What happened
On February 1, 2022, a Ryanair Sun S.A. Boeing 737-800, registration SP-RSB, was performing a scheduled flight from Cologne (EDDK) to Krakow (EPKT). During the approach, the crew received ATIS information indicating that runway 27 was 100% wet with a 2 mm layer of accumulated snow. The weather was characterized by heavy snowfall, mist, and low visibility, with temperatures at 0°C.
Despite receiving an updated braking action report of 4/4/4 (indicating braking, deceleration, and directional control were between good and medium), the crew maintained their landing configuration with flaps 30 and autobrake level 3. After landing at 22:55 UTC, the crew utilized speedbrakes and thrust reversers. However, as the aircraft decelerated, the crew deactivated the autobrake system at approximately 60 knots and moved the thrust reversers to idle before reaching a safe speed.
As the aircraft approached the end of the runway, the Runway Awareness and Advisory System (RAAS) issued alerts. The captain attempted to use rudder pedals to brake the aircraft approximately 70 meters before the runway end, and later reapplied thrust reversers when no response was noted. Ultimately, the aircraft crossed the runway end lights at a ground speed of 11.5 knots, skidded, and veered 45 degrees left. The main gear remained on the asphalt, but the nose gear ended up on the grass, approximately 5 meters from the runway edge. No injuries were reported, and no damage to the aircraft was found upon inspection.
The investigation
The investigation examined the crew's performance, the aircraft's systems, and the environmental conditions. The investigation established that while the initial landing and deceleration phases followed standard procedures, the crew's actions during the later stages of the rollout deviated from Standard Operating Procedures (SOP). Specifically, the investigation looked into the deactivation of braking systems and the crew's response to RAAS alerts.
Findings
- The crew experienced a state of relaxation following the successful completion of the landing phase in difficult weather.
- The crew maintained a ground speed greater than 5 knots during taxiing on a contaminated and slippery runway, which was contrary to SOP.
- The deactivation of the autobrake and speedbrake systems occurred without certainty that the remaining runway length was sufficient to stop the aircraft.
- The crew failed to respond appropriately to the RAAS warnings regarding the approaching runway end.
- Operational conditions on the final portion of the runway were worse than the crew had anticipated.
- Contributing factors included rapidly changing meteorological conditions and failure to adhere to SOPs regarding thrust reverser usage and speed management on contaminated surfaces.
Safety action
- Supplemental simulator training involving winter operation scenarios has been completed for both pilots.
- A line check has been conducted to verify the qualifications of both pilots.