65 Universal UNS-1C FMS

Question 1

What is FMS

Answer 1

The FMS is a fully integrated navigation management system designed to provide the pilot with centralized control for the computer based flight planning and fuel management. The FMS is capable of navigating along pilot-programmed flight paths, which can include SID, airways, in-flight manoeuvres, holding patterns, STAR, approaches and runway data. If properly equipped Search Patterns may also be flight planned.

Question 2

UNS-1C Components

Answer 2

UNS-1C CDU x 2

Data transfer Unit x 1

Airdata converter unit (ACU) x 2

Glareshield advisories x 2

GPS antennas x 2

Config module

Question 3

NTS connectivity to FMS

Answer 3

NTS computer will accept only 1 GPS data line and 1 posn data line from cockpit
NTS selector switch is used to connect either FMS#1 or FMS#2 to NTS

Question 4

RNAV and RNP

Answer 4

RNAV: Area Navigation: method of navigation that permits aircraft operation on any desired course within the coverage of station-referenced navigation signals or within the limits of a self contained system capability, or a combination of both.
Navigation does not need to be beacon to beacon
Can program route into FMS
Conserves flight distance
Reduces congestion
Allows flights into airports without beacons
RNP (Required Navigation performance):
Like RNAV operations with on board navigation containment, monitoring and alerting
Expressed in nautical miles and percentage. A statement of the navigation performance accuracy necessary for operation within a defined airspace.

Increasing use of GPS based navigation vice traditional navaid to navaid navigation
Many RNAV (RNP) approaches in operation today and becoming more popular
RNAV Q and T routes increasingly preferred routing over conventional airways

Question 5

FMS Heading Source

Answer 5

Defaults to AHRS 1&2 during startup
After IRU aligned, box will automatically choose best available heading source normally the IRU
Can select AHRS 1 or 2 manually
If manual selection made, auto-select disabled for rest of flight
UNS-1C uses true headings from IRU which is converted into a magnetic course which is displayed on the EHSI
MAG VAR table runs out at 73 deg N (CT-142 is not certified to fly above 73N)
Can set MAG VAR manually

Question 6

FMS Jeppensen Data

Answer 6

Standard data includes VORs, NDBs, enroute intersections airports, etc.
Extended data adds SIDs, STARs, approach and runway info for selected airports
Extended Database for all hard surface runways over 4000 feet.

Question 7

FMS Pilot Data Base

Answer 7

Personally tailored data such as routes, waypoints, SIDs, STARs, approaches, etc
Create a pilot data disk with Off-line Flight Planning software and load via DTU (or)
Create pilot data in a CDU and save to disk – erased at eatch power off cycle, must reload via DTU
Retained up to 4 hours IF the STBY power off mode is used

Question 8

GPS – RAIM - HIL

Answer 8

Receiver Autonomous Integrity monitoring
4 sats provides 3D position
5 sats provides RAIM (bad sat present)
6 sats provides FDE (ident & drop bad sat)
HIL – what is size of error that FDE can exclude (depends on #sats & sat geometry)
HIL exceeded → GPS INTEG warning given

Question 9

GPS Integ Alarm

Answer 9

Enroute: HIL > 2.0nm after 27 secs
Terminal: HIL > 1.o nm after 7 secs
Approach: HIL > 0.3 nm after 7 secs
Bottom line – can’t start or continue GPS only approach with GPS INTEG warning on
GPS Integ off → HIL is OK → RAIM is available
RAIM check = HIL check

Question 10

What inputs are available to the FMS to determine its best computed position?

Answer 10

GPS 1, GPS 2, IRU

Question 11

Define Best computed position?

Answer 11

Blend of the two GPS positions and the IRU position using a statistical model