A B777 First Officer noted discrepancies between the electronic checklist (ECL) and two aircraft flight manual charts regarding rejected takeoff brake cooling times.

Narrative

While reviewing the electronic checklist (ECL) in flight; a discrepancy was noted between the ECL and the B777 flight manual (FM) concerning brake temperatures; specifically; the non-normal menu checklists for the Rejected Takeoff checklist. On page 6 of the Rejected Takeoff ECL; there is a table with brake temperatures and corresponding cooling times. These cooling times do not agree with the same table located in the flight manual Rejected Takeoff checklist. In the ECL; times are graduated in 10 minute intervals from 10-70 minutes for temperatures between 2.5 and 5.0 [degrees]. The corresponding times in the FM are all 10 minutes; regardless of temperature; an obvious error. I neglected to check the Annunciated Brake Temperature checklist in the ECL at the time; however I noted later that the corresponding FM checklist utilizes what seems to be the same erroneous brake temp/cooling time table as the FM Rejected Takeoff checklist. Both of these FM and ECL checklists refer the user to the performance chapter if the BTMS is inoperative. However; the brake cooling time table contains yet another table with both temperature values and cooling times that are different from both the ECL and the two FM non-normal checklists.