On January 27, 2018, about 1615 eastern standard time, a Piper PA-28-140, N9673W, was substantially damaged during a forced landing while approaching Meriden Markham Municipal Airport (MMK), Meriden, Connecticut. The airline transport pilot and one passenger were seriously injured. The airplane was operated by the pilot under the provisions of 14 Code of Federal Regulations part 91 as a personal flight. Day, visual meteorological conditions prevailed, and no flight plan was filed for flight that originated at Oxford County Regional Airport (81B), Oxford, Maine about 1330. The pilot reported that he performed the preflight inspection at 81B and determined that there were 36 gallons of fuel on board prior to departure. Earlier that day, his passenger flew the airplane from MMK to 81B and reportedly departed MMK with full tanks, or 50 gallons of fuel on board. The airplane was not refueled at 81B. For the flight from 81B to MMK, his flight planning showed that he would land with 6 gallons of fuel on board. Just prior to passing Worcester, Massachusetts, while on the right tank, the fuel gauge began to "flicker," then the engine "faltered." He intentionally exhausted the right tank fuel supply to maximize his available fuel. He switched to the left tank and the flight continued. Approaching the Hartford, Connecticut area, his passenger suggested that they stop for fuel, but he was confident in his fuel calculations and did not want to pay a higher price for fuel there, so he continued. About 2.5 miles north of MMK, the fuel pressure gauge "faltered" and the engine subsequently lost power. He looked for a place to land and realized that a nearby pond would be the best option. During the forced landing attempt, the airplane collided with a fence and came to a stop on dry land. An inspector with the Federal Aviation Administration responded to the accident site and examined the wreckage. The airplane came to rest on an embankment after colliding with a chain link fence. Both wings and the lower, forward fuselage was structurally damaged. The nose gear snapped off during the impact sequence and was found under the airframe. The left and right wing fuel tanks were not compromised. The airplane was moved to a level position and no visible fuel was observed in either fuel tank. During the subsequent recovery of the wreckage, about 1/2 gallon of fuel was recovered from both tanks. No fuel stains were observed on the exterior surfaces of the airframe. The pilot reported on the NTSB Form 6120.1, Pilot/Operator Aircraft Accident Report, that there was no mechanical malfunction or failure prior to the accident. In a subsequent correspondence with the NTSB investigator-in-charge, the pilot reported that there was a leak at the gascolator found on November 17, 2017. The gascolator gasket had slipped out of place, resulting in the leak. He found the gascolator components to be in good condition and he reassembled the unit. The airplane was then flown at least 10 hours without any observed leaks prior to the accident flight. On March 26, 2018, the gascolator was removed from the wreckage and examined by a NTSB investigator. The unit was intact, and no evidence of obstructions, leaks or fuel staining was found.