Skywagon 185
Flight Crew Flight Engineer; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 25; Flight Crew Total 21350; Flight Crew Type 1000
Situational Awareness; Confusion
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown; Inflight Event / Encounter Fuel Issue
Flight Crew Landed in Emergency Condition
Human Factors; Procedure
I originally left [home airport] with my aircraft with full fuel (78 gallons useable) on a 1+10 hours direct flight. During the course of the approximately 30 days between the departure date and my return date to [home airport]; I conducted numerous short flights (9 roundtrips) of 11 minutes duration each way. Each of these flights required a high power climb to 2;000-2;500 feet MSL for overwater single engine operation. I also conducted two round trips of 20 minutes each way with similar climb requirements. I tracked my flight time meticulously with the use of the on board GPS system over the course of the time period prior to my return trip. I departed with 5.4 hours of flight time on the full fuel tanks planning on having 2.0 hours of fuel left for the 1.2 hour flight. I ran out of fuel 52 minutes into my flight and landed on a highway. There was no damage or injuries to myself; the plane; or anyone on the ground fortunately.I have owned the incident aircraft for approximately 25 years and I have never run out of fuel in any aircraft over the course of my [long] aviation career. In retrospect; I obviously failed to consider the increased fuel consumption due to the numerous takeoffs during the course of the 30 days. I allowed my familiarity with the incident aircraft and the route flown to influence my judgment and make some not so smart decisions regarding fuel for the return flight. I could have easily landed [short] to buy 10 gallons of AVGAS as a safety margin but I was sure I had enough fuel obviously. Poor decision and judgment on my part and I assure you it will not happen again.
The pilot of a Cessna 185 utilized accumulated time flown on several legs over a 30 day period to track available fuel; only to run out of fuel approximately 18 minutes short of his destination.