Narrative:

I was flying this entire flight from srr at 11;000 ft. I filed IFR because ceilings at destination were forecast to be low. I had heard several reports of light rime ice at 3;000 to 4;000 ft in the sjt area. Upon descent for approach tops were at 7;000 ft. Vectors were given to runway 3 ILS approach. I began picking up light rime at around 4;500 ft. I turned on pitot heat and carb heat. I also turned on defrosters for wind screen.eventually the windscreen frosted over almost 100%. There were two small holes where defrosters were melting the ice. On my side the defroster partially closed due to vibration and I did not notice until about a 1 mile final. I then opened it back up. Before the FAF (woole); I fixated on altitude because it was low and lost my scan. When I got back to the attitude indicator; I was in a steep right bank and headed almost 90 degrees to the right of approach course. I corrected the bank and headed back to intercept the approach course. At this point tower asked if I wanted to go missed. I declined because of the continuing buildup of ice. I did not want to go back up and pick up more ice. I was still not at the FAF and knew that I could salvage the approach. When getting back to the FAF the tower indicated that he had a low altitude warning. At this point my altimeter read about 3;400 ft. I should have been at 4;000 ft at the FAF. I continued the approach and attempted to climb; but with the business of the situation; I ended up staying at 3;500 ft until I intercepted the glideslope. Not too long after this; my wife told me she could see the ground; and then it went away again. I think we broke out less than 900 ft. My wife spotted the runway out of her small hole that the defroster made. I looked out the hole and saw that I was right of the runway. I corrected this looking out her side of the windscreen. At this point as we got closer to the ground; the ice started melting off of my side and a large chunk fell off. I was able to see the runway clearly when I was about 200 ft AGL. I was still carrying 80 to 90 KTS. The grumman slows down quickly so this was not a problem. Normal approach is 70 KTS. I used flaps; but the airplane was really squirrely so I dumped them completely (I then remembered my training to not use flaps if iced up). I had to go to near full power to maintain glideslope and 80 KTS until over the numbers. At this point; I was in the correct glideslope and the landing itself was non-eventful. After landing the leading edges of the wings and horizontal stab had up to 1/2' of ice on them. The spinner was coated with ice. The vertical stab had 1/4' of very clear solid ice that wrapped back several inches on both sides. Our planned route was sjt for fuel; then back home. The weather was not to improve until the next morning so we stayed in san angelo. There are several things here that I learned. One is that light rime is anything but light in this instance. The next time I hear of light rime; I will go someplace else. I also lost track of my options from the very beginning. I could have found better weather than what we encountered in san angelo. I still do not know why this didn't occur to me when I had nothing to do but kill time at 11;000 ft. I do wonder if two hours at 11;000 ft affected my judgment. In the past I have not hesitated to change flight plans or destinations for weather related reasons. This lesson will not go unheeded the next time I have a similar situation.

Google
 

Original NASA ASRS Text

Title: AA5A pilot reported picking up ice on approach to SJT that resulted in CFTT; momentary loss of control; and difficulty maintaining airspeed.

Narrative: I was flying this entire flight from SRR at 11;000 FT. I filed IFR because ceilings at destination were forecast to be low. I had heard several reports of light rime ice at 3;000 to 4;000 FT in the SJT area. Upon descent for approach tops were at 7;000 FT. Vectors were given to Runway 3 ILS approach. I began picking up light rime at around 4;500 FT. I turned on pitot heat and carb heat. I also turned on defrosters for wind screen.Eventually the windscreen frosted over almost 100%. There were two small holes where defrosters were melting the ice. On my side the defroster partially closed due to vibration and I did not notice until about a 1 mile final. I then opened it back up. Before the FAF (WOOLE); I fixated on altitude because it was low and lost my scan. When I got back to the attitude indicator; I was in a steep right bank and headed almost 90 degrees to the right of approach course. I corrected the bank and headed back to intercept the approach course. At this point Tower asked if I wanted to go missed. I declined because of the continuing buildup of ice. I did not want to go back up and pick up more ice. I was still not at the FAF and knew that I could salvage the approach. When getting back to the FAF the Tower indicated that he had a low altitude warning. At this point my altimeter read about 3;400 FT. I should have been at 4;000 FT at the FAF. I continued the approach and attempted to climb; but with the business of the situation; I ended up staying at 3;500 FT until I intercepted the glideslope. Not too long after this; my wife told me she could see the ground; and then it went away again. I think we broke out less than 900 FT. My wife spotted the runway out of her small hole that the defroster made. I looked out the hole and saw that I was right of the runway. I corrected this looking out her side of the windscreen. At this point as we got closer to the ground; the ice started melting off of my side and a large chunk fell off. I was able to see the runway clearly when I was about 200 FT AGL. I was still carrying 80 to 90 KTS. The Grumman slows down quickly so this was not a problem. Normal approach is 70 KTS. I used flaps; but the airplane was really squirrely so I dumped them completely (I then remembered my training to not use flaps if iced up). I had to go to near full power to maintain glideslope and 80 KTS until over the numbers. At this point; I was in the correct glideslope and the landing itself was non-eventful. After landing the leading edges of the wings and horizontal stab had up to 1/2' of ice on them. The spinner was coated with ice. The vertical stab had 1/4' of very clear solid ice that wrapped back several inches on both sides. Our planned route was SJT for fuel; then back home. The weather was not to improve until the next morning so we stayed in San Angelo. There are several things here that I learned. One is that light rime is anything but light in this instance. The next time I hear of light rime; I will go someplace else. I also lost track of my options from the very beginning. I could have found better weather than what we encountered in San Angelo. I still do not know why this didn't occur to me when I had nothing to do but kill time at 11;000 FT. I do wonder if two hours at 11;000 FT affected my judgment. In the past I have not hesitated to change flight plans or destinations for weather related reasons. This lesson will not go unheeded the next time I have a similar situation.

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.