What happened
On April 25, 1962, a Swissair SE-210 Caravelle III, registration HB-ICT, departed Geneva for Paris. Shortly after takeoff, the flight crew attempted to retract the landing gear, but the nose gear became stuck in a partially extended position. The cockpit warning lights indicated that the gear doors had not fully closed and locked.
Due to the mechanical malfunction, the flight was diverted to Zurich-Kloten. After consuming excess fuel and preparing for an emergency arrival, the aircraft performed an emergency landing on Runway 16 at 09:56 local time. The pilot utilized a foam carpet on the runway to assist the landing. During the deceleration, the nose of the aircraft made contact with the runway, causing significant damage to the fuselage nose. Despite the impact and a small fire that broke out under the flight deck, all 66 passengers and 6 crew members escaped without injury.
The investigation
SUST investigators examined the nose gear mechanism and the maintenance history of the aircraft. The investigation focused on the state of the landing gear doors and the sequence of events in the Geneva hangar the previous evening. Investigators also reviewed the maintenance logs and the specific procedures for K-Checks and V-Checks performed by the ground crew.
Findings
- The primary cause of the nose gear blockage was an unauthorized intervention in the gear door mechanism by a member of the maintenance staff for non-operational purposes the night before the accident.
- The maintenance supervisor opened the gear door control mechanisms to facilitate a student's photographic study of the nose gear and failed to close or secure them properly afterward.
- The error went unnoticed during the subsequent K-Check and V-Check inspections, as the maintenance mechanic and the co-pilot did not identify the abnormal position of the gear doors.
- A mechanic noticed the door was open while the engines were running but, being unfamiliar with the specific mechanism, incorrectly assumed the doors would close automatically during retraction.
- The aircraft sustained heavy damage to the nose section, requiring approximately 16,000 man-hours for repairs.