Synopsis
On 02.10.2024 at approximately 16:00 local time, a Savannah S aircraft registered YR-5602, owned and operated by Aeroclubul României, was conducting a training flight for precision landings at Gheorghe Valentin Bibescu Aerodrome (ICAO: LRPW) in Ploiești, Prahova county, Romania. After landing on runway 07, during taxiing, the crew noticed a tendency of the aircraft to move left of the runway centerline accompanied by a loud noise. They interrupted essential contacts, including fuel supply, stopped the aircraft on the runway, and evacuated. Post-evacuation inspection revealed the left main landing gear wheel was missing. The aircraft suffered no other damage, and the crew did not require medical assistance.
Flight History
The flight was a training exercise for precision landings. After touchdown, while taxiing, the crew perceived an abnormal movement and noise. Initially suspecting a tire puncture, they requested technical assistance. The crew shut down the aircraft and evacuated safely. The technical team removed the aircraft from the runway.
Aircraft and Crew Information
The Savannah S, manufactured by ICP LLC Italy, is an ultralight powered aircraft with a high wing, side-by-side seats, and a Rotax 912 ULS engine. It had accumulated 1612 flight hours and 8651 landings at the time of the event. The landing gear is tricycle type with a steerable nose wheel and main gear shock absorption via an aluminum alloy leaf spring.
The instructor pilot (male, 32) held valid licenses and had 370 total flight hours (126 on type). The student pilot (female, 25) also held valid credentials with 600 total hours (224 on ultralight).
Weather and Aerodrome
Weather from the nearest station (Henri Coandă International Airport, 40.5 km SSE) at the event time: wind variable at 3 kt, CAVOK, temperature 21°C, pressure 1013 mb. The aerodrome has an asphalt runway 075°-255°, 750x30 m.
Analysis and Cause
The left main landing gear wheel axle was sent for metallographic examination. The fracture surface showed characteristics typical of fatigue fracture, with stress almost exclusively bending from repeated loads. The slow fracture surface constituted about 20%, and the sudden fracture surface 80%. Surface damage on the axle was consistent with impacts from landings with high load factors, likely due to the precision landing training involving harder contacts. The investigation committee concluded that over more than 8600 landings, the aircraft was operated close to or at maximum permissible mechanical stresses, leading to stress concentrators and eventual fracture.
The cause was determined as the breaking of the left main landing gear wheel axle as a result of fatigue stress during aircraft operation. No safety recommendations were issued.