Croatia Airlines Flight CTN 464 Landing Incident at Zurich Airport (9A-CQC)

Incident Overview and Aircraft Details On September 27, 2013, a Bombardier DHC-8-402 aircraft, registered as 9A-CQC and operated by Croatia Airlines under flight designation CTN 464, was involved in an accident at Zurich Airport. The incident occurred on runway 14. The aircraft was forced to land with its main landing gear extended but the nose landing gear retracted. ## Investigation Findings and Probable Cause The Swiss Transportation Safety Investigation Board (STSB) concluded that the accident was caused by the flight crew's inability to extend the nose landing gear. A contributing factor was the failure of the lower retaining devices of the weight-on-wheels (WOW) cover plate. These devices were broken and folded around the upper anchoring devices, which immobilized the nose gear mechanism and prevented its extension. ## Contributing Mechanical Factors The investigation identified two factors that contributed to the rupture of the lower retaining device. First, the installation design of the WOW cover plate generated lateral forces during nose gear steering, creating mechanical tension on both the upper and lower retaining devices. Second, imperfections were found in the weld seams in the area of the lower retaining device. ## Official Report Context The final report, numbered 2245, was issued by the Swiss Transportation Safety Investigation Board. The report states that its sole purpose is accident prevention, in accordance with international civil aviation standards and Swiss aviation law. It explicitly does not assign legal fault or liability. All times in the report are given in Coordinated Universal Time (UTC), with local time in Switzerland being UTC plus two hours at the time of the accident.