Flight History
On 13 October 2017 at 11:39 local time, the pilot departed from Speck-Fehraltorf airfield (LSZK) in a Cessna 172S (registration HB-TDD) for a private flight to Wangen-Lachen (LSPV). The pilot was the sole occupant. The aircraft carried 140 liters of fuel, resulting in a takeoff weight of approximately 2200 lb. A tablet computer was mounted on the control yoke.
After a short flight in good, light-wind conditions, the pilot initiated an approach to runway 26, which is 500 m long. Surface wind was from the northeast at 3 knots.
Landing Sequence
At 12:09 local time, the pilot began the final approach at 80 KIAS, then gradually reduced speed to 61 KIAS at 130 ft above ground level (AGL), as specified in the aircraft flight manual. He maintained this speed down to 50 ft AGL. At 50 ft AGL, the aircraft was 135 m before the runway threshold. The pilot noticed the tablet computer tilting downward due to insufficient fastening and reached for it with his right hand. The aircraft crossed the threshold at 20 ft AGL.
About 100 m past the threshold, the aircraft touched down hard at 55 KIAS and bounced. It then impacted the runway two more times. At 150 m past the threshold, the speed was still 53 KIAS.
After the final touchdown, the pilot applied wheel brakes. About 70 m before the runway end, at the taxiway, the ground roll speed was approximately 33 kt. The pilot exited the runway at the end, parked, and visually inspected the aircraft, noting damage to the propeller blade tips. After a pause, he started the engine, performed preflight checks, and departed from runway 08 back to Speck-Fehraltorf.
Aircraft Damage
The propeller had tip damage from ground contact. The firewall was severely deformed near the nose gear attachment. The underside of the fuselage behind the firewall was visibly compressed, and the spars and ribs in that area were damaged. Inside, the center console was displaced and the floor behind the rudder pedals was bent. The lower pivot point of the control column was displaced, restricting elevator movement.
Investigation Findings
The Swiss Transportation Safety Investigation Board (STSB) conducted a summary investigation. According to the report, the approach was stabilized until 50 ft AGL at the speed specified for maximum landing weight, but the actual landing weight was lower, resulting in an approach speed that was too high for the weight and a reduced pitch angle. The aiming point was about 90 m past the threshold, favoring a long landing. Given the 500 m runway, the pilot selected an unsuitable approach tactic. After the first hard touchdown and bounce, the pilot's elevator inputs led to a pilot-induced oscillation, culminating in a nose gear strike and propeller ground contact. The speed 150 m past the threshold was still 9 kt above the calculated takeoff speed for the weight, and delayed braking allowed the aircraft to only decelerate to taxi speed near the runway end. The pilot did not consider a go-around, which was risky due to the excess speed and late touchdown. Additionally, it was hazardous to fly back despite known propeller damage.