Narrative:

The original destination was 622 NM by GPS. Average TAS of 130 KTS, time en route considered to be approximately 4 hours 40 mins. Fuel tanks were topped that morning by me with 60 gallons of 100LL usable fuel before departure. VMC prevailed the entire flight. Ground speed checks averaged 125 KTS to 130 KTS. While en route, I considered that my fpr was closer to 710 NM, 88 NM greater than the direct GPS determined distance. After approximately 4 hours en route, I changed my destination to ZZZ, 105 NM closer. The first 3.5 hours of flight was conducted at 7000 ft MSL with 2250 inches of manifold pressure and 2400 RPM at 1450 degrees egt. The last 1.5 hours of flight was conducted at 5000 ft MSL with 23 inches of manifold pressure and 2400 RPM at 1450 degrees egt. I experienced fuel exhaustion approximately 4.5 hours into the flight while cruising at 5000 ft MSL. A successful power-off, off-airport landing was made on a road. No injuries were incurred and damage was limited to the starboard wingtip/leading edge due to contact with a street sign. ATC was notified initially of a rough engine and subsequent imminent emergency landing. Upon securing the aircraft off the road, contact was again made with ATC via a handheld radio and a circling piper cherokee (aircraft Y) above. ATC was informed of my location and no injury status. ATC informed me that emergency fire and rescue and state police were informed. Visual inspection of the wing tanks by me and person X. Emergency services concluded there was no visible fuel on board. Emergency services provided me with 11 gallons of 100LL. The wingtip was examined by me (certified a&P), preflight conducted, system checked and the aircraft was determined to be airworthy by me. With the knowledge and consent of all auths involved, I flew the aircraft VFR from this location to ZZZ2. I anticipated closer to 10 gph fuel burn versus the 13 gph fuel burn experienced. Pilot error aside, from a risk management perspective, possible mitigating circumstances include: a fuel venting issue of some type and/or excessive high/rich fuel consumption, inaccurate egt, and/or improper consideration that tanks are full even if fuel is not running out of the top of the wing before fuel caps are installed. No matter the education, certificates and experiences, this can happen to anyone. Regardless of fuel venting issues, excessive fuel burn, inaccurate egt or other possible mitigating factors, don't rely exclusively on arithmetic, charts and graphs. If the fuel gauges say empty -- land! If you don't, prepare to be embarrassed, humiliated and humbled by this sobering experience.

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Original NASA ASRS Text

Title: C177 PLT MAKES AN OFF-FIELD LNDG ON A ROAD DUE TO FUEL EXHAUSTION.

Narrative: THE ORIGINAL DEST WAS 622 NM BY GPS. AVERAGE TAS OF 130 KTS, TIME ENRTE CONSIDERED TO BE APPROX 4 HRS 40 MINS. FUEL TANKS WERE TOPPED THAT MORNING BY ME WITH 60 GALLONS OF 100LL USABLE FUEL BEFORE DEP. VMC PREVAILED THE ENTIRE FLT. GND SPD CHKS AVERAGED 125 KTS TO 130 KTS. WHILE ENRTE, I CONSIDERED THAT MY FPR WAS CLOSER TO 710 NM, 88 NM GREATER THAN THE DIRECT GPS DETERMINED DISTANCE. AFTER APPROX 4 HRS ENRTE, I CHANGED MY DEST TO ZZZ, 105 NM CLOSER. THE FIRST 3.5 HRS OF FLT WAS CONDUCTED AT 7000 FT MSL WITH 2250 INCHES OF MANIFOLD PRESSURE AND 2400 RPM AT 1450 DEGS EGT. THE LAST 1.5 HRS OF FLT WAS CONDUCTED AT 5000 FT MSL WITH 23 INCHES OF MANIFOLD PRESSURE AND 2400 RPM AT 1450 DEGS EGT. I EXPERIENCED FUEL EXHAUSTION APPROX 4.5 HRS INTO THE FLT WHILE CRUISING AT 5000 FT MSL. A SUCCESSFUL PWR-OFF, OFF-ARPT LNDG WAS MADE ON A ROAD. NO INJURIES WERE INCURRED AND DAMAGE WAS LIMITED TO THE STARBOARD WINGTIP/LEADING EDGE DUE TO CONTACT WITH A STREET SIGN. ATC WAS NOTIFIED INITIALLY OF A ROUGH ENG AND SUBSEQUENT IMMINENT EMER LNDG. UPON SECURING THE ACFT OFF THE ROAD, CONTACT WAS AGAIN MADE WITH ATC VIA A HANDHELD RADIO AND A CIRCLING PIPER CHEROKEE (ACFT Y) ABOVE. ATC WAS INFORMED OF MY LOCATION AND NO INJURY STATUS. ATC INFORMED ME THAT EMER FIRE AND RESCUE AND STATE POLICE WERE INFORMED. VISUAL INSPECTION OF THE WING TANKS BY ME AND PERSON X. EMER SVCS CONCLUDED THERE WAS NO VISIBLE FUEL ON BOARD. EMER SVCS PROVIDED ME WITH 11 GALLONS OF 100LL. THE WINGTIP WAS EXAMINED BY ME (CERTIFIED A&P), PREFLT CONDUCTED, SYS CHKED AND THE ACFT WAS DETERMINED TO BE AIRWORTHY BY ME. WITH THE KNOWLEDGE AND CONSENT OF ALL AUTHS INVOLVED, I FLEW THE ACFT VFR FROM THIS LOCATION TO ZZZ2. I ANTICIPATED CLOSER TO 10 GPH FUEL BURN VERSUS THE 13 GPH FUEL BURN EXPERIENCED. PLT ERROR ASIDE, FROM A RISK MGMNT PERSPECTIVE, POSSIBLE MITIGATING CIRCUMSTANCES INCLUDE: A FUEL VENTING ISSUE OF SOME TYPE AND/OR EXCESSIVE HIGH/RICH FUEL CONSUMPTION, INACCURATE EGT, AND/OR IMPROPER CONSIDERATION THAT TANKS ARE FULL EVEN IF FUEL IS NOT RUNNING OUT OF THE TOP OF THE WING BEFORE FUEL CAPS ARE INSTALLED. NO MATTER THE EDUCATION, CERTIFICATES AND EXPERIENCES, THIS CAN HAPPEN TO ANYONE. REGARDLESS OF FUEL VENTING ISSUES, EXCESSIVE FUEL BURN, INACCURATE EGT OR OTHER POSSIBLE MITIGATING FACTORS, DON'T RELY EXCLUSIVELY ON ARITHMETIC, CHARTS AND GRAPHS. IF THE FUEL GAUGES SAY EMPTY -- LAND! IF YOU DON'T, PREPARE TO BE EMBARRASSED, HUMILIATED AND HUMBLED BY THIS SOBERING EXPERIENCE.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.