What happened
On January 11, 2008, a CANADAIR – CL-600, registration N-601JM, operated by Airborne Express Inc., was performing a flight from Budapest to Milan. Shortly after takeoff from Budapest Ferihegy, during the landing gear retraction phase, the aircraft experienced a malfunction where the landing gear failed to retract. Due to this technical irregularity, the crew performed a turnaround and returned to Budapest Ferihegy, where the aircraft landed safely.
The investigation
The investigation conducted by the KBSZ determined that the failure to retract the gear was caused by a malfunction in the left landing gear proximity sensor, which is responsible for controlling the landing gear retraction sequence. Upon inspection, the operator's maintenance personnel cleaned the sensor and performed a landing gear retraction test; however, the test was unsuccessful, and the central error display unit indicated a sensor fault. The issue was resolved the following day after a replacement sensor was brought in from Vienna and installed, after which the aircraft returned to service.