On April 30, 1997, a Cessna 140 (registration N2031N) was involved in an aviation accident near Palo Alto, CA. Investigators recorded the probable cause as: the pilot's failure to obtain and/or maintain adequate airspeed during initial climb after takeoff, which resulted in an inadvertent stall and collision with the terrain. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
The pilot of a modified airplane lost control shortly after takeoff, causing the aircraft to crash. The modification, which increased fuel capacity and stall speed, was not FAA-approved.
Accident Sequence
The pilot, who was also the owner and operator of the airplane, applied engine power for takeoff. The airplane accelerated and climbed to approximately 50 feet above the runway. Suddenly, the airplane banked to the right. The pilot attempted to lower the left wing by applying opposite aileron, but his efforts were inadequate. He lost control of the airplane as the nose pitched down, and the airplane crashed. It came to rest in an open dirt field about 150 feet from the runway's edge.
Pilot Report
The pilot reported that no mechanical malfunction or failures were experienced during the flight.
Aircraft Modification
An examination of the airplane revealed that it had been modified by the addition of fuel tanks. This modification increased the total fuel tank capacity from the standard 25 gallons to about 60 gallons. The pilot reported that this modification, which was performed under his direction, had increased the airplane's stall speed by 6 mph. The Federal Aviation Administration (FAA) had not approved the modification.