What is the minimum requirement for long-range navigation systems when operating in oceanic and remote areas according to RNAV 10?

In oceanic and remote areas, RNAV 10 requires aircraft to be equipped with two independent and serviceable long-range navigation systems to ensure safety and reliability during navigation. The need for redundancy in navigation systems is pivotal when operating far from land, as it minimizes the risk of total navigation failure.

Having a combination of systems like an Inertial Navigation System (INS), an Inertial Reference System (IRS) / Flight Management System (FMS), or a Global Navigation Satellite System (GNSS) ensures that the aircraft can maintain accurate positioning even if one of the systems fails. This redundancy is crucial because it allows pilots to cross-check system performance and ensures continued navigational capability during long ferry flights over oceans or in remote regions.

This requirement reflects best practices in aviation safety, which stem from experiences and lessons learned in the industry. Additionally, the other options either specify incorrect combinations of navigation systems or do not meet the redundancy requirement outlined by RNAV 10, which emphasizes that at least two independent systems are essential for safe operations in these challenging environments.