Narrative:

First of all; this report is an afterthought about an incident about 2 months ago. I had initially intended to discuss this at a training event but reconsidered after consulting with an instructor.also; due to this late report; I cannot recall many details including the exact flight number & date. This should not have any impact on the event itself.we were dispatched to den & I do not recall the exact den weather forecast or all of the dispatcher remarks except that a bleeds off landing was planned. Flight was uneventful upon arrival in den area with ATIS indicating an overcast about 1;000 feet with good visibility. At about 12;000 feet MSL; I started the APU to prepare for the bleeds off landing. Just prior to descent into the overcast at about 10;000 feet; I noted an OAT of about -5C & turned on the engine a/I (anti-ice). Shortly after descending into the overcast we both noted a rapid accumulation of rime ice on the wipers and windshield. We both observed rime ice building on the wing leading edges. Wing a/I was turned on in accordance with [company] procedures. As we approached the FAF; I pulled out the QRH to begin the bleeds off landing checklist. The first item on the checklist was: wing a/I...off. After a quick discussion with my first officer (first officer) we decided that would not be safe considering the icing condition still present IMC. There was clearly a conflict in procedures that I had not foreseen.we began the ILS approach still IMC & still accumulating significant ice buildup on the windshield/wipers; but with wings now mostly clean. At about 900-1;000 feet AGL; we broke out of the overcast with good visibility & runway in sight. I quickly turned off both engine & wing a/I and completed the 'bleeds off landing checklist' prior to landing. While taxiing in with over an inch of ice on wipers; I began to wonder about the event. What if the overcast was @ 500 feet or lower? Does [the company] really want us to be playing with bleeds and switches on final approach IMC? Does [the company] want us playing with bleeds and switches on a missed approach at low altitude to ensure bleeds off performance? This problem cannot even be simulated since we use loss of visibility & less than 10C to 'pretend' icing conditions exist. The visual clues we use on the line to initiate wing a/I use are absent in the simulator.

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Original NASA ASRS Text

Title: B737 Captain reported a potentially hazardous situation exists due to a conflict between company anti-icing procedure and QRH bleeds off landing procedure.

Narrative: First of all; this report is an afterthought about an incident about 2 months ago. I had initially intended to discuss this at a training event but reconsidered after consulting with an instructor.Also; due to this late report; I cannot recall many details including the exact flight number & date. This should not have any impact on the event itself.We were dispatched to DEN & I do not recall the exact DEN weather forecast or all of the dispatcher remarks except that a bleeds off landing was planned. Flight was uneventful upon arrival in DEN area with ATIS indicating an overcast about 1;000 feet with good visibility. At about 12;000 feet MSL; I started the APU to prepare for the bleeds off landing. Just prior to descent into the overcast at about 10;000 feet; I noted an OAT of about -5C & turned on the Engine A/I (anti-ice). Shortly after descending into the overcast we both noted a rapid accumulation of rime ice on the wipers and windshield. We both observed rime ice building on the wing leading edges. Wing A/I was turned on in accordance with [company] procedures. As we approached the FAF; I pulled out the QRH to begin the bleeds off landing checklist. The first item on the checklist was: Wing A/I...off. After a quick discussion with my FO (First Officer) we decided that would not be safe considering the icing condition still present IMC. There was clearly a conflict in procedures that I had not foreseen.We began the ILS approach still IMC & still accumulating significant ice buildup on the windshield/wipers; but with wings now mostly clean. At about 900-1;000 feet AGL; we broke out of the overcast with good visibility & runway in sight. I quickly turned off both Engine & Wing A/I and completed the 'Bleeds off Landing Checklist' prior to landing. While taxiing in with over an inch of ice on wipers; I began to wonder about the event. What if the overcast was @ 500 feet or lower? Does [the company] really want us to be playing with bleeds and switches on final approach IMC? Does [the company] want us playing with bleeds and switches on a missed approach at low altitude to ensure bleeds off performance? This problem cannot even be simulated since we use loss of visibility & less than 10C to 'pretend' icing conditions exist. The visual clues we use on the line to initiate Wing A/I use are absent in the simulator.

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.