Air carrier flight crew reported after landing and taxing on the runway encountering surface conditions worse than reported resulting in the flight crew losing control of the aircraft. The flight crew was able to regain control of the aircraft and taxi to the gate.
Synopsis
Air carrier flight crew reported after landing and taxing on the runway encountering surface conditions worse than reported resulting in the flight crew losing control of the aircraft. The flight crew was able to regain control of the aircraft and taxi to the gate.
Narrative
This is only for the landing roll out on Runway 31 in DSM. The Tower reported to us that braking action was good for landing on Runway 31. What we experienced was completely different. There were a few taxiway closures and snowplow operations at the airport. The landing and initial rollout were normal. The Tower asked us to roll to the end and report when clear of the runway. I was taxing with caution because the runway was covered in snow and what I perceived to be ice. I also noticed it was more slippery than reported. By the time we got to the end for turn off braking had definitely degraded to poor and maybe nil; in my opinion. As I was applying brakes to turn the plane it would not stop and simply slid forward. I became very concerned that we would slide off the end of the runway. Although we were below reverse speed; in an effort to safely stop the aircraft from sliding off; I deployed the thrust reversers. Without them I feel we would not have been able to stop before the end of the runway. We were able to safely stop the aircraft and taxi off the runway in the normal taxi route. Also the taxiways to the gate were very slippery and braking action was poor.
Second reporter narrative
Airport RCC (Runway Condition Code) was NOTAM'd 3/3/3. Only runway exit cleared was the D6 at the end of the runway. Upon touchdown braking wasn't horrible I'd say even slightly better then RCC3 however it significantly worsened towards the last 1/4 of the runway. As the Captain began to further brake for the exit at the end the aircraft immediately started sliding and we nearly ran off the end of the runway. Without bringing the reversers out we absolutely would have. I informed Tower the braking action was non existent the last 1/4 of the runway and it needed to be addressed or even have an earlier exit cleared to prevent the aircraft behind us from running off the end of the runway. We updated Tower letting them know the taxiway also needed to be plowed again as we were sliding despite the plows having just made a pass.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.