AIXM Procedures Seminar 1-2 Sept 2010 1 RNAV Procedures

AIXM Procedures Seminar 1-2 Sept 2010 1

RNAV Procedures


Conventional Procedure DescriptionConventional 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


RNAV Procedure DescriptionRNAV 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


Coding the ProcedureCoding 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.


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


En-Route Coding

• Individual airway legs defined by waypoint and altitude constraints

• En-route holds not associated with any aerodrome and identified as ‘ENRT’


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


Fly-by

Fly-over

Radius to Fix (RF)

Waypoint TransitionsWaypoint Transitions


RNAV – Path Terminator Leg Type

TerminatorPath

CA

DFI

MR

Altitude

Distance

DME distance

Next leg

Manual termination

Radial termination

FixF

Constant DME arc

Course to

Direct Track

Course from a fix to

Holding pattern

Initial

Constant radius

Track between

Heading to

CD

H

R

A

I

VT


Path Terminators 14 RNAV TypesPath 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


Course to an Altitude

UnspecifiedPosition

090

CA Leg

0

Course is flown making adjustment for wind


CF Leg

0800

A

Course to FixCourse to Fix

Course is flown making adjustment for wind


DirectDF Leg

Unspecified position

A

Direct to FixDirect to Fix


AUnspecified

Position

8000'

FA Leg

0800

Fix to AltitudeFix to Altitude

FA leg is flown making adjustment for wind


From a Fix to a Manual Termination

80

AFM Leg

RadarVectors0

FM leg is flown making adjustment for wind


Racetrack

Previous

Segm

ent

Next

Segm

entA

340 0

HA - Terminates at an altitude

HF - Terminates at the fix after one orbit

HM - Manually terminated


Initial Fix

IF

A


Pre

viou

sS

egm

ent Arc

Centre

NextSegm

entA

C

B

RF Leg

Radius to Fix


Track to a Fix

TF Leg

A

B


Heading to an Altitude

UnspecifiedPosition

090

VA Leg

8000'

0

No correction made for wind


110°

VM Leg

RadarVectors

Heading to Manual TerminationHeading to Manual Termination

No correction made for wind


FMSS/W version U5.0 U7.5 U10.7 SCN 15/16

101-320SCN

405/505 600/700

SCN 601+/701+

SCN 801+/901+

Year 1990 1997 2007 2001Take-off update yes yes yes yes yes yes yes

GPS no yes yes no yes yes yesDME/DME yes yes yes yes yes yes yes

Intertial yes yes yes yes yes yes yesIF yes yes yes yes yes yes yesTF yes yes yes yes yes yes yesCF yes yes yes yes yes yes yesDF yes yes yes yes yes yes yesFA yes yes yes no yes yes yesFC yes yes yes no yes yes yesFD yes yes yes no yes yes yesFM yes yes yes no yes yes yesCA yes yes yes no yes yes yesCD yes yes yes no yes yes yesCI yes yes yes no yes yes yesCR yes yes yes no yes yes yesRF no no yes no no no yesAF no no yes no yes yes yesVA yes yes yes no yes yes yesVD yes yes yes no yes yes yesVI yes yes yes yes yes yes yesVM yes yes yes yes yes yes yesVR yes yes yes no yes yes yesPI no yes yes no yes yes yes

HA, HF, HM (holding) HM only HM, HF HM, HF no no yes yesFRT no no yes no no no no

MAINLINE: GE FMS REGIONAL: Universal FMS

Examples of FMS leg type capabilty


Use Of Path TerminatorsUse Of Path TerminatorsUse Of Path TerminatorsUse 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!


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


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


RNAV Procedure DescriptionRNAV Procedure DescriptionRNAV Procedure DescriptionRNAV 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


What Pilots Need to KnowWhat Pilots Need to KnowWhat Pilots Need to KnowWhat 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


Procedure Description for Procedure Description for PilotsPilotsProcedure Description for Procedure Description for PilotsPilots

Waypoint sequence

Fly-over/fly-by/fixed radius

Speed/Altitude Restrictions

Leg distance & magnetic track

Fix information

Turn direction


Procedure Description for Procedure Description for Database ProvidersDatabase ProvidersProcedure Description for Procedure Description for Database ProvidersDatabase 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


RNAV Approach

RNAV SID

Tabular DescriptionTabular DescriptionTabular DescriptionTabular Description


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

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

Formalised DescriptionFormalised Description


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


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 11 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


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


RNAV Procedure Data

• Tabular description • Formalised Description• FAS Data Block

All to be provided on verso side of chart


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


Example


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


Questions?

Documents

AIXM Procedures Seminar 1-2 Sept 2010 1 RNAV Procedures