EPN, seminar AFIS, september 2013 Instrument approach procedures, PBN, GNSS By Frédéric BOISARD, AFIS-O at Cholet LFOU Thanks to Mrs Morgane BARDIEUX (DGAC DSAC/O) and to Mrs Corinne BOUSQUET (DGAC - DSNA/DTI) for their help, assistance and the use of Mrs BOUSQUET's presentation at UAF on december 2012 www.developpement-durable.gouv.fr
IAP : Instrument Approach Procedure What for? Provide pilot/aircraft a track/path ensuring clearance with all obstacles ( natural and human-made) when flying IMC Caracteristics : - segments with specified track and minimum altitude - minimas : visibility and Minimum Descent Altitude (MDA) or Decision Altitude (DA)
A typical IAP
Instruments Approach Procedures : a classification
exemple
IAP : pilot's operations To perform an approach, the visibility and/or RVR must be above the requested minima Arriving at the MDA/DA or MAPt : - if the pilot hasn't got visual references or if he got visual references, but the plane's position can't ensure a safe landing, then the pilot must go around and follow the missed approach procedure - if the pilot has got visual references, then he can continue for landing
IAP with horizontal guidance only : MDA
IAP with horizontal and vertical guidance : DA (simplified version)
Horizontal guidance vs vertical guidance : minimas
NDB/VOR vs GNSS Exemple : Cholet (LFOU) Red : NDB Blue : GNSS Primary and secondary areas wider for NDB than GNSS : less obstacles taken into consideration in GNSS
NDB / VOR vs GNSS Benefits of the GNSS - no maintenance of ground stations - no joining overhead the airfield (useful in case of aerobatics, parachute jumping, winch gliders,...)
Conventional Navigation Navigation using information from ground stations VOR NDB DME ILS/MLS Code AC2
constraints Ground maintenance Scheduled calibration flight Ground stations maintenance Stations renewal Localisation Coverage
Conventional navigation limits Tracks concentration (tracks converging towards ground stations) Utilisation of ground stations performances and not (or a little) of plane's navigation ability Unappropriate to some areas (mountainous) No vertical guidance (safety consequences)
PBN : Performance Based Navigation A new navigation concept (ICAO Doc 9613 ) No requirement concerning how the plane flies, nor which type of sensor is used to know the plane position, and to follow a path Requirements concerning plane's navigation system performances Positioning precision Navigation : what is the plane able to do? Which type of path can he follow? Crew requirements
Navigation PBN Not characterized by the type of ground stations used Navigation from point A (Lat, Long) to point B (Lat, Long): Airplane calculate its position using ground stations calculate its position using navigation satellites fitted with navigation device allowing flight from A to B Acceptable navigation solution if : Calculate position with a precision coherent with the phase of the flight (accuracy) Reliance on this calculated position (integrity) Availability of this navigation solution when needed (continuity).
PBN : navigation specifications Each navigation sensor has a navigation specification Different navigation specifications are : - RNAV : area NAVigation - RNP : Required Navigation Performance - RNP AR : RNP Authorization Required
navigation specification: RNAV vs RNP Common points Permanent indication of the plane's GPS location in comparison with the plane's expected path Display of distance and heading to the next way-point (WP) Display of ground-speed and flight-time to the next way-point Use of navigation database Indication of navigation system failure
navigation specification: RNAV vs RNP differences Navigation Specification RNP Navigation performances monitoring function and Alerting function Navigation Specification RNAV No requirement concerning performances monitoring and alerting
navigation specifications and navigation sensors
PBN navigation specifications precision required (Nm) APCH: ApproaCH AR: Authorisation Required
Navigation Specifications associated to airspaces OCEANIC REMOTE RNP4 RNAV10 EN ROUTE RNAV5 RNAV2 RNAV1 TERMINAL BASIC RNP1 RNAV2 RNAV1 APPROCHE RNP APCH RNP AR Code AC2
GNSS Concept EGNOS GLONASS geostationary satellite(sbas) WAAS MSAS GPS Augmentation From ground (GBAS) GAGAN GALILEO Satellites constellations On board (ABAS) R.A.I.M A.A.I.M ABAS : Aircraft Based Augmentation System SBAS : Satellite Based Augmentation System GBAS : Ground Based Augmentation System GNSS : Global Navigation Satellite System RAIM : Receiver Autonomous Integrity Monitoring AAIM : Aircraft Autonomous Integrity Monitoring
Augmentation systems ABAS : On board equipments with integrity monitoring No precision improvment GBAS: Integrity monitoring / precision improved covers an area 25 NM around airport SBAS : Integrity monitoring precision improved Covers a large area
Approach : PBN vs Conventional ICAO Classification NPA non precision approaches APV Approaches with vertical guidance PA precision approaches Conventional procedure RNP APCH RNP APCH conventional procedure RNAV with lateral and vertical guidance VOR/DME NPA GNSS APV Baro APV SBAS ILS PA GBAS NDB MLS Localizer PAR LNAV LNAV/VNAV LPV GLS PBN Vertical guidance on APV approaches is less performant than guidance required for precision approaches. 29
Guidance on final
Focus on approach GBAS NPA APV PA CAT I, II/III LNAV LNAV/VNAV LPV CAT I, II/III
Equipment and final path Plane with GPS receiver Plane with GPS receiver and VNAV function Plane with SBAS receiver and appropriate navigation systm
APV BaroVNAV Benefits At present time system widely existing on planes (ca. 80% of Paris- CDG traffic) Limitations Costly system Technical Problems : Altimeter setting error (QNH) QNH given by the ground false or not updated Omission of new setting when passing transition level Unit mistake (mb vs. Inches) Non-standard atmosphere certif. FMS, database
APV SBAS Benefits Excellent horizontal and vertical guidances Can replace some ILS Limitations At present time few planes concerned (Business Jets and regional aviation)