On February 16, 2003, about 1430 eastern standard time, a Cessna
140, N76897, was substantially damaged during a forced landing
to a field near Fryeburg, Maine. The certified flight instructor
(CFI) and the private pilot were not injured. Visual
meteorological conditions prevailed for the flight that departed
Eastern Slopes Regional Airport (IZG), Fryeburg, Maine, about
1400. No flight plan was filed for the local instructional
flight conducted under 14 CFR Part 91.  The private pilot stated
that he had recently purchased the airplane, and was receiving
flight instruction. The private pilot completed some maneuvers
at an altitude of 2,500-3,000 feet msl, and about 1430, the CFI
applied carburetor heat while setting the engine power to idle
for a simulated engine failure.  The private pilot completed the
emergency checklist items, and positioned the airplane for a
simulated forced landing to a field. During the descent, the
carburetor heat remained on, and the CFI occasionally cycled the
throttle to "clear the