Narrative:

Both the captain and myself had not operated before in freezing fog; and neither of us recognized/remembered that condition was on the anti-icing sheet. The situation is not overly obvious in itself as there is no falling precipitation to cause awareness of the need for anti-icing. Received ATIS report during preflight preparations: WX was 600 RVR for most of the airport; with freezing fog reported (temperature -2 degrees C). This was the first time I had been in freezing fog conditions. My initial thoughts were that since visibility was less than 1 mi; and temperature was below 10 degrees C; that we would need to select engine anti-ice 'on' for takeoff. On the walkaround earlier; I saw no signs of ice/frost on the aircraft; so deicing was not necessary. Since precipitation was not actually falling (fog only); I was not thinking about deicing; as I would have been had precipitation been falling. The captain did not consider deicing either. We taxied out and took off of runway 30; without deicing. Once airborne; we were talking about another flight ahead of us that had delayed his departure upon reaching the runway; and let us depart first. I started wondering if there may have been something we missed; so I looked at the deice flow sheet; and noticed that freezing fog was a meteorological factor that required deicing. I pointed this out to the captain; who said he also was unaware that freezing fog was listed on the sheet. Curiosity concerning the other aircraft departure delay made the captain aware that deicing should have been performed in ZZZ. Possibly incorporate the scenario into simulator recurrent training; or an awareness memo.

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Original NASA ASRS Text

Title: A319 DEPARTS IN FREEZING FOG WITHOUT DEICING; AS REQUIRED BY FARS.

Narrative: BOTH THE CAPT AND MYSELF HAD NOT OPERATED BEFORE IN FREEZING FOG; AND NEITHER OF US RECOGNIZED/REMEMBERED THAT CONDITION WAS ON THE ANTI-ICING SHEET. THE SITUATION IS NOT OVERLY OBVIOUS IN ITSELF AS THERE IS NO FALLING PRECIP TO CAUSE AWARENESS OF THE NEED FOR ANTI-ICING. RECEIVED ATIS RPT DURING PREFLT PREPARATIONS: WX WAS 600 RVR FOR MOST OF THE ARPT; WITH FREEZING FOG RPTED (TEMP -2 DEGS C). THIS WAS THE FIRST TIME I HAD BEEN IN FREEZING FOG CONDITIONS. MY INITIAL THOUGHTS WERE THAT SINCE VISIBILITY WAS LESS THAN 1 MI; AND TEMP WAS BELOW 10 DEGS C; THAT WE WOULD NEED TO SELECT ENG ANTI-ICE 'ON' FOR TKOF. ON THE WALKAROUND EARLIER; I SAW NO SIGNS OF ICE/FROST ON THE ACFT; SO DEICING WAS NOT NECESSARY. SINCE PRECIP WAS NOT ACTUALLY FALLING (FOG ONLY); I WAS NOT THINKING ABOUT DEICING; AS I WOULD HAVE BEEN HAD PRECIP BEEN FALLING. THE CAPT DID NOT CONSIDER DEICING EITHER. WE TAXIED OUT AND TOOK OFF OF RWY 30; WITHOUT DEICING. ONCE AIRBORNE; WE WERE TALKING ABOUT ANOTHER FLT AHEAD OF US THAT HAD DELAYED HIS DEP UPON REACHING THE RWY; AND LET US DEPART FIRST. I STARTED WONDERING IF THERE MAY HAVE BEEN SOMETHING WE MISSED; SO I LOOKED AT THE DEICE FLOW SHEET; AND NOTICED THAT FREEZING FOG WAS A METEOROLOGICAL FACTOR THAT REQUIRED DEICING. I POINTED THIS OUT TO THE CAPT; WHO SAID HE ALSO WAS UNAWARE THAT FREEZING FOG WAS LISTED ON THE SHEET. CURIOSITY CONCERNING THE OTHER ACFT DEP DELAY MADE THE CAPT AWARE THAT DEICING SHOULD HAVE BEEN PERFORMED IN ZZZ. POSSIBLY INCORPORATE THE SCENARIO INTO SIMULATOR RECURRENT TRAINING; OR AN AWARENESS MEMO.

Data retrieved from NASA's ASRS site as of January 2009 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.