Incident Overview
On August 26, 2018, at approximately 11:36 local time, a Cirrus Aircraft SR22 registered as N4927 was involved in a serious incident while flying under Visual Flight Rules (VFR). The aircraft was operating a private flight from Samedan (LSZS) to Elba (LIRJ), Italy. At the time of the event, the aircraft was at an altitude of approximately 3,600 meters (12,000 ft AMSL) over the Maloja Pass.
Operational Context
The pilot, a Swiss national holding a Commercial Pilot Licence (CPL(A)), was accompanied by two passengers. Prior to the incident flight, the pilot had flown from Lugano to Samedan to pick up the passengers. The weather conditions in both the Engadin and Ticino regions were nearly cloudless with good visibility.
Sequence of Events
Eleven minutes after takeoff, while crossing the Maloja Pass, the crew experienced sudden vibrations. The pilot performed a quick check of the engine parameters, which remained within normal limits, and noted that the vibrations decreased at lower airspeeds. Suspecting an engine issue, the pilot notified Milano Information and decided to divert to Lugano (LSZA), where the aircraft was based. The diversion flight lasted 30 minutes and concluded with an uneventful landing.
Investigation Findings
Upon inspection after landing, it was discovered that a portion of the left plastic gear fairing had broken off. A subsequent check-flight conducted two days later with the fairing secured showed no further vibrations or anomalies. The Swiss Transportation Safety Investigation Board (STSB) concluded that the vibrations were most likely caused by the loss of the fairing component. While the exact cause of the structural failure could not be definitively determined, fatigue weakening of the plastic part was considered a plausible factor.