Narrative:

While in our enroute descent to cymx; we received ATIS information via ACARS. It indicated conditions as follows: -fzra broken with temperature/dewpoint of M01/M04. Runway surface condition reported as 160 ft of the 200 ft wide runway was 60% bare and wet and 40% ice. Mirabel radio provided normal tower and ground ATC communications (the field as non-tower operations). Mirabel radio advised us on final approach that after landing only B05 was available for exit (we were landing on runway 6) or we could reverse taxi on the runway to taxiway K at the approach end of runway 6. We were told the B-4 and B-6 exits were unusable. Landing and rollout were uneventful. Braking action was good. The aircraft was slowed to taxi speed by the B-5 exit point. We elected to turn around on the runway and back-taxi to taxiway K knowing that the braking conditions were good on the runway. We informed mirabel radio; and other aircraft; of our intentions to back-taxi. We heard a response from an aircraft that was in the deicing car wash indicating that they would remain clear of taxiway K and out of our way. We taxied clear of the runway at taxiway K and began to taxi north toward taxiway I (which is designated as the westbound taxi route for that portion of the airport). The captain performed a braking check as we entered taxiway K. Braking was good on taxiway K. We also reported when we were clear of runway 6 and returning onto taxiway K -- transmitting this information on mirabel radio so all aircraft on the ground would be aware of our movements. We taxied at a very slow and deliberate pace. There was no evidence or information to indicate that taxiway I would be extremely icy. We observed that a cargo aircraft was in the deicing car wash and it was evident that he must have taxied from the cargo ramp area to deicing (which was to be our planned taxi route in reverse). As we slowly began the left turn from taxiway K onto taxiway I; the aircraft immediately began to slide to the right. The captain announced that the aircraft would not respond to tiller or brake inputs and that we were going to slide off the taxiway. The aircraft did slide at a 45 degree angle until it impacted the snow bank at the edge of the taxiway. The impact felt like normal gentle braking to a stop. The #2 engine was shut down immediately. The #1 engine was subsequently shut down. We then contacted mirabel radio and informed them of our situation and that we would need to get assistance from our ramp. At that point (for the first time); mirabel radio stated that we might have been better off using taxiway J (which apparently had been sanded). This was the first advisory regarding the taxiway conditions enroute to the cargo ramp area that we had received. We were not using taxiway J because it is designated as 1-way traffic in the easterly direction.

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Original NASA ASRS Text

Title: Widebody Captain reports taxiway excursion in freezing conditions during taxi to the ramp after landing at CYMX. The crew is advised after the fact that Taxiway J would have been a better choice due to it being recently sanded. CYMX is uncontrolled.

Narrative: While in our enroute descent to CYMX; we received ATIS information via ACARS. It indicated conditions as follows: -FZRA broken with temperature/dewpoint of M01/M04. Runway surface condition reported as 160 FT of the 200 FT wide runway was 60% bare and wet and 40% ice. Mirabel Radio provided normal Tower and Ground ATC communications (the field as non-tower operations). Mirabel Radio advised us on final approach that after landing only B05 was available for exit (we were landing on Runway 6) or we could reverse taxi on the runway to Taxiway K at the approach end of Runway 6. We were told the B-4 and B-6 exits were unusable. Landing and rollout were uneventful. Braking action was good. The aircraft was slowed to taxi speed by the B-5 exit point. We elected to turn around on the runway and back-taxi to Taxiway K knowing that the braking conditions were good on the runway. We informed Mirabel Radio; and other aircraft; of our intentions to back-taxi. We heard a response from an aircraft that was in the deicing car wash indicating that they would remain clear of Taxiway K and out of our way. We taxied clear of the runway at Taxiway K and began to taxi north toward Taxiway I (which is designated as the westbound taxi route for that portion of the airport). The Captain performed a braking check as we entered Taxiway K. Braking was good on Taxiway K. We also reported when we were clear of Runway 6 and returning onto Taxiway K -- transmitting this information on Mirabel Radio so all aircraft on the ground would be aware of our movements. We taxied at a very slow and deliberate pace. There was no evidence or information to indicate that Taxiway I would be extremely icy. We observed that a cargo aircraft was in the deicing car wash and it was evident that he must have taxied from the cargo ramp area to deicing (which was to be our planned taxi route in reverse). As we slowly began the left turn from Taxiway K onto Taxiway I; the aircraft immediately began to slide to the right. The Captain announced that the aircraft would not respond to tiller or brake inputs and that we were going to slide off the taxiway. The aircraft did slide at a 45 degree angle until it impacted the snow bank at the edge of the taxiway. The impact felt like normal gentle braking to a stop. The #2 engine was shut down immediately. The #1 engine was subsequently shut down. We then contacted Mirabel Radio and informed them of our situation and that we would need to get assistance from our ramp. At that point (for the first time); Mirabel Radio stated that we might have been better off using Taxiway J (which apparently had been sanded). This was the first advisory regarding the taxiway conditions enroute to the cargo ramp area that we had received. We were not using Taxiway J because it is designated as 1-way traffic in the easterly direction.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.