The pilot reported that while on short final approach to the runway, the airplane encountered a downdraft "that dropped the [air] plane below the glide slope." He immediately noticed a reduction in airspeed. The pilot stated that he applied power and "pulled the nose up in an effort to regain proper altitude." Subsequently, the airplane landed "very hard" and collapsed the nose wheel landing gear. Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the firewall was bent and the fuselage behind the aft seating area was buckled. The pilot reported no anomalies with the airplanes systems prior to the accident.