The Australian Transport Safety Bureau did not conduct an
on-scene investigation of this occurrence.
REPORTED INFORMATION
At about 1610 central standard time on 18 April 2005 the pilot
of a Cessna Aircraft Company Cutlass, registration VH-LCZ commenced
the takeoff at Warooka Aeroplane Landing Area (ALA), SA. The
private flight, with one pilot and two passengers, was the last of
a number of planned flights that day from Warooka to Wedge Island
ALA. The pilot estimated that his aircraft was about 10 kg (22 lbs)
below the maximum allowable take-off weight for the aircraft. The
aircrafts centre of gravity (c.g.) was not reported.
The pilot elected to take off towards the south, which resulted
in a right crosswind that he described as `steady, but with a bit
of swing to it. The pilot indicated that the take-off run to the
south was `normal, and that he lifted the aircraft off from the
runway at 60 kts indicated airspeed (KIAS) with the intent of
establishing the climb at the aircraft best angle of climb speed of
67 KIAS. That was in order to avoid a house and powerlines at the
southern end of the airstrip.
As the aircraft became airborne the pilot retracted the landing
gear, which swings downward approximately 2 ft as it starts
retracting. The pilot reported that almost immediately, the
aircrafts stall warning unit activated. In response, he `lowered
the nose of the aircraft towards the cruise attitude. The aircraft
lost height and impacted the ground and subsequently slid to a stop
on its belly. The occupants were not injured. The aircraft was
substantially damaged.
The aircrafts Information Manual (manual) stated that the wing
flaps should be set at zero degrees for normal takeoffs, and that
the landing gear should not be retracted unless there was
insufficient remaining runway to allow a wheels-down forced
landing. In addition, the manual included that the aircrafts stall
warning unit provides a continuous warning tone to the pilot at 5
to 10 kts above the aircrafts stall speed. With zero flap, and at
zero angle of bank and maximum takeoff weight, that speed was 46
KIAS at the most rearward c.g. and 50 KIAS at the most forward
c.g.
ATSB COMMENT
Given the reported take-off weight and nature of the load, it
was likely that the aircrafts centre of gravity approached the
rearward limit. In that case, a takeoff conducted in the normal
take-off configuration would have meant that the stall warning unit
would most likely have activated in between 51 to 56 kts indicated
airspeed (KIAS).
The safety margin between the lift-off speed and the stall speed
may have been eroded by the effect of any `swing in the wind during
the retraction of the landing gear, and the potential for any
increase in drag associated with the retraction of that gear. The
relative proximity of the aircraft to the ground when the stall
warning unit activated minimised the possibility for the pilot to
recover the aircraft before it impacted the ground.