FLS Guidance Approach Mode

Thanks to Airbus for facilitating and enhancing the NON precession approach by facilitating the FLS To fly a NPA “ ILS alike .

What is the FLS ?how does it work ? When is it used?

FLS is referred To FMS landing system

it’s approach guidance mode is not an approach type . Airbus aircraft FLS used to fly all of the non-precession Straighten app like VOR ,VOR DME ,NDB,NDB DME , RNAV(GNSS ) ,LOC ,LOC back course and ILS with glide slope out . Not for RNP AR approach.

FLS uses the information from the navigation database to compute a virtual FLS beam then the FMS sends this FLS beam and aircraft position and aircraft Baro-Altitude from the Fm system to the (MMR) to compute and display the lateral and vertical angular deviation from FLS virtual beam like an ILS Approach.

FLS beam characterized :

1- An approach course on PFD like loc but it’s materialized by a double dagger 2- materialized by a double dagger slope 3- An Anchor point which is usually runway threshold ( ident is Rwy if it is located on the threshold (showing EP in other cases )

Earth Curvature : As the final path crossing Altitudes are geometric Altitudes referring to the Anchor point,a slight Altitude deviation between aircraft altimeter and intercepting Altitudes by 50 ft higher .

Temperature and QNH operations: FLS beam is corrected for temperature below ISA thanks to temperatures entered in the PERF APP page. The crew should pay attention to the altimeter setting and any altimeter setting change during the Approach as 1HPA altimeter setting error moves the F-G/S vertical profile about 30ft up or down.

When the crew insert on the MCDU performance page the correct OAT the FLS vertical beam (F-G/S) computation takes into account the effect of the OAT on obstacle clearance.

FLS CAPABILITY:

FLS Approach Capability’s displayed on the FMA when LS push bottom is selected on 10000ft to help the crew to determine the approach strategies,

if FLS mode is not available due to app construction the (no FLS for this App) pop out on the scratch pad . As a consequence for any system affecting the FLS capability, the ECAM STATUS displays the FLS

*F-APP: deviations and F-LOC and F-G/S are reliable. *F-APP+RAW: crew can refer to FLS and must cross check with navaid RAW data *RAW : the flight crew must not use the FLS

FLS guidance: 1-FLS beam is displayed in magenta dash line on the ND and it is 80 nm long and it could be intercepted at any point along the line . 2-The offset between final approach course and runway course does not exceed 50 degrees. 3- FLS guidance outside the published approach does not guarantee obstacles clearance. 4- when visual contact with runway AP/FD disconnects, select TRK FPA (bird) .

MCDU flight plan tolerance :

* 3 degrees difference between the MCDU and final track to a conventional radio navaid chart .

* 0.1 degree between The MCDU and final vertical path on app chart

* 1 degree between the MCDU and final lateral track on App chart .

By captain / Ahmed shebl A320/321/330/310/300-600 , FAA ATP,CFI,CFII &MEI ,MBA aviation management