GNSS Precision Approaches

Ajouter 

sigle 

DCS 

Implementation of RNAV 

approaches in France 

Implementing RNP workshop 

SESSION 2: RNAV – THE FIRST STEPS 

B. Roturier (DGAC/DSNA - Direction de la Technique et de 

I’Innovation/Sous Direction des Systémes Opérationnels), 

B. Rabiller (DGAC/DCS – Sous Direction de la Navigabilité et des 

Opérations) 

Toulouse, 5-6 October 2005

• RNAV Approaches context 

Items 

• GNSS Non Precision Approaches (NPA) 

• GNSS Approaches with Vertical guidance (APV) 

• GNSS Precision Approaches (Cat I) 

• Synthesis 

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RNAV Approaches context 

RNP and RNAV approaches 

• The RNP concept for approach and landing operations, its 

relation with RNAV and the requirements for operational 

implementation are currently not fully defined and harmonized 

worldwide. 

• The ICAO study group RNPSORSG is currently progressing on 

this item: 

– The updated RNP concept for approaches should accommodate all 

performance based operations, including those supported by linear and 

angular guidance. 

• Approach and landing operations supported by GNSS are 

performance based operations, 

– (see next slide) 

-3-


GNSS performance requirements 

ICAO GNSS signal performance requirements 

NPA 

NPA BaroVNAV 

APV I and APV Baro-VNAV 

APV II Cat I 

50 m (5σ) 

20 m (5σ) 10 m(5σ) 

40 m 556 m (5σ) 

Not to scale! 

?? m 

?? σ 

-4-


French activities 

• Since several years, a steering committee supporting the 

implementation of RNAV in final approach in French airspace 

has assessed the benefits/limitations of different technologies 

for RNAV performance based operations: 

• Performance based RNAV operations: 

– NPA with GNSS 

– NPA with GNSS and BaroVNAV continuous descent 

– APV BaroVNAV 

– APV I&II with GNSS 

– Cat I with GNSS 

• Technologies: 

– GNSS ABAS (stand alone & multisensors), SBAS, GBAS, BaroVNAV,… 

-5-


French activities 

• The steering committee is supported by DGAC experts from 

different directorate: 

– procedure design, infrastructure, aeronautical information services, aircraft 

certification & operations, regulation, flight inspection, etc… 

• The SC work has led DSNA to recommend a strategy for RNAV 

deployment within French airspace. The French regulator, 

DAST, will endorse it shortly. 

• The main findings of the steering committee and the associated 

implementation programme concerning RNAV in final approach 

is summarized here. 

-6-

• RNAV GNSS Approaches context 

Items 




• Synthesis 

-7-

• Benefits assessment 

– Straight approaches for all runway ends 

• Safety benefits 

RNAV NPA GNSS 

benefits vs. limitations 

– Lower lateral dispersion than conventional navaids NPA 

• Thanks to GNSS improved precision 

• Limitations assessment 

– Lack of vertical guidance has negative impacts on safety 

• Accident and major incidents have occurred these last years in 

France on NPA with conventional Navaids. 

– Absence of vertical guidance was judged an important factor. 

• BaroVNAV may improve safety as an advisory system to fly 

Constant Descent Final Approach to, but most BaroVNAV 

systems (AC 20-129) do not require integrity 

– Altimetry issues (similar to non RNAV NPA) 

– Database integrity issues 

Other Causes 

80% 

CFIT statistics 

1988-97 

(source Honeywell) 

-8- 

Altimetry Error 

Suspected 

20%


implementation 

• Conclusion was that there are potential safety benefits in 

implementing NPA RNAV based on GNSS to allow simpler, 

repeatable approach trajectories for all airspace users. 

• RNAV Approaches steering committee activities: 

– Reviews of the requests and the prioritisation of procedure publication 

– Coordination with users 

– 40 procedures are planned to be published in the next 3 years 

• The advisory use of vertical guidance with BaroVNAV on NPA is 

accepted: 

• Some remaining issues have to clarified (e.g. use of DA vs. MDA), but not identified 

today as a blocking point. 

⇒Implementation of GNSS NPA, with BaroVNAV vertical guidance 

as an option, is the first step of the DSNA strategy for RNAV 

approaches. 

⇒The identified limitations are to be solved within the 2 nd step 

-9-


Typical Approach Chart 

-10-


Items 




• Synthesis 

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RNAV APproaches with 

Vertical guidance (APV) 

• ICAO recommends large scale deployment of APV: 

– 11th Air Navigation Conference (2003) 

• Recommends APV I implementation worldwide 

– Annex 10 strategy for approach & landing (2005) 

• Two technologies are available for vertical guidance on APV: 

– BaroVNAV ( operations known as APV baroVNAV) 

• Most systems flying today have been certified under AC 20-129 (1988) 

– GNSS vertical guidance (operations known as LPV, supported by 

APV I&II performance requirement) 

• SBAS (WAAS (US/Canada/Mexico), EGNOS (Europe), etc..), 

• GBAS/GRAS (Australia) 

• Galileo (worldwide - in the future) 

-12-

APV BaroVNAV 

vs. NPA BaroVNAV 

MDA or DA 

• APV BaroVNAV aims at lower operational minima with reduced 

obstacle separation wrt NPA BaroVNAV 

• BaroVNAV has to be used as a primary navigation system in APV, 

whereas advisory use only is required in NPA 

⇒APV baroVNAV requires a specific safety assessment 

DA 

-13-


APV BaroVNAV 


– BaroVNAV exists on a large number of aircrafts (~80% of Paris CDG aircraft) 


