A pilot is flying an aircraft equipped with a Flight Management System (FMS) that integrates GPS and other navigation sensors. This system displays 'RNP 0.3' as the current navigation performance. What does this indicate?
- AThe aircraft's navigation system has a 0.3-degree accuracy for bearing information.
- BThe aircraft is currently operating at 0.3 times the required navigation performance for the airspace.
- CThe aircraft's navigation system can maintain position within 0.3 nautical miles for 95% of the flight time.
- DThe system is providing a warning that the navigation performance is degraded to 0.3 nautical miles.
Show answer & explanationAnswer & explanation
Correct answer: C. The aircraft's navigation system can maintain position within 0.3 nautical miles for 95% of the flight time.
Required Navigation Performance (RNP) is a statement of the navigation performance necessary for operation within a defined airspace. An RNP value, such as RNP 0.3, indicates that the aircraft's navigation system can maintain its position within 0.3 nautical miles of the desired track for at least 95% of the flight time.
Why the other options are wrong
- A. RNP refers to position accuracy in nautical miles, not bearing accuracy in degrees.
- B. RNP 0.3 is a performance level, not a ratio of performance to requirement; it is the required performance itself.
- D. An RNP value like 0.3 indicates the achieved performance level, not necessarily a degradation warning unless the required RNP for the airspace is higher.
Required Navigation Performance (RNP)
RNP is a statement of the navigation performance necessary for operation within a defined airspace, expressed as a distance (e.g., 0.3 NM) within which the aircraft's position must be for 95% of the flight time.
- Indicates navigation system accuracy.
- Expressed in nautical miles.
- 95% containment value.
- Includes onboard performance monitoring and alerting.
Memory trick: RNP: Required Navigation Performance is a 'Number' of miles, 95% of the 'Period'.