Narrative:

We were holding short of runway xx at taxiway xx. Tower cleared us for takeoff on runway xx shortened. In the past; I have back taxi from [taxiway] xx into position on runway xx for takeoff. When we accepted the clearance; we stated we were back taxiing and ATC did not respond. After I back taxied this time; tower says that it is notamed out that we cannot back taxi; but I had already done so.the NOTAM came out [the previous month] and I have not been in ZZZ since then. I did not interpret the NOTAM to mean I could not back taxi since I had done it before. Our takeoff numbers are based on 1;000 feet. Shortened from the threshold of runway xx not from taxiway xx which is nearly 1;400 feet. From the threshold. So; for me to accept a taxiway xx takeoff; I would have to have run new takeoff numbers. On my release; there is no data for taxiway xx takeoff. While the declared distant in one NOTAM is 5;650 feet.; we are not allowed to use all of that in the next NOTAM when we are unable to back taxi from taxiway xx.if ATC does not want us to back taxi; they need to state that this will be a takeoff from runway xx/taxiway xx. The company needs to provide us with takeoff data for runway xx/taxiway xx departures if this is what ZZZ airport is requiring us to do. Notams need to be revised so they are not conflicting. Do not state in one that I have 5;650 feet and in the next NOTAM that I am not allowed to use all of that declared length.

Related reports:

Google
 

Original NASA ASRS Text

Title: CRJ-200 flight crew reported conflicting NOTAMs referencing a runway with restrictions and ATC issuing an alert after the crew was in position ready for takeoff.

Narrative: We were holding short of Runway XX at Taxiway XX. Tower cleared us for takeoff on Runway XX shortened. In the past; I have back taxi from [Taxiway] XX into position on Runway XX for takeoff. When we accepted the clearance; we stated we were back taxiing and ATC did not respond. After I back taxied this time; Tower says that it is NOTAMed out that we cannot back taxi; but I had already done so.The NOTAM came out [the previous month] and I have not been in ZZZ since then. I did not interpret the NOTAM to mean I could not back taxi since I had done it before. Our takeoff numbers are based on 1;000 feet. shortened from the threshold of Runway XX not from Taxiway XX which is nearly 1;400 feet. from the threshold. So; for me to accept a Taxiway XX takeoff; I would have to have run new takeoff numbers. On my release; there is no data for Taxiway XX takeoff. While the declared distant in one NOTAM is 5;650 feet.; we are not allowed to use all of that in the next NOTAM when we are unable to back taxi from Taxiway XX.If ATC does not want us to back taxi; they need to state that this will be a takeoff from Runway XX/Taxiway XX. The company needs to provide us with takeoff data for Runway XX/Taxiway XX departures if this is what ZZZ airport is requiring us to do. NOTAMs need to be revised so they are not conflicting. Do not state in one that I have 5;650 feet and in the next NOTAM that I am not allowed to use all of that declared length.

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.