While cruising in level flight the engine, without warning,
commenced to vibrate severely. Engine instrumentation remained
normal and a magneto check was satisfactory. The vibration
increased rapidly to such a degree that the pilot had no
alternative but to close the throttle fully and carry out a forced
landing. The aircraft was over very rough terrain and the only
field available was 1,580 feet in length with trees to 70 feet high
at one end and to 20 feet high at the other. The approach was made
towards the taller timber, with the wheels down and half flap in a
cross wind of about 10 knots from the left. After touching down the
pilot realized that the aircraft would overrun the available area
and he immediately initiated a turn to the right. Because of the
speed and the rough surface, the aircraft skidded sideways and the
undercarriage collapsed. The aircraft performance chart indicates
that an actual distance of 1,740 feet is required to stop the
aircraft from a height of 50 feet when using full flap under the
conditions existing at the time of the landing.
