On December 23, 2003, at 1105 eastern standard time, a Piper PA-44, N432PA, was substantially damaged during a forced landing near Prospect, Pennsylvania. The certificated flight instructor and the certificated private pilot (multi-engine student) were seriously injured. Visual meteorological conditions prevailed, and no flight plan had been filed. The local instructional flight, which originated at Beaver County Airport (BVI), Beaver Falls, Pennsylvania, was conducted under 14 CFR Part 91. In an interview, the flight instructor stated that he had planned to demonstrate single engine maneuvers including Vmc and drag characteristics, engine shutdown and restart, and several single engine approaches to full stop landings. After takeoff, the airplane proceeded to a practice area, where ground elevation varied between 1,000 and 1,200 feet above mean sea level (msl). At an altitude between 3,000 and 3,500 feet msl, the flight instructor reduced power on the right engine to a zero-thrust setting, and maintained that setting for 4 to 5 minutes. The flight instructor and the student then shut down the engine, and feathered the propeller. After performing single engine maneuvers for another 5 minutes, the student attempted to restart of the right engine "per the published procedure," including unfeathering the propeller, but the restart was unsuccessful. The flight instructor then noticed that the airplane had descended to an altitude of 2,500 feet msl, so he had the student fly the airplane while he attempted to restart the windmilling engine. Initially, the airplane's descent airspeed was 88 knots (Vyse); however, the airplane was subsequently slowed to 82 knots (Vxse) in an attempt to arrest the descent. At 1,700 feet msl, the flight instructor began flying the airplane, and told the student that they were going to land in a field below. As the flight instructor approached the field, he deployed the landing gear, and set 25 degrees of flaps. While on the short-final leg of the approach, the airplane hit the tops of some trees bordering the field. The instructor lost consciousness, and awoke with the airplane on the ground. He then secured the airplane, made sure his student was conscious, and left to seek help. Also during the interview, the instructor noted that, while performing the ground run-up of the left engine, there was a 175-rpm drop during the magneto check. The instructor "cleared the plugs" by running the engine with a lean mixture. He then tested the magneto again and observed a 100-rpm drop. During the subsequent takeoff, all engine indications were normal. Inspection of the left and right engines revealed no mechanical anomalies. A review of the flight instructor's logbook revealed that he had received his multi-engine flight instructor rating on July 5, 2003, and that he began training his first multi-engine student on November 2, 2003. Prior to the accident, the flight instructor had accumulated 49.6 total hours of experience in multi-engine airplanes and 4.8 hours of multi-engine instructing experience. According to Federal Aviation Administration (FAA) inspectors, the area where the airplane made the forced landing was a small clearing next to a larger pasture, with 75-foot trees about 2/3 of the way around it. The airplane impacted rising terrain on a 40-foot hill, with a 30-degree up slope. The weather reported at Butler County Airport/K W Scholter Field (BTP), Butler, Pennsylvania, located about 9 nautical miles southeast of the accident site, at 1055, included winds from 210 degrees true at 5 knots, 10 statute miles visibility, few clouds at 2,900 feet, temperature 52 degrees Fahrenheit, dew point 40 degrees Fahrenheit, and a barometric pressure of 29.86 inches of mercury. According to the Piper PA-44 information manual, intentional one-engine operations should not be performed at an altitude of less than 4,000 feet above the ground. According to the "Climb Performance - One Engine Operating" chart, with a temperature of 52 degrees Fahrenheit on the surface, a pressure altitude of 2,000 feet, a gross weight of 3,670 pounds, at an airspeed of 88 knots, and in a clean configuration with the inoperative engine's propeller feathered, the airplane should have been able to attain a 180 feet per minute (fpm) climb rate. The information manual additionally stated that with the one propeller windmilling, and the landing gear and flaps in the retracted position, the airplane would have incurred a -200 fpm climb performance penalty.