On May 20, 1996, at 1320 central daylight time, a Piper PA-23-150, N299MD, was substantially damaged during a forced landing near Paradise, Texas. The airplane was registered to a private owner and operated by Pro Aircraft of Fort Worth, Texas, as a Title 14 CFR Part 91 flight. The commercial pilot/flight instructor and a passenger were not injured. The private pilot/multiengine student received minor injuries. The flight originated from Hicks Airfield at 1245. Visual meteorological conditions prevailed for the instructional flight and a flight plan was not filed. In his written statement to the NTSB, and during a telephone interview, conducted by the investigator-in-charge, the pilot reported the following information. The twin engine airplane was maneuvering at 4,500 MSL for single engine training. The flight instructor secured and feathered the left engine to demonstrate single engine flight procedures and performance. About 30 to 35 seconds after securing the engine, the flight instructor elected to restart the engine; however, after several attempts to restart, the left engine did not restart. The flight was near Bridgeport, Texas; however, with a headwind (winds from 240 degrees at 20 to 30 knots) toward Bridgeport the instructor made a decision to divert to Decatur, Texas. Subsequently, the right engine began showing a power loss with a manifold pressure decrease from 25 inches to 19 inches. The pilot reported that the landing gear began to "creep down" and the hydraulic hand pump was utilized; however, using the hand pump did not fully retract the gear and it continued to "creep" down. The pilot further reported that the altitude was 1,700 feet MSL when he realized that the flight would not make Bridgeport or Decatur. With the airplane approximately 300 feet AGL, a final approach was established for the forced landing to the field with a gravel pit. The pilot concentrated on maintaining control of the airplane and emergency extension of the gear was not performed; however, the landing gear was partially extended at the time of landing. Examination of the airplane by the FAA inspector revealed structural damage to the engine mounts, wings, and landing gear. According to the airplane operator's manual, the hydraulic system used to extend the landing gear is driven by the left engine. With the gear selector in the "UP" or "DOWN" position, the hand pump is used to retract or extend the landing gear in the event of a hydraulic failure. The reason for the loss of the right engine power and the hydraulic pressure loss was not determined.