Which of the following is a requirement for open time and trip trades?

The requirement for open time and trip trades involves ensuring that cumulative limits must not be surpassed. This means that when pilots are engaging in these trades, they need to comply with the established limits regarding their flying hours and duty periods. Adhering to these limits is crucial for maintaining safety standards and ensuring that pilots do not exceed their mandated work hours, which could lead to fatigue and impact their performance.

In the context of open time and trip trades, this requirement reflects regulatory standards set by aviation authorities, as well as the policies of the airline. Maintaining these cumulative limits is essential for both compliance with federal regulations and for the operational integrity of the airline.

The other options reflect concepts that might not align with the specific regulations around trading. For instance, trading of RAPs (Reserve Available Periods) for trips, requiring all pilots to be ready to work at any time, and disregarding seniority in bidding could lead to complications in scheduling and might not be permissible under the existing trade and bidding structures.