Narrative:

Denver was a wintry mess. It was -11 degrees and fine crystalline snow was both falling and blowing around. Braking action and visibility were both variable and poor. When we pushed back; we were told which departure runway to expect and we briefed the performance and routing for that runway and proceeded to the J pad deicing area. The deicing area is comprised of two deicing areas sandwiched by three taxiways and bordered by four unimproved areas. The taxiways are defined by painted lines and flush green line centerline lights which were mostly obscured by snow. As our deicing was wrapping up; we were told by ground that we would depart from a different runway. This is a classic 'out of the green' scenario requiring new performance calculations and route planning. Because of obscuration; there was no visible way to distinguish the boundaries of the ramp areas versus the designated taxiways other than clear ways between deice trucks and aircraft and tire tracks which were all over the place. Because the denver airport is so physically huge and complicated; its taxi chart details are tiny and vast. I had a reasonable idea of where I needed to go; but no way to verify that it was correct. Trying to figure out how to manage risks with resources; I came to the conclusion that I needed to turn on the own ship display feature on the efb. It was a godsend. It allowed me to verify where I needed to go rather than guess and; when we came upon a patch where we could briefly see the green centerline lights; they verified that we were exactly where we were supposed to be. I can't tell you how reassuring and helpful that was. I know that we are not supposed to use the own ship feature; but in this particular situation it would have been a violation of captain's [SOP; CRM;] and common sense responsibilities not to.

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Original NASA ASRS Text

Title: B737 Captain reported using his EFB for taxi orientation on a snowy day in DEN; even though it was against company procedure to do so.

Narrative: Denver was a wintry mess. It was -11 degrees and fine crystalline snow was both falling and blowing around. Braking action and visibility were both variable and poor. When we pushed back; we were told which departure runway to expect and we briefed the performance and routing for that runway and proceeded to the J Pad deicing area. The deicing area is comprised of two deicing areas sandwiched by three taxiways and bordered by four unimproved areas. The taxiways are defined by painted lines and flush green line centerline lights which were mostly obscured by snow. As our deicing was wrapping up; we were told by Ground that we would depart from a different runway. This is a classic 'out of the Green' scenario requiring new performance calculations and route planning. Because of obscuration; there was no visible way to distinguish the boundaries of the ramp areas versus the designated taxiways other than clear ways between deice trucks and aircraft and tire tracks which were all over the place. Because the Denver Airport is so physically huge and complicated; its taxi chart details are tiny and vast. I had a reasonable idea of where I needed to go; but no way to verify that it was correct. Trying to figure out how to manage risks with resources; I came to the conclusion that I needed to turn on the Own Ship display feature on the EFB. It was a godsend. It allowed me to verify where I needed to go rather than guess and; when we came upon a patch where we could briefly see the green centerline lights; they verified that we were exactly where we were supposed to be. I can't tell you how reassuring and helpful that was. I know that we are not supposed to use the Own Ship feature; but in this particular situation it would have been a violation of Captain's [SOP; CRM;] and common sense responsibilities not to.

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.