Incident Overview
On 12 November 2019, a scheduled Ryanair Sun S.A. flight from Krakow Airport (EPKK) to Lamezia Terme Airport (LICJ) encountered a technical issue shortly after departure. The aircraft involved was a Boeing 737-8AS bearing registration SP-RSA.
Flight Details and Crew Actions
Immediately after takeoff, the pilot monitoring performed the landing gear retraction procedure, but the gear did not retract and remained in the down position. The flight crew decided to continue the climb according to the standard instrument departure (SID) while notifying air traffic control (ATC) about the inability to retract the landing gear. ATC authorized the aircraft to level off at 6,000 feet and directed it to a holding area. The crew then executed the "GEAR DISAGREE" procedure from the Quick Reference Handbook (QRH). Following the procedure, they decided to abort the flight to the destination and return to the departure airport. The aircraft landed at Krakow without further incident. Post-flight inspection revealed no damage to the airframe or landing gear. A test of the Proximity Switch Electronic Unit (PSEU) showed no faults in the systems monitoring aircraft configuration. The investigation found no errors or procedural lapses by the flight crew.
Investigation Findings
The aircraft operator subsequently replaced the "Landing gear lever module and manual extension system access door switch" subassembly. The investigation, conducted by the Polish State Commission on Aircraft Accident Investigation (PKBWL), determined that the likely cause of the incident was a malfunction of that specific subassembly. No contributing factors were identified.
Probable Cause
The probable cause of the incident was a malfunction of the landing gear lever module and manual extension system access door switch.
Preventive Actions
The operator considered the incident an isolated occurrence and recommended monitoring any future issues related to the replaced component. No other preventive measures were required.