Narrative:

I was pilot monitoring on flight. I was not able to reach operations with our in range call. I called three times with no answer. When we were cleared the ILS 28; we were given the CTAF frequency from center. I switched to the frequency that I heard center give me: 124.12. I did not think to double check this against my approach plate. I made two radio calls. The first call was when I first switched frequencies; and the second was on a 4 mile final. Then I tried cuing the runway lights. I pressed the ptt button several times and the lights illuminated; further confirming that all was as it should be. We had the field in sight not long after passing the marker inbound. We made a point to inspect the runway conditions before deciding to land. The runway was clear of traffic and only a little blowing snow. I did notice a snow plow on the left side of the runway on a taxiway. We decided it was safe to land. After exiting the runway; the only place I noticed snow plows was on the ramp where we park. After deplaning the passengers an airport operations employee approached us concerned that we landed on runway 28 without transmitting on CTAF. She informed us that there were snow plows on the active runway until we were on final approach. She stated that she knew we were in the area; but was waiting to have the plows exit the runway until we transmitted on CTAF. We confirmed with her that CTAF was 124.12. She said no; it was 124.2. Did a radio check on 124.2; and an operations' vehicle responded saying our radio was working as it should. Obviously this is a very dangerous situation and one I have thought about much since. There were many contributing factors to this incident. First; this was the last flight of a 13 hour duty day. At the departure airport; we were busy with weight restrictions and trying to figure out an ATC reroute for this flight. As a result we arrived about an hour later than scheduled. Second; the poor weather was also a huge factor. Although the visibility was actually closer to 3 miles when we landed; it was forecast to be 1/2 SM with moderate snowfall and gusty winds. I was fairly fixated on making sure we had the required weather to do the approach legally and safely. Third; this was the first time both the captain and the first officer had landed at this airport. Fourth; the tower was closed for the night. We were told by center that the runway had been plowed and mu reading taken around less than an hour ago. So I had an expectation that the airport; being uncontrolled at the time of our arrival; would also be deserted except for us. The fact that operations did not answer contributed to this feeling; in my mind. Last; I should have double checked my CTAF frequency. I should have never relied on center; as lots of times frequency changes are misunderstood. I should have never assumed to runway to be clear of vehicles; even at an uncontrolled field. Personally; this is a situation that will not happen to my crew again. I will absolutely double check the CTAF frequency whether I am the flying pilot or not. I do hope that in the future the plows could monitor center as well as CTAF to ensure that no aircraft is on approach. I am thankful the airport operations employee was watching for us coming in and was able to warn the plows in enough time so that they could exit the runway. Luckily; the visibility was good and we would have had time to properly react and execute a go around procedure even if the airport employee had not reacted in time to ensure the runway was clear of vehicles. However; I do hope there can be a procedure change to prevent such a situation from ever occurring again.I feel the snow plows at uncontrolled airports should monitor the controlling center frequency during IMC conditions as well as CTAF. Personally; I will double check the correct CTAF frequency when handed off from center.

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Original NASA ASRS Text

Title: An EMB-135 crew which landed at a CTAF airport after Tower closure was unable to get a CTAF radio response because they had the incorrect frequency but were told by Airport Operations that snow plows were on the runway until just before they landed.

Narrative: I was pilot monitoring on flight. I was not able to reach Operations with our in range call. I called three times with no answer. When we were cleared the ILS 28; we were given the CTAF frequency from Center. I switched to the frequency that I heard Center give me: 124.12. I did not think to double check this against my approach plate. I made two radio calls. The first call was when I first switched frequencies; and the second was on a 4 mile final. Then I tried cuing the runway lights. I pressed the PTT button several times and the lights illuminated; further confirming that all was as it should be. We had the field in sight not long after passing the marker inbound. We made a point to inspect the runway conditions before deciding to land. The runway was clear of traffic and only a little blowing snow. I did notice a snow plow on the left side of the runway on a taxiway. We decided it was safe to land. After exiting the runway; the only place I noticed snow plows was on the ramp where we park. After deplaning the passengers an airport Operations employee approached us concerned that we landed on Runway 28 without transmitting on CTAF. She informed us that there were snow plows on the active runway until we were on final approach. She stated that she knew we were in the area; but was waiting to have the plows exit the runway until we transmitted on CTAF. We confirmed with her that CTAF was 124.12. She said No; it was 124.2. Did a radio check on 124.2; and an Operations' vehicle responded saying our radio was working as it should. Obviously this is a very dangerous situation and one I have thought about much since. There were many contributing factors to this incident. First; this was the last flight of a 13 hour duty day. At the departure airport; we were busy with weight restrictions and trying to figure out an ATC reroute for this flight. As a result we arrived about an hour later than scheduled. Second; the poor weather was also a huge factor. Although the visibility was actually closer to 3 miles when we landed; it was forecast to be 1/2 SM with moderate snowfall and gusty winds. I was fairly fixated on making sure we had the required weather to do the approach legally and safely. Third; this was the first time both the Captain and the First Officer had landed at this airport. Fourth; the Tower was closed for the night. We were told by Center that the runway had been plowed and Mu reading taken around less than an hour ago. So I had an expectation that the airport; being uncontrolled at the time of our arrival; would also be deserted except for us. The fact that Operations did not answer contributed to this feeling; in my mind. Last; I should have double checked my CTAF frequency. I should have never relied on Center; as lots of times frequency changes are misunderstood. I should have never assumed to runway to be clear of vehicles; even at an uncontrolled field. Personally; this is a situation that will not happen to my crew again. I will absolutely double check the CTAF frequency whether I am the flying pilot or not. I do hope that in the future the plows could monitor Center as well as CTAF to ensure that no aircraft is on approach. I am thankful the airport Operations employee was watching for us coming in and was able to warn the plows in enough time so that they could exit the runway. Luckily; the visibility was good and we would have had time to properly react and execute a go around procedure even if the airport employee had not reacted in time to ensure the runway was clear of vehicles. However; I do hope there can be a procedure change to prevent such a situation from ever occurring again.I feel the snow plows at uncontrolled airports should monitor the controlling center frequency during IMC conditions as well as CTAF. Personally; I will double check the correct CTAF frequency when handed off from Center.

Data retrieved from NASA's ASRS site as of July 2013 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.