A Staaken Z-21 Flitzer homebuilt biplane was on approach to RAF Lossiemouth’s Rwy 05, its pilot believing from looking at the windsock, that the surface wind was...
A Staaken Z-21 Flitzer homebuilt biplane was on approach to RAF Lossiemouth’s Rwy 05, its pilot believing from looking at the windsock, that the surface wind was 340�/10-12kt, implying a crosswind from the left of some 11kt. He made his approach port wing low and with 5kt added to the normal approach speed.
The left wheel touched down and the pilot closed the throttle and maintained port aileron to slow the rate at which the rightwing lowered. He also kept some right rudder applied to keep the aircraft straight. As the starboard wing and the tail lowered to the ground, he centralised the rudder but the port wing rose rapidly, accompanied by a marked swing to the right. The tail also began to rise. Despite the application of full left aileron and rudder, the Flitzer continued to turn right and the pilot applied some power to regain rudder authority.
The aircraft then began to swing to the left and the starboard wingtip hit the ground. After about 80� of turn it pitched forwards and became inverted. The Flitzer suffered a broken propeller, shock-loaded engine, buckled wheel, scuffing of upper wing’s covering over ribs, and upper fin and rudder crushed.
The pilot believes that the position of his left leg with right rudder applied prevented him from applying full left aileron. It also seems likely that a gust of wind lifted the port wing at a rate that was beyond the roll authority available. Although full left rudder input physically allowed the application of full left aileron, the pilot was unable to control the subsequent motion of the aircraft.