1. RNAV Procedures
AIXM Procedures Seminar 1-2 Sept 2010

2. Conventional Procedure Description
Conventional Instrument Flight Procedures
Published in AIP
Defined as textual descriptions supported by charts
The charts are used by the pilots and ATC
Recommend that AIP does not provide RNAV interpretations of procedures not designed according to RNAV procedure design methodology
Data Houses and OEM best placed to interpret requirement for individual FMS/RNAV. However, description must be clear and unambiguous
AIXM Procedures Seminar 1-2 Sept 2010

3. RNAV Procedure Description
RNAV Instrument Flight Procedures
Published in AIP
Defined by unambiguous descriptions supported by charts
Provides Data Hobase providers require clear and unambiguous procedure descriptions and use the charts to validate/check
AIXM Procedures Seminar 1-2 Sept 2010

4. Coding the Procedure
Procedure coding
Translates textual description of route or a terminal procedure into a format useable in RNAV systems.
Two steps:
Translation from AIP text/chart into ARINC 424 alphanumeric code
Translation from ARINC 424 into avionic specific binary code (known as ‘packing’)
Successful translation into ARINC 424 depends upon a clear and unambiguous description of the route/procedure.
AIXM Procedures Seminar 1-2 Sept 2010

5. ARINC 424
Industry standard for the transmission of data
Navigation element uniquely defined and stored
Can be accessed for any intended navigation purpose
Developed to allow RNAV to be used on conventional procedures
ICAO PANS-OPS references ARINC 424 rules and methodologies
Note: ARINC 424 not developed for design of flight procedures,
BUT: understanding of ARINC 424 enables procedure designers to perform their tasks so that misinterpretations and errors are significantly reduced
AIXM Procedures Seminar 1-2 Sept 2010

6. En-Route Coding
Individual airway legs defined by waypoint and altitude constraints
En-route holds not associated with any aerodrome and identified as ‘ENRT’
AIXM Procedures Seminar 1-2 Sept 2010

7. Terminal Procedure Coding
Procedure identified as SID, STAR or APCH
Only one STAR allowed per route
ENRT Transitions used to link STARs to APCHs.
RWY Transitions used to link RWYs to SIDs
Individual legs defined by heading, waypoint, waypoint transition, path terminator, speed constraint, altitude constraint as appropriate
Optional in FMSs: Route Type 3 capability allows
AIXM Procedures Seminar 1-2 Sept 2010

8. Waypoint Transitions Fly-by Fly-over Radius to Fix (RF)
AIXM Procedures Seminar 1-2 Sept 2010

9. RNAV – Path Terminator Leg TypeF
Constant DME arc
Course to
Direct Track
Course from a fix to
Holding pattern
Initial
Constant radius
Track between
Heading to C D H R A I V T C A D F I M R
Altitude
Distance
DME distance
Next leg
Manual termination
Radial termination
Fix
This slide illustrates an example of how PATH + TERMINATOR are used. Not all combinations are implemented by the FAA. In fact, not all combinations are possible in all aircraft navigation database
23 path terminators in ARINC 424 Sup 16 (current)
AIXM Procedures Seminar 1-2 Sept 2010

10. Path Terminators 14 RNAV Types
Course to an Altitude - CA
Course to a Fix CF
Direct to a Fix DF
Fix to an Altitude FA
Fix to a Manual Termination - FM
Racetrack Course Reversal (Alt Term) - HA
Racetrack (Single Circuit - Fix Term) - HF
Racetrack (Manual Termination) - HM
Initial Fix IF
Track to a Fix TF
Constant Radius Arc RF
Heading to an Altitude - VA
Heading to an Intercept - VI
Heading to a Manual Termination - VM
AIXM Procedures Seminar 1-2 Sept 2010

11. Course to an Altitude 090 CA Leg Unspecified Position
Course is flown making adjustment for wind
090
CA Leg
AIXM Procedures Seminar 1-2 Sept 2010

