Windshear event involving a Cessna 172N, VH-FMH, Mount Hogan, Queensland, on 26 May 1993

The aircraft was loaded to near the maximum permissible all up weight for the takeoff from the 1,000m strip which is 1,950ft above mean sea level. The strip is surrounded by low rolling hills which rise some 200 to 300 ft above the height of the strip.

The aircraft took off in the 040 degree direction, becoming airborne about half way along the strip. Flap 10 (degrees) had been selected for the take-off and was retracted once the aircraft was safely airborne. The pilot adopted the best climb attitude which held 60 knots. Initially the climb rate was 500ft per minute, but when the aircraft entered mild mechanical turbulence, this changed to a 300ft per minute descent rate. This situation continued until impact with trees on a ridge line some 1,000m beyond the departure end of the strip. The occupants were not injured and vacated the wreckage without assistance.

At the time of the accident the wind direction and strength was judged to be 060 degrees at 15 knots.

It is most probable that the aircraft encountered a downdraft in the lee of the hills to the north-east of the strip which negated the climb performance of the aircraft.