Undershoot after full flaps set by observer
PUBLISHED: 11:16 23 June 2011 | UPDATED: 14:04 10 October 2012
A Scintex CP301-C2 had undergone an extensive rebuild and a flight test was planned in order to obtain a PFA Permit renewal.
A Scintex CP301-C2 had undergone an extensive rebuild and a flight test was planned in order to obtain a PFA Permit renewal. The handling pilot, the aircraft owner, was accompanied by the PFA Inspector who acted as the flight test observer.
Carburettor icing was experienced while on the ground but cleared normally with the application of carburettor heat. The take-off and climb were normal. In the cruise, as a precaution, carburettor heat was applied; slight carburettor icing appeared present, but cleared normally.
Stall tests were then carried out, with carburettor heat applied before the engine power was reduced. Power was then increased to around 1,800 rpm and a few gentle turns performed before recovery to Garston Farm, near Bath.
During the return a simulated baulked landing was carried out, and the descent towards it involved reduced power with carburettor heat applied. Following a height loss of some 200 feet, full power was applied and the carburettor heat was returned to 'cold' for the simulated go-around. After a brief climb of some 100 feet, the aircraft was levelled and power reduced to a cruise setting. A couple of light 'pops' were then heard which the pilot considered were consistent with ice being ingested into the engine. The engine then began to run roughly. Carburettor heat was immediately re-applied, but without apparent effect on the engine which was running at about 1,600 rpm, and would not deliver full power.
Conditions were conducive to moderate to serious carburettor icing with descent power applied.The aircraft was now four nm north of Garston Farm at around 1,800 feet agl. The pilot considered attempting a forced landing in a field but the ground in the area was soft and recently ploughed and so he elected to return to the farm strip.
The engine continued to run roughly but with indicated temperatures and pressures normal. The pilot was familiar with the airfield and set the aircraft up high on final approach as he was aware of the possible effect of sink from high trees to the south east of the airfield.
At around 300 feet the flight test observer, who was less familiar with the airfield, became concerned at the steep approach and selected full flap.
At around 200 feet the combined effect of wind shear and full flap caused a high rate of descent to develop. The propeller also stopped rotating at around 150 feet, causing additional drag. The pilot turned the aircraft to the right before landing, to avoid a low stone wall in the undershoot area, however the left wing struck a small tree causing the aircraft to yaw left before landing in soft ground beyond the tree.
Both main gears collapsed and the aircraft sustained extensive damage, but both occupants escaped injury.