What happened
On 15 July 1956, an aircraft operating as a delivery flight for Swissair was en route from New York to Zurich via Gander and Shannon. The crew of four, consisting of two American pilots, had departed Gander earlier that evening. Upon reaching the vicinity of Shannon Airport at approximately 00:08 hours, the flight was cleared for an initial descent and entered a holding pattern alongside several other aircraft.
At 01:25 hours, the crew began a Ground Controlled Approach toward runway 23. As they established visual contact with the ground, the flight transitioned into a left-hand visual circuit to align with runway 05. During the turn onto the final approach for runway 05, the aircraft entered a steep bank and was observed to lose altitude rapidly. The aircraft struck the ground at roughly 01:35 hours, resulting in the destruction of the airframe and 4 fatalities. There was no post-impact fire.
Findings
Investigations into the crash identified that an error of judgment by the pilot led to an excessively steep turn during the approach, causing the aircraft to slip into the terrain. Several contributing elements were noted, including the lack of sufficient visual landmarks on the ground due to the darkness of the night. Additionally, investigators considered that the crew's proficiency may have been compromised by the extended duration of their duty period.