787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Flight Management, Navigation -
Flight Management System
Operation
Copyright © The Boeing Company. See title page for details.
D615Z003-TBC 11.31.11
Navigation system positions display on the left side of lines 2 through 4. The
bearing/distance is from the FMC position to the individual navigation system
position.
The FMC position displays on the ND at the tip of the triangle. All other positions
display relative to the FMC. The RADIO position is shown above as a •, but is not
shown on the ND. The ACTUAL navigation performance circles shown above do
not display on the ND.
Actual Navigation Performance
Actual navigation performance (ANP) is the FMC current computed position
accuracy. It is titled ACTUAL and displays on the POS REF page 2 for the
navigation system displayed in title line 1. ACTUAL navigation performance is a
circular prediction centered at the FMC position. Airplane position is estimated to
be within this ACTUAL navigation performance circle 95 percent of the time.
After a manual position update, the ACTUAL navigation performance of the
FMC changes to the ACTUAL navigation performance of the selected navigation
system. In the example above, a manual position update to the IRU L system
would change the FMC ACTUAL navigation performance to 5.7 NM. The FMC
then updates from the best available navigation system and eventually, the manual
update has no effect on position calculation. Some automatic updates can be
inhibited; GPS, VOR/DME and DME/DME updates on POS REF page 3 and
VOR/DME updates on the REF NAV DATA page. Inertial updates can not be
inhibited.
Required Navigation Performance
Required Navigation Performance (RNP) is the navigation accuracy required for
operation within a defined airspace. It is expressed in nautical miles. RNP values
have been published for areas of operation around the world. Operations in these
areas require on–board navigation systems to alert the flight crew if ANP exceeds
RNP. The FMC supplies a default RNP value for takeoff, en route,
oceanic/remote, terminal, and approach phases of flight. The flight crew may enter
an RNP value, if required. RNP displays on POS REF page 2.
Vertical Required Navigation Performance
Vertical RNP is the vertical navigation accuracy required for operation within a
defined airspace. It is expressed in feet. The FMC supplies a default vertical RNP
value for enroute, oceanic/remote, terminal, and approach phases of flight.The
FMC alerts the flight crew if vertical ANP exceeds vertical RNP. When required,
vertical RNP values may be manually entered or displayed on RNP PROGRESS
page 4/4. Manual entry of a vertical RNP value greater than that required for a
phase of flight results in the CDU help window message VERIFY VERT RNP –
PROG 4/X to display.
October 31, 2007
To Next Page
Loading...
