Flight management systems

Question 1

Function of FMS

Answer 1

navigation database: airports, navaids, waypoints, arrival routes, departure routes and instrument approaches
flight data storage: aircraft mass and balance data, aircraft specific performance database
input and storage of flight plan, storage of ‘company routes’
best estimate of aircraft position combining navigation sources and calculation of position accuracy
performance prediction and flight path optimisation
output of data to autopilot/AFDS, EFIS, MFDs and associated systems

Question 2

FMS tasks and benefits

Answer 2

accurate positioning by automatically tuning appropriate aircraft receivers to navigation beacons, Kalman filter to integrate navigation data
navigation and flight guidance
monitoring the aircraft flight envelope and performance and computing optimum speed
optimise the aircraft’s performance and minimise flight costs and pilots work load(cost index 0-200)

Question 3

RNAV concept

Answer 3

navigation not confined to ground beacons
RNAV capable FMS use a combination of VOR, DME, GPS &/or INS to determine position IFR airborne equipment provides RNAV capability using GPS positioning and must employ ABAS(RAIM) or SBAS to monitor and predict performance
more direct

Question 4

Requirements

Answer 4

B-RNAV(RNAV5)

P-RNAV(RNAV1)

Question 5

B-RNAV(RNAV5)

Answer 5

enroute airspace +/- 5nm for 95% of the flight time
mandatory in European airspace
airspace must be radar monitored

Question 6

P-RNAV(RNAV1)

Answer 6

terminal airspace +/- 1nm for 95% of the flight time
P-RNAV approaches must be radar monitored
not suited for difficult terrain

Question 7

LNAV

Answer 7

lateral navigation
navigation mode of an RNAV capable FMS
provides a precise lateral path defined by waypoints and legs

computes guidance commands for the autopilot or flight director to follow the desired path

Question 8

VNAV

Answer 8

calculates and provides the vnav flight profile which is the desired flight trajectory of the aircraft in the vertical plane
flight profile reflects all speed and altitude restrictions as loaded in the FMS
it computes guidance commands for the autopilot or flight director and auto throttle to follow the vertical profile

Question 9

RNP(required navigation performance)

Answer 9

RNP specification - requirement for an on-board navigation performance monitoring and alerting
RNP is a performance standard used by manufacturers, operators and regulatory authorities to indicate an aircraft’s navigation performance requirement

Question 10

ANP and RNP

Answer 10

ANP
circle centred on FMS position defining the accuracy of the navigation for 95% of the flight time

RNP
expressed as a distance in nm from an intended position
total navigation system error allowable

If ANP circle exceeds RNP, pilot is alerted

Question 11

Benefits of RNP and RNAV

Answer 11

reduced route separation resulting in more effective use of airspace
narrower terrain/obstacle path to consider
lower weather minimum for approach and landing
lower decision height to go visual and lower minimum required visibility
reduced crew and controller workload
more direct flight capability

Question 12

FANS

Answer 12

FANS 1/A
common standard for traffic in EUROCONTROL area and N.Atlantic
communication improvements - CPDLC
navigation improvements - GNSS, RNP, ANP