– Most equipped aircrafts are certified for an advisory use only (AC 20-129) 

• The aircraft certification requirements to implement the new ICAO PANS OPS APV 

BaroVNAV criteria are unknown 

– Discussed recently within JAA, under AMC – 20XX elaboration 

– BaroVNAV Integrity issues 

• Increased issues wrt NPA BaroVNAV due to obstacle clearance reduction: 

– Wrong altimeter setting, wrong or outdated QNH transmitted by ATC … 

• DSNA assessment is that APV BaroVNAV integrity issues require appropriate 

mitigation technique: 

– But still unidentified at this stage 

⇒ Due to aircraft certification open issues and lack of identified 

integrity mitigation techniques, DGAC has decided not to authorize 

APV BaroVNAV publication 

-14-

APV I&II 



– Identification of runway ends where an operational benefit for APV I&II 

is expected: 

• Main airports (ex. Paris CDG), Middle sized airports (ex. Lille), Small airports 

(ex. Dinard), Sites with environmental constraints (ex. Nice), Helicopters,… 

– APV I (with EGNOS in this study) improves the approach operational 

context, and allow to reduce minima (250 ft – obstacles permitting) 

• Similar results were obtained in the USA (APV I WAAS) and in 

Australia(APV I GRAS), expected to be valid also with future Galileo APV I&II 

– Database integrity issue is solved 

• Final Approach Segment data block protected by a Cyclic Redundant Code 

– ILS look alike operational concept and integrity (xLS) – minima 250 ft 

– All users may have access to the technology 


– Approaches supported by APV I&II is a new performance based 

operation 

• Requires an airborne upgrade, issues with users equipment rate 

• Requires a qualified GNSS system – expected 2007 for EGNOS 

-15-

APV I&II 

implementation 

• Conclusion is that APV I &II performance based operations allow 

to fulfil most safety & performance requirements for RNAV for 

approaches. 

• Current DGAC implementation strategy is: 

– to break the user equipment chicken and egg loop by upgrading RNAV 

GNSS NPA procedures to APV I supported by EGNOS – the first system to 

support APV I&II performance level in Europe. 

– develop partnership with aircraft/helicopter manufacturers and operators 

• Galileo should also support APV I&II in the future 

– but when will an aviation qualified Galileo be available: 2012?… 2015?… 

⇒ An EGNOS APV I implementation WG has been set up by DSNA 

in 2004. Target is: 

– first procedure publication in 2007, 

– all GNSS NPA procedures upgraded to APV I 

-16-

Typical RNAV future approach 

chart 

LPV: minima APV I&II SBAS 

(EGNOS, WAAS,…) 

-17- 

LNAV/VNAV: minima APV BaroVNAV (if 

supported!) 

LNAV: minima GNSS NPA


Items 




• Synthesis 

-18-

GNSS Precision Approaches 

GBAS Category I 

• The business case for GBAS Cat I, which was very promising 10 

years ago, is now limited since : 

– There is still a high density of conventional navaids (ILS in particular) 

– SBAS brings close operational performance with APV I&II performance 

levels 

– The evolution of GBAS CAT I toward CATII/III is not yet clearly defined 

– The FAA deployment program initially planned for 2006 has been delayed. 

• DSNA activities for GBAS Cat I: 

– support Airbus certification, 

– prepare possibly a few stations installations (TBC), in overseas territories 

– support Cat II/III standardisation 

-19-

GNSS Precision 

Approaches 

GBAS Category I 

-20-


Items 




• Synthesis 

-21-

Synthesis 

• Since 2000 DSNA has assessed different performance based 

operations to support RNAV for approach & landing operations. 

• In 2005 DSNA has proposed the following strategy for RNAV 

approaches implementation: 

– RNAV with GNSS NPA as a first step, 

• BaroVNAV may be used as an advisory system to improve safety 

– RNAV with GNSS APV I as a second step, 

• In line with ICAO strategy, GNSS geometric vertical guidance will allow to 

improve safety and airport accessibility wrt NPA. 

• EGNOS is the first system in Europe to support APV I performance 

– Requires a qualified EGNOS system & EGNOS operator (expected 2007) 

– The users equipment rate toward EGNOS/WAAS receivers is a major issue 

– No APV BaroVNAV implementation currently planned, 

– GBAS CAT I ground stations might be deployed on some overseas, 

airports (TBC) 

• Cat I implementation allows to support Cat II/III standardisation 

-22-

Backup Slides 

-23-

RNAV GNSS Approaches 

context 

ICAO GNSS augmentations 

Geostationary Satellite 

Based Augmentation System 

(SBAS) 

GALILEO 

(TBD) 

Ground Based 

Augmentation System 

(GBAS) 

GNSS 

GPS 

GLONASS 

Aircraft Based 

Augmentation System 

(ABAS) 

-24-


context 

ICAO Classification 

• ICAO Approaches definition: 

– Non Precision Approach (NPA) 

• Lateral Guidance Only 

– But Barometric Vertical guidance (FMS) may be used as an advisory system to fly CDFA 

– APproach with Vertical guidance (APV) 

• Lateral and Vertical Guidance 

• Two basic technologies can be