Originally Posted by
8che
This message is not relevant (on the ground) if the officially reported ATIS indicates icing conditions. TAT is not part of ground assessment. Ice detection is not enabled on the ground. This checklist is not relevant until airborne...
Can you please for once show where your information comes from?
The Boeing statement is to use OAT, Boeing does not anywhere say TAT cannot be used on the ground. OAT gives you more freedom, there is nowhere any requirement stated that OAT is ONLY metar reported temperature. If you decide to switch if to AUTO, fine. If you decide to keep it ON, fine, but be aware you are overruling a checklist in theory you are required to follow. I don't know any company that is going to hassle you for this decision. But don't come claiming this story about captaincy, common sense, blablabla... because you are not doing anything wrong by following the checklist. The Boeing statements on checklist creation are common for all fleets, however you abuse those statements. Boeing is not saying anywhere to "disregard" a checklist, Boeing does not say this checklist is not "relevant" in this situation.
"Common sense" is the most abused phrase in aviation by pilots, as is "we've been doing it like that for years". My request remains: show me where Boeing states B777 TAT is unreliable on the ground.