When not in radar contact, what should be used to clear traffic during climbs and descents greater than 1000ft?

The appropriate method for clearing traffic during climbs and descents greater than 1000 ft when not in radar contact is using an integrated outside scan and TCAS (Traffic Collision Avoidance System). TCAS enhances the pilot’s situational awareness by providing traffic advisories and alerts regarding nearby aircraft, including their relative altitude and the likelihood of a collision. This technology is crucial in maintaining safety when the aircraft is not under radar surveillance.

In conjunction with TCAS, the integrated outside scan involves a visual check of the surrounding airspace to identify potential conflicts. Combining the insights gained from TCAS with a thorough visual scan effectively allows pilots to ascertain traffic in the vicinity, which is essential during significant altitude changes. Engaging with both systems creates a more comprehensive understanding of the aerial environment.

Other methods listed, such as using radar contact or ATC instructions, are inherently limited without radar surveillance, meaning they wouldn't be applicable in this scenario. For chart reference and outside visual scans, while important, this combination does not provide the continuous monitoring and proactive alerts that TCAS offers, making it less effective for the specific requirement stated.