What happened
On January 9, 2011, a Cessna 172J, registration CS-DDS, departed from Cascais Municipal Aerodrome to perform training maneuvers at Torres Vedras Municipal Aerodrome (LPSC). During the landing phase on runway 35, the aircraft experienced several bounces on the runway. In an attempt to stabilize the aircraft, the pilot pushed the control column forward, which caused the nose gear to strike the pavement with significant force. This impact fractured the nose gear support structure and caused the propeller blades to strike the asphalt, resulting in engine stoppage. The pilot managed to steer the aircraft to the left, eventually coming to a halt on the unpaved area adjacent to the taxiway. There were no injuries to the pilot.
The investigation
The GPIAAF investigation examined the environmental conditions, the pilot's flight profile, and the mechanical failure of the landing gear. Investigators analyzed meteorological data from the Torres Vedras station, which indicated that while winds were generally light, there were significant fluctuations and rapid changes in wind speed during the afternoon. The investigation also reviewed the pilot's flight experience and the structural design of the Cessna 172J nose gear, noting that the component is not designed to withstand high-impact landings.
Findings
- The pilot conducted the approach with a descent angle of less than 3 degrees, utilizing power and approach speeds slightly higher than recommended.
- The aircraft was affected by windshear during the flare phase; an initial updraft caused the aircraft to rise, followed by a downdraft that pushed the aircraft toward the runway.
- The pilot's instinctive reaction to push the control column forward to keep the nose down exacerbated the impact of the downdraft, leading to the nose gear fracture.
- The pilot had not flown for more than three months prior to the incident, which served as a contributing factor in the inability to manage the sudden atmospheric changes.
- Local environmental factors, including the proximity to the coast and nearby greenhouses, contributed to the presence of both dynamic and convective windshear at the aerodrome.