To satisfy the CMNPS navigation systems requirement, aircraft operating on high-level airways or company-approved routes must be at least equipped with:

To satisfy the CMNPS navigation systems requirement, aircraft operating on high-level airways or company-approved routes must be at least equipped with:

• A. a single long range RNAV system, plus a short range navigation system
• B. dual short range navigation systems
• C. two long range RNAV systems or one navigation system using the inputs from one or more sensor systems, plus one short range navigation system
• D. three long range RNAV systems

Answer: (B)

The main idea is having redundancy in navigation sources to keep you on course even if one system fails. For high-level airways or company routes, you want reliable position awareness without being tied to a single method. Short-range navigation systems rely on ground-based navaids like VOR/DME and localizers, which don’t depend on satellites. Having two independent short-range navigation receivers gives you a robust non-satellite backup: if one receiver or its signal is degraded or inoperative, the other can still provide accurate navigation to maintain the route. This makes the flight’s navigation capability resilient in a variety of situations, including GNSS outages or signal interference. The other options emphasize long-range RNAV or mixed systems, which may rely more heavily on satellite signals and may not provide the same assured fallback solely with non-satellite navaids.

The main idea is having redundancy in navigation sources to keep you on course even if one system fails. For high-level airways or company routes, you want reliable position awareness without being tied to a single method. Short-range navigation systems rely on ground-based navaids like VOR/DME and localizers, which don’t depend on satellites. Having two independent short-range navigation receivers gives you a robust non-satellite backup: if one receiver or its signal is degraded or inoperative, the other can still provide accurate navigation to maintain the route. This makes the flight’s navigation capability resilient in a variety of situations, including GNSS outages or signal interference. The other options emphasize long-range RNAV or mixed systems, which may rely more heavily on satellite signals and may not provide the same assured fallback solely with non-satellite navaids.