Yes you can be RNP-10. In the following cases:
6.2 hours after placing IRU in navigation mode (pure inertial), or
5.9 hours after the last automatic DME/DME position update, or
5.7 hours after the last automatic VOR/DME position update.
The FMS continuosly monitors input from the available naviagtion sensors (radios, IRUs, and GNS) to compute a position and actual navigation performance "ANP" value in units of nautical miles. The FMS RNP function is used as a integrrity monitor for airplane position.
If the plane is certificated to fly in RNP-10 airspace then, you can fly without GPS for a flight time not to exceed:
6.2 hrs.
5.9 hrs.
5.7 hrs.
Originally Posted by
felixthecat
NEWYEAR quoted this a while back
What aircraft is this for, and if not aircraft specific where do you find these details? Never seem them in the 777 FCOM or other documents.
I'm happy enough that on a 777 the loss of both FMC really isn't that big a deal since the CDUs have the current route and any arrival already programmed in their memory, plus ALT NAV lets you program via LAT/LONG. Positional info now just via ADIRU, and slowly degrades over time when out of nav beacon range.
Check your 777 MEL under FMC and you might find the same or similar numbers to what is posted above. Also, any plans ahead of time for flap maneuver speeds, go-around N1, etc. How about all those gaps that may be visible between some of the waypoints in the STAR? Any plans ahead of time if ATC gives a different STAR? There are a few things to plan for ahead of time.