Narrative:

Going into den last night we experienced severe icing; which lead to a buffet on short final from the tail trying to stall. I would like to tell you what happened and how I handled it and get your department's opinions as to what I did correctly and what I could have done better. The weather was changing rapidly going into den; when we departed for den it was 60 degrees and when we arrived it was 24. There were no reports of icing forecasted or reported by ATC. On the arrival ATC descended us to 8;000 while on downwind. This put us into a cloud layer that was producing mod icing; however ATC did not know this yet as this cloud layer had just formed. While in the cloud layer I mentioned to the first officer that earlier in the morning den had freezing fog and that I hope this would not develop into that condition. A few minutes later we noticed that we were picking up ice; so we added the wing anti-ice. While turning base; a flight that was in front of us reported mod icing at 8;000; ATC warned everyone. As we turned final the ice accretion was getting thick with at least 1/2 of an inch showing on the ice indicator; I had the first officer add another 5 knots to our final speed. (I had already added 5 for the wind). We were both getting anxious to get on the glideslope and start down; 8;000 was a bad place to be. As the glideslope started to come in; I added the gear followed by flaps three then full. I also hand fly all my approaches so the autopilot was off. As the aircraft slowed to ref plus 20 the aircraft started to shudder. I did nothing at first; and then it shuddered again! I recognized this shudder from my simulator training that I had just 3 weeks ago. I stated aloud that the tail is trying to stall and that is a buffet; I selected speed and increased the speed; and I pitched the nose up which stopped the buffet; I considered bringing the flaps back to three but decided that since we were only 800 AGL now I did not want to make any more configuration changes; I continued the approach in selected speed with a shallow noise attitude and came in fast and high but knowing I had a 12;000 foot runway I was not concerned about that. We reported severe icing at 8;000 for ATC. 1. I would like to know if my thought process and actions were correct. I believe it was the tail stalling as that is not protected from ice. In my previous life I taught tail stalling due to ice; so I believe the correct action is noise up (not down) bring flaps back up a notch; the lower the nose the higher the angle of attack on the tail. This is why I swallowed out the nose and increased speed. 2. I feel that since I hand fly all my approaches; this helped in identifying the buffet. 3. At this time I am still struggling with the decision not to go back to flap 3; do you have a thought? 4. Not to blow my own horn; but my first officer pointed out that most of our crews would not have recognized the buffet as a tail event; and would not have done what I did. Do you agree with that and is this now something we should add to our training? The only way I knew what to do was from past experience with this type of event. (Assuming you feel I handled it correctly) over all I wanted to let you know about the event since airbus and the FAA claim that the tail does not need to be protected; this is obviously untrue. I also am looking for guidance; you won't hurt my feelings; did I handle this correctly? What else could I should have done and most of all is this something we should share with all our crews?

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Original NASA ASRS Text

Title: A320 Captain experiences airframe buffet during approach in severe icing conditions. Believing tail icing is the cause airspeed is increased and a normal landing ensues.

Narrative: Going into DEN last night we experienced severe icing; which lead to a buffet on short final from the tail trying to stall. I would like to tell you what happened and how I handled it and get your department's opinions as to what I did correctly and what I could have done better. The weather was changing rapidly going into DEN; when we departed for DEN it was 60 degrees and when we arrived it was 24. There were no reports of icing forecasted or reported by ATC. On the arrival ATC descended us to 8;000 while on downwind. This put us into a cloud layer that was producing MOD icing; however ATC did not know this yet as this cloud layer had just formed. While in the cloud layer I mentioned to the First Officer that earlier in the morning DEN had freezing fog and that I hope this would not develop into that condition. A few minutes later we noticed that we were picking up ice; so we added the wing anti-ice. While turning base; a flight that was in front of us reported MOD icing at 8;000; ATC warned everyone. As we turned final the ice accretion was getting thick with at least 1/2 of an inch showing on the ice indicator; I had the First Officer add another 5 knots to our final speed. (I had already added 5 for the wind). We were both getting anxious to get on the glideslope and start down; 8;000 was a bad place to be. As the glideslope started to come in; I added the gear followed by flaps three then full. I also hand fly all my approaches so the autopilot was off. As the aircraft slowed to ref plus 20 the aircraft started to shudder. I did nothing at first; and then it shuddered again! I recognized this shudder from my simulator training that I had just 3 weeks ago. I stated aloud that the tail is trying to stall and that is a buffet; I selected speed and increased the speed; and I pitched the nose up which stopped the buffet; I considered bringing the flaps back to three but decided that since we were only 800 AGL now I did not want to make any more configuration changes; I continued the approach in selected speed with a shallow noise attitude and came in fast and high but knowing I had a 12;000 foot runway I was not concerned about that. We reported severe icing at 8;000 for ATC. 1. I would like to know if my thought process and actions were correct. I believe it was the tail stalling as that is not protected from ice. In my previous life I taught tail stalling due to ice; so I believe the correct action is noise up (not down) bring flaps back up a notch; the lower the nose the higher the angle of attack on the tail. This is why I swallowed out the nose and increased speed. 2. I feel that since I hand fly all my approaches; this helped in identifying the buffet. 3. At this time I am still struggling with the decision not to go back to flap 3; do you have a thought? 4. Not to blow my own horn; but my First Officer pointed out that most of our crews would not have recognized the buffet as a tail event; and would not have done what I did. Do you agree with that and is this now something we should add to our training? The only way I knew what to do was from past experience with this type of event. (Assuming you feel I handled it correctly) Over all I wanted to let you know about the event since Airbus and the FAA claim that the tail does not need to be protected; this is obviously untrue. I also am looking for guidance; you won't hurt my feelings; did I handle this correctly? What else could I should have done and most of all is this something we should share with all our crews?

Data retrieved from NASA's ASRS site 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.