12. A Course to Fix 080 CF Leg Course is flown making adjustment for wind
080 A
CF Leg
Course is flown making adjustment for wind
AIXM Procedures Seminar 1-2 Sept 2010

13. A Direct to Fix Unspecified position Direct DF Leg
AIXM Procedures Seminar 1-2 Sept 2010

14. A Fix to Altitude FA leg is flown making adjustment for wind FA Leg
080
Unspecified A
Position
8000'
AIXM Procedures Seminar 1-2 Sept 2010

15. From a Fix to a Manual Termination
FM leg is flown making adjustment for wind
Radar
Vectors 80
FM Leg A
AIXM Procedures Seminar 1-2 Sept 2010

16. Racetrack A HA - Terminates at an altitude
Previous
Segment
Next A
340
HA - Terminates at an altitude
HF - Terminates at the fix after one orbit
HM - Manually terminated
AIXM Procedures Seminar 1-2 Sept 2010

17. Initial Fix IF A
AIXM Procedures Seminar 1-2 Sept 2010

18. Radius to Fix B RF Leg Next Segment Arc Centre Previous Segment C A
AIXM Procedures Seminar 1-2 Sept 2010

19. Track to a Fix B
TF Leg A
AIXM Procedures Seminar 1-2 Sept 2010

20. Heading to an Altitude No correction made for wind 090 VA Leg
Unspecified
Position
No correction made for wind
090
VA Leg
8000'
AIXM Procedures Seminar 1-2 Sept 2010

21. Heading to Manual Termination
110°
No correction made for wind
VM Leg
Radar
Vectors
AIXM Procedures Seminar 1-2 Sept 2010

22. Examples of FMS leg type capabilty
AIXM Procedures Seminar 1-2 Sept 2010

23. Use Of Path Terminators
Available Path Terminators are defined in PBN Manual Nav Specifications
If the RNAV system does not have leg type demanded by procedure, the data packers have to select one (or combination of) available leg types to give best approximation
Risk incorrect execution!
AIXM Procedures Seminar 1-2 Sept 2010

24. Required Leg Types for RNAV 1 (P-RNAV)
1 automatically execute leg transitions and maintain tracks consistent with the following ARINC 424 path terminators, or their equivalent.
Initial Fix (IF)
Course to Fix (CF)
Direct to Fix (DF)
Track to Fix (TF)
2 automatically execute leg transitions consistent with VA, VM and VI ARINC 424 path terminators, or must be able to be manually flown on a heading to intercept a course or to go direct to another fix after reaching a procedure-specified altitude.
3 automatically execute leg transitions consistent with CA and FM ARINC 424 path terminators, or the permit the pilot to readily designate a waypoint and select a desired course to or from a designated waypoint
AIXM Procedures Seminar 1-2 Sept 2010

25. Advice
Do not attempt to identify Arinc 424 codes for conventional procedures
Frequently RNAV systems cannot follow conventional procedures without careful selection of one (or combination of multiple) leg types
Ensure that only leg types called up in RNAV/RNP spec used
Adequate training needed by procedure designers on leg types
Work with Data houses
AIXM Procedures Seminar 1-2 Sept 2010

26. RNAV Procedure Description
RNAV procedures defined by:
Sequence of waypoints
Identifier
Co-ordinates
Fly-over/fly-by/fixed radius
Path Terminators - ARINC 424
Altitude restrictions
Speed restrictions
Direction of turn
Required navaid
AIXM Procedures Seminar 1-2 Sept 2010

27. What Pilots Need to Know
Waypoint names and sequence
Fly-over/fly-by/fixed radius
Turn direction
Speed restrictions
Altitude restrictions
Required navaid
Leg distance and magnetic track for error checks
Fixes at certain waypoints for gross error checks
AIXM Procedures Seminar 1-2 Sept 2010

28. Procedure Description for Pilots
Waypoint sequence
Fly-over/fly-by/fixed radius
Speed/Altitude Restrictions
Leg distance & magnetic track
Fix information
Turn direction
AIXM Procedures Seminar 1-2 Sept 2010

