Cessna 421/A Fuel Exhaustion Accident at Tulsa International Airport (N88DF)

Accident Overview and Flight History On July 10, 2010, at 2205 Central Daylight Time, a Cessna model 421/A, registration N88DF, impacted trees and terrain in Mohawk Park, approximately one-half mile north of Tulsa International Airport (TUL), following a dual loss of engine power. The accident occurred during a visual approach to Runway 18R. The private pilot and two pilot-rated passengers were fatally injured. The aircraft, owned and operated by the pilot, was conducting a business flight under 14 CFR Part 91 without a flight plan. The cross-country flight originated at Oakland County International Airport (PTK), Michigan, with an intended destination of Richard Lloyd Jones Jr. Airport (RVS), Tulsa. The pilot requested a diversion to TUL shortly before the accident. ## Fuel System and Pre-Departure Events The aircraft was configured with an eight-tank fuel system, providing a capacity of 196 gallons of usable fuel for the accident flight. The left wing locker tank was placarded “INOP” and the right wing locker tank was not used. Prior to departing PTK, the pilot requested a fuel top-off. A line serviceman observed the right main tank sump become stuck open during the pilot’s preflight inspection, resulting in an estimated loss of five to six gallons of 100LL aviation fuel. The lost fuel was not replaced. ## Approach and Impact At 2157:50, the pilot requested to land at TUL and was directed to enter a left base for Runway 18R. At 2201:56, the pilot received clearance to land. At 2204:23, the pilot stated, “Tulsa, we’ve exhausted our fuel.” The aircraft was observed descending into a forested area, followed by a flash. The pilot did not inform air traffic control of a fuel problem prior to reporting the exhaustion. ## Aircraft and Engine Examination The aircraft struck 50-to-60-foot-tall trees on an approximate 180-degree magnetic heading. The debris field measured approximately 200 feet long and 75 feet wide. The fuselage came to rest inverted 200 feet south of the first tree strike. A post-impact fire damaged the right wing, right engine cowling, and right locker structure. Examination of both engines revealed no anomalies that would have prevented normal operation. Propellers were found in the feathered position with no leading-edge impact or rotational signatures. ## Toxicology and Medical Findings Toxicological testing on the pilot detected cyclobenzaprine, diphenhydramine, and phentermine in the blood. Cyclobenzaprine and diphenhydramine carry warnings that they may impair mental or physical abilities required for hazardous tasks. Phentermine is not approved for use among pilots by the Federal Aviation Administration. Testing on the pilot-rated passenger detected dextrorphan in the urine, which is not considered impairing.