Incident Overview
On December 29, 2015, a Cessna 172RG aircraft, registration G-CHZI, operated by Omni Aviation Training Center, was involved in a serious incident during a training flight at Cascais Airport (LPCS). The aircraft sustained substantial damage after a main landing gear actuator failure led to a runway excursion upon landing.
Flight History
The aircraft departed Cascais at 09:45 UTC with an instructor pilot and a student pilot on board for an instrument instruction flight to Faro (LPFR). After conducting instrument approaches at Faro, the crew performed a low pass, a standard procedure following a discontinued approach. During landing gear retraction, the position indicator showed the gear was retracted, but an unusual mechanical noise was heard. The flight continued as planned, and later a new approach was made using the ILS for runway 10. When the landing gear was extended, the position indicator did not show the gear down and locked. The instructor pilot confirmed that the right main landing gear wheel was not in its normal position.
The instructor pilot decided to continue the approach but retracted the gear and performed another low pass. The air traffic controller (ATC) noticed the abnormal position of the right main gear leg and informed the crew. The crew then decided to return to Cascais with the gear anomaly.
Emergency Landing
Before landing at Cascais, the crew executed the manual landing gear extension checklist using the emergency hand pump. However, the position indicator still did not show the gear down and locked. A low pass was performed for ATC to confirm the anomaly. The crew then left the circuit and attempted unsuccessfully to lock the gear in the extended position.
At 12:58 UTC, the crew decided to perform an emergency landing on runway 17 with the gear down but not locked. The aircraft intentionally touched down slightly left of the runway centerline, initially with the left main gear, followed by the nose gear. After the right main gear wheel, which was not locked, contacted the ground, the aircraft began a rotation to the right and came to rest at approximately 80 degrees to the runway heading.
Damage and Injuries
The crew evacuated the aircraft unharmed. The aircraft sustained damage to the landing gear, the lower area of the rear fuselage, the right wing tip, and the right stabilizer and elevator.
Meteorological Conditions
ATC reported wind from 180 degrees at 9 knots with visibility of 10 kilometers or more at the time of landing.
Investigation
The former GPIAA (now GPIAAF) opened a safety investigation. The event was classified as a serious incident involving a system/component failure (non-powerplant) with a runway excursion.