What happened
On July 10, 2010, at 2205 CDT, a Cessna 421/A, registration N88DF, impacted trees and terrain approximately 0.5 miles north of Tulsa International Airport (TUL) in Oklahoma. The aircraft was performing a visual approach to Runway 18R when it experienced a dual loss of engine power. The accident resulted in 3 fatal injuries, claiming the lives of the pilot and two pilot-rated passengers.
The flight originated at Oakland County International Airport (PTK) in Michigan. Prior to departing PTK for the return leg to Tulsa, a fuel leak occurred during preflight when the right main tank sump became stuck open. A line serviceman observed an estimated loss of five to six gallons of fuel, which was not replaced. During the flight, the pilot requested a diversion from the original destination, Richard Lloyd Jones Jr. Airport (RVS), to TUL. At 2204:23, the pilot notified air traffic control that the aircraft had exhausted fuel. The airplane then descended into a forested area, followed by a flash.
The investigation
Investigators examined the wreckage and found the right main fuel tank had been separated from the wing due to impact. While the engines were examined and found to be capable of normal operation, the fuel flow indicator showed that the aircraft had used 170.8 gallons of its 196-gallon usable capacity. GPS data indicated the pilot's decision to land at Runway 18R instead of 18L added at least one mile to the flight path.
Findings
- The pilot's inadequate preflight fuel planning and in-flight fuel management led to the total loss of engine power.
- The loss of approximately five to six gallons of fuel during preflight, combined with the extended flight distance, depleted the usable fuel.
- The pilot's use of performance-impairing medications, specifically cyclobenzaprine and diphenhydramine, contributed to the accident.