Which memo indicates that an incorrect configuration is present before takeoff?

The T.O. Memo, or Takeoff Memo, is specifically designed to provide critical pre-takeoff information regarding the aircraft's configuration. This memo alerts the flight crew if there are any incorrect settings or configurations that could impact safety during the takeoff phase. For instance, if the flaps or slats are not set correctly, the T.O. Memo will display a warning to the pilots, ensuring that they address the issue before commencing takeoff. This proactive safety feature helps prevent potential mishaps, emphasizing the importance of correct aircraft configuration for safe flight operations.

In contrast, while other memos may serve different functions, they do not focus on indicating configuration issues related to takeoff. For example, the LDG Memo pertains to landing configuration alerts, the Not Applicable Memo indicates conditions that do not apply, and the System Check Memo is used for other system status checks. Hence, the T.O. Memo is the most appropriate indicator of pre-takeoff configuration correctness.