On April 20, 2001, about 1300 central daylight time, an experimental homebuilt Christen Eagle II, N181DM, registered to a private individual, operating as a Title 14 CFR Part 91 personal flight, sustained a complete loss of power and a forced landing while in cruise flight near Alexander City, Alabama. Visual meteorological conditions prevailed and no flight plan was filed. The aircraft sustained substantial damage and the ATP-rated pilot, the sole occupant, was not injured. The flight originated from Ball Ground, Georgia, for Maxwell Field, Montgomery, Alabama, about 50 minutes before the accident. According to the pilot, he and another Eagle were in loose formation cruise flight at 4,500 feet msl, about 14 NM east of Alexander City when his engine quit without any warning. He was trying for an emergency landing to an open field surrounded by a forest when his propeller caught a tree canopy, causing a loss of flare speed and a hard touchdown in the field. According to an FAA inspector, during the emergency landing, the aircraft touched down in a clear pasture in the middle of a wooded area, and flipped over. Adequate fuel remained in the fuel tank, and issues of fuel depletion, weather, and pilot skills were dismissed. The FAA inspector requested the pilot submit a "Malfunction or Defect Report" if applicable, at a later date. The pilot removed the fuel injector servo, a modified Bendix RSA-5AD1, serial no. 35088, known as the "2 stage SPL MOD" done by Airflow Performance, Inc., and sent it to the NTSB for further examination. Repair station disassembly examination, overseen by the NTSB, revealed the fuel injector's regulator diaphragm stem nut had completely backed off the threaded portion of the regulator stem, and was lying loose inside the regulator chamber. No evidence of "Loctite" or other similar product was found on the stem threads or the stem nut, nor was evidence of any other method of locking the stem nut in place found. Photographs were taken by the NTSB, and are an attachment to this report. Although the fuel injector servo modifying facility or the procedures used in the modification do not need FAA certification or approval due to the aircraft's experimental category, the following excerpt from the fuel servo manufacturer's component maintenance manual is referenced, "When final calibration, [of servo fuel injector assembly] is complete, check to see that at least two full threads are visible above self locking nut. Apply a light film of Loctite to the threads above lock-nut, as shown in Figure 104, with Loctite applicator 2550982."