29. Procedure Description for Database Providers
Textual description provide formal statement of procedure
Often open to interpretation
RNAV procedures require more specific details including path terminators
Can result in lengthy descriptions
Alternative descriptive methods have been developed by IFPP (OCP) and adopted by ICAO
Tabular layout
Formalised textual description
Formalised short-hand description
AIXM Procedures Seminar 1-2 Sept 2010

30. Tabular Description RNAV Approach RNAV SID
AIXM Procedures Seminar 1-2 Sept 2010

31. Formalised Description
Climb on track 047° M, at or above 800ft, turn right [A800+; M047; R]- FA
Direct to ARDAG at 3000ft ARDAG[A3000]- DF
To PF035 at or below 5000ft, turn left -PF035[A5000-;L]- TF (Fly-over)
To OTR on course 090°M at 210kts -OTR[M090; K210]- CF
From STO at or above FL100, turn left direct to WW039 at or above FL070, to WW038 at 5000ft
STO[F100+; L]-
TF (Fly-over)
WW039[F070+]- DF
WW038[A5000] TF
AIXM Procedures Seminar 1-2 Sept 2010

32. Final Approach Segment (FAS) Data Block
For SBAS and GBAS procedures
SBAS FAS in on board Data base
GBAS FAS uplinked on GBAS Datalink
Ensures data not changed between validation and use
Consists of data + Integrity Field (CRC
AIXM Procedures Seminar 1-2 Sept 2010

33. SBAS FAS DB contents Operation type 2 characters Unsigned integer
Service provider identifier 2 characters Unsigned integer
Airport identifier 4 characters Alphanumeric
Runway 5 characters Alphanumeric
Approach perf designator 1 character Unsigned integer
Route indicator 1 character Alpha
Reference path data selector 2 characters Unsigned integer
Reference path ID (Aprch ID) 4 characters Alphanumeric
LTP/FTP latitude 11 characters Alphanumeric
LTP/FTP longitude 12 characters Alphanumeric
LTP/FTP ellipsoidal height 6 characters Signed Integer
FPAP latitude characters Alphanumeric
FPAP longitude 12 characters Alphanumeric
Threshold crossing height 7 characters Alphanumeric
TCH units selector (m/ft) 1 character Feet or meters
Glide path angle (GPA) 4 characters Unsigned integer
Course width at threshold 5 characters Unsigned integer
Length offset 4 characters Unsigned integer
Horizontal alert limit (HAL) 3 characters Numeric
Vertical alert limit (VAL) 3 characters Numeric
AIXM Procedures Seminar 1-2 Sept 2010

34. Integrity Field Enables validation of integrity
Use 32 bit CRC calculated using binary representation
The avionics, when using FAS data block, must compare the resulting CRC remainder with the value provided by the procedure designer.
If the values do not match, the FAS data block will not be used.
Produced by validated software
One such available on ecacnav.com
AIXM Procedures Seminar 1-2 Sept 2010

35. RNAV Procedure Data Tabular description Formalised Description
FAS Data Block
All to be provided on verso side of chart
AIXM Procedures Seminar 1-2 Sept 2010

36. Consistency with FMS/RNAV capabilty
Not all rules are in PANS OPS
What is allowed in PANS OPS (or at least not disallowed) may not be possible to code
Not all FMS/RNAV can use all allowed leg types
AIXM Procedures Seminar 1-2 Sept 2010

37. Example
AIXM Procedures Seminar 1-2 Sept 2010

38. Consistency with FMS/RNAV capabilty
Not all rules are in PANS OPS
What is allowed in PANS OPS (or at least not disallowed) may not be possible to code
Not all FMS/RNAV can use all allowed leg types
Do not expect Procedure designers to know all nuances of RNAV/FMS
Encourage closer working with Data houses
AIXM Procedures Seminar 1-2 Sept 2010

39. Questions?
AIXM Procedures Seminar 1-2 Sept 2010