine procedures when he realized he had failed to lower the landing gear prior to landing. Another pilot monitoring the radio traffic alerted him to the oversight. In response, the pilot attempted to extend the landing gear but was only able to partially lower it before touchdown. He elected to land on the taxiway rather than continuing the approach, resulting in a collision with three unoccupied parked aircraft.
The investigation
Post-accident examination revealed that the landing gear was only partially extended at the time of impact. The pilot confirmed that the omission of the landing gear check was due to distraction while managing the single-engine simulation procedures.
Probable cause
The pilot's failure to complete the pre-landing checklist, specifically neglecting to lower the landing gear while practicing single-engine procedures.