The 900 deviation code is used for what type of delay?

• A. Aircrew
• B. Maintenance
• C. Changes
• D. Four

Answer: (B)

This item tests how delays are categorized by deviation codes. The 900 deviation code block is reserved for delays caused by maintenance actions on the aircraft or related equipment. When a sortie must be delayed because of a fault found, a repair is needed, parts are unavailable, or troubleshooting is required, the delay is recorded under a maintenance-related code. This makes it clear that the cause is maintenance and helps track and analyze maintenance impacts on schedules. Other kinds of delays—such as those due to aircrew readiness or changes to the mission plan—fit under different code groups, and a non-existent option like “Four” isn’t applicable. So the delay type described by the 900 deviation code is maintenance.