Perform a LNAV/VNAV approach (A320)[PDF]
- 1 INTRODUCTION
- 2 FLIGHTPATH MANAGEMENT
- 3 PREPARATORY WORK
- 4 AIRCRAFT GUIDANCE MANAGEMENT
- 5 AIRCRAFT CONFIGURATION MANAGEMENT
- 6 See also
- 7 Reference
- 8 Author
This briefing shortly describes the basic procedures to perform RNAV (GNSS) approaches with LNAV/VNAV minima. The differences with LNAV only, are mainly based on the criteria of design:
- LNAV/VNAV requires a V/DEV indicator as the primary source for vertical navigation, provides a DH as low as 250ft depending on the obstacles around, and ensures the maximum vertical deviation along the Final Descent (75ft max).
- LNAV only ensures vertical obstacle clearance by crossing specific altitudes over specific fixes along the approach. It’s like a conventional NPA which provides a more exact lateral navigation due to the accuracy of the GPS receivers
In Airbus philosophy, there are two types of Autopilot/Flight Directors modes used during the approach, commonly referred to as “Guidance" (See table below in Aircraft Guidance Management section).
LATERAL FLIGHT PATH
RNAV GNSS approaches are procedures based on GNSS lateral navigation to follow a defined track. The lateral flightpath will be monitored by a cross track deviation value indicated on the Navigation Display (or L/DEV in some aircraft).
A lateral deviation of 0.1nm is accepted as a standard value during the approach.
VERTICAL FLIGHT PATH
In LNAV/VNAV, a deviation of ½ a dot in the V/DEV vertical scale is accepted as a standard value. 1 dot equals to a deviation of 100ft.
RNAV (GNSS) APPROACH 13R
Final Approach Course: 134o
FAF: BO612 at 12000ft
Glide path: 3.0o
Use the “TOP HAT” method as per AIRBUS SOP for descent preparation. Follow the flow from left to right.
- Pay particular attention to the F-PLN sequence. Select the appropriate RNV approach (RNAV GNSS). Make a vertical revision and check altitude and speed constraints for each point along the approach. Press key R2:
2. Check that the reported temperature at the airport is within the limits for the procedure.
3. On PROG page, insert the reference runway threshold in order to monitor the position during the approach.
AIRCRAFT GUIDANCE MANAGEMENT
You can also find it useful for LNAV mínima approaches using both FINAL APP and NAV/FPA modes. (Refer to Perform a LNAV approach (A320) for LNAV ONLY info)
As mentioned earlier during descent preparation, the FDP can be identified as the point on the MCDU F-PLN with the value of the Final Descent Angle (usually -3.0o). It can also be identified by looking at the blue “hockey arrowed stick” over the FDP. Sometimes the FDP and the charted FAF are the same, but there are some cases where the FDP might be located at a different point, before the FAF. (See the picture below)
COMMON PARAMETERS FOR STABILIZATION DURING THE APPROACH
- Speed: between VAPP -5kt // +10kt
- V/S: Max -1000ft/min in descent
- Bank: Max 7o
- Pitch: Max -2.5o // +10o
- Cross Track: Max XTK (lateral deviation) of 0.1NM
- V/DEV: Max ½ dot
AIRCRAFT CONFIGURATION MANAGEMENT
- At Green Dot speed, select Flaps 1
- Flaps 1 should be set more than 3nm from the FDP
- Check deceleration towards S speed
- For decelerated approach, reach the final descent path with F1 and S speed.
- Set Flaps 2
- This flap setting must be set by the latest at 2000 feet AGL.
- Check deceleration towards F speeed.
- When Flaps at 2, “Landing Gear Down”
- Set Landing Gear Down
- Check auto brakes
- Arm the spoilers
- Turn on “Taxi Light and RWY turn off” switches
- Flaps 3 and Flaps Full as required
- Landing checklist
- A320 FCOM/FCTM
- Getting to grips with PBN
- VID 109661 - Creation
DATE OF SUBMISSION
- 07:19, 23 February 2021
- This documentation is copyrighted as part of the intellectual property of the International Virtual Aviation Organisation.
- The content of this documentation is intended for aviation simulation only and must not be used for real aviation operations.