On February 16, 2013, about 2145 central standard time, a Cessna model 195 airplane, N4426C, was substantially damaged while taxiing at the Austin Executive Airport (EDC), Austin, Texas. The private pilot and passenger were not injured. The airplane was registered to and operated by the pilot, under the provisions of 14 Code of Federal Regulations Part 91, without a flight plan. Night visual meteorological conditions prevailed for the personal flight. The flight had the intended destination of Gillespie County Airport (T82), Fredericksburg, Texas.The pilot reported that the accident occurred as he was taxiing on the unlit taxiway that paralleled runway 13-31. As the airplane approached the end of the taxiway, adjacent to the runway 13 threshold, the right wing landing light became inoperable, significantly reducing the pilot's forward visibility in the dark night conditions. The pilot cycled the right wing landing light switch as he applied wheel brakes; however, the light did not illuminate. The pilot stated that he was unable to stop the airplane before it departed the end of the taxiway and traveled down an embankment. He did not recall seeing any reflective markers identifying the end of the taxiway. Although the airplane was equipped with two landing lights, one on each wing, the pilot reported that he avoided using both lights simultaneously during taxi operations because such use rapidly depletes the battery charge at the lower engine power settings required to taxi. According to information provided by the EDC airport manager, the unlit taxiway that serviced runway 13-31 was marked with blue reflective posts that were 24-inches tall. These blue reflective posts were spaced at 31-foot intervals along the taxiway edges only. The end of the taxiway was identified by red reflectors that were installed at ground level. Additionally, an airport survey plot indicated that there was a 16-foot descending embankment, specified to have a 3:1 graded slope, located immediately adjacent to the northwest end of the taxiway and the runway 13 threshold. The use of reflective posts to identify the taxiway and the descending embankment were not identified in the Federal Aviation Administration (FAA) Airport Facility Directory. According to the FAA Airplane Flying Handbook, the requirements for safe taxi operations include the ability to recognize potential hazards in time to avoid them, as well as the ability to stop or turn where and when desired. The handbook further stipulates that taxi speeds should be slow enough that the airplane can be stopped promptly and "without undue reliance on the brakes." At 2155, the airport's automated surface observing system reported: wind 210 degrees true at 4 knots, visibility 10 miles, sky clear, temperature 8 degrees Celsius, dew point -3 degrees Celsius, and an altimeter setting 30.24 inches of mercury. The United States Naval Observatory reported that sunset and end of civil twilight at the airport on the night of the accident occurred at 1820 and 1844, respectively. At 2145, the waxing crescent moon was visible to the west of airport, located about 36 degrees above the horizon, with about 44 percent of the moon's visible disk illuminated. The moonset occurred about 3 hours after the accident at 0046. In response to the accident, the airport authority agreed to purchase additional blue reflective posts to more adequately mark the limits of the unlit taxiway. Additionally, the FAA agreed to amend its Airport Facility Directory to reflect that the taxiway edges were marked by reflector posts and that the northwest end of runway 13-31 and parallel taxiway had a 16-foot descending embankment beginning at the end of the pavement.