On August 23, 1989, a Mooney M20F (registration CFSAB) was involved in an aviation accident near Livermore, CA. Investigators recorded the probable cause as: THE PILOT'S DECISION TO CONDUCT LOW LEVEL NIGHT FLIGHT UNDER LOW CEILINGS. CONTRIBUTING FACTORS WERE: THE DARK NIGHT, LOW CEILING, AND HIGH OBSTRUCTIONS. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
An aircraft struck electrical transmission lines installed by Lawrence Livermore Laboratory on 200-ft towers east of Livermore Airport. The main wreckage and separated wing tip were found near the lines.
Incident Overview
On August 18, a flight departed Livermore for an extended trip. During the pilot's absence, Lawrence Livermore Laboratory had installed electrical transmission lines on 200-foot towers on hills approximately six miles east of the airport. The lines crossed a highway and were situated about 300 to 400 feet above the valley floor.
Local Operating Practices
According to local pilots, when fog or low ceilings covered the airport, it was common practice to overfly the airport in an easterly direction until the ground became visible, then descend and reverse course under the clouds, following the highway westward to the airport.
Wreckage and Witness Reports
The main wreckage was discovered 300 yards west of the transmission lines and north of the highway. The right wing tip had been torn from the wing and was found directly under the lines. Ground witnesses reported that the sky was overcast, with an estimated ceiling of 200 feet.