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RNAV Procedures. 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
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RNAV Procedures AIXM Procedures Seminar 1-2 Sept 2010
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
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
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
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
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
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 AIXM Procedures Seminar 1-2 Sept 2010
Waypoint Transitions Fly-by Fly-over Radius to Fix (RF) AIXM Procedures Seminar 1-2 Sept 2010
RNAV – Path Terminator Leg Type Altitude A Constant DME arc A Distance C C Course to DME distance D D Direct Track Fix F F Course from a fix to Next leg I Holding pattern H Manual termination M I Initial Radial termination R R Constant radius T Track between V Heading to Terminator Path AIXM Procedures Seminar 1-2 Sept 2010
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
Unspecified Position Course to an Altitude Course is flown making adjustment for wind 0 090 CA Leg AIXM Procedures Seminar 1-2 Sept 2010
Course to Fix 0 080 A CF Leg Course is flown making adjustment for wind AIXM Procedures Seminar 1-2 Sept 2010
Direct to Fix Unspecified position Direct DF Leg A AIXM Procedures Seminar 1-2 Sept 2010
0 080 Fix to Altitude FA leg is flown making adjustment for wind FA Leg Unspecified Position A 8000' AIXM Procedures Seminar 1-2 Sept 2010
From a Fix to a Manual Termination FM leg is flown making adjustment for wind Radar Vectors 0 80 FM Leg A AIXM Procedures Seminar 1-2 Sept 2010
Next Segment A 340 0 Previous Segment Racetrack HA - Terminates at an altitude HF - Terminates at the fix after one orbit HM - Manuallyterminated AIXM Procedures Seminar 1-2 Sept 2010
Initial Fix IF A AIXM Procedures Seminar 1-2 Sept 2010
Radius to Fix RF Leg C B Next A Segment Arc Centre Previous Segment AIXM Procedures Seminar 1-2 Sept 2010
Track to a Fix B TF Leg A AIXM Procedures Seminar 1-2 Sept 2010
Heading to an Altitude Unspecified Position No correction made for wind 0 090 VA Leg 8000' AIXM Procedures Seminar 1-2 Sept 2010
Heading to Manual Termination No correction made for wind 110° VM Leg Radar Vectors AIXM Procedures Seminar 1-2 Sept 2010
Examples of FMS leg type capabilty AIXM Procedures Seminar 1-2 Sept 2010
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
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
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
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
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
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
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
Tabular Description RNAV Approach RNAV SID AIXM Procedures Seminar 1-2 Sept 2010
STO[F100+; L]- TF (Fly-over) WW039[F070+]- DF WW038[A5000] TF 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 AIXM Procedures Seminar 1-2 Sept 2010
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
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 AIXM Procedures Seminar 1-2 Sept 2010
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
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
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
Example AIXM Procedures Seminar 1-2 Sept 2010
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
Questions? AIXM Procedures Seminar 1-2 Sept 2010