Where can you find the required oxygen levels?

The required oxygen levels can be found in the Operational Data Handling (ODH) document. This document typically includes critical performance data for the aircraft, including specifications for systems such as oxygen levels necessary for safe operation. It serves as a vital resource during flight operations to ensure that all systems are functioning within the required limits.

While other resources like the Quick Reference Handbook (QRH) and operational checklists do contain important information regarding procedures and operations, they might not provide the specific detailed data regarding oxygen levels that are usually found in documents focused on operational performance and maintenance standards like the ODH. Additionally, the maintenance manual is primarily aimed at providing guidance for maintenance and repair, rather than operational parameters needed in-flight. This distinction helps pinpoint why the ODH is the most suitable source for the required oxygen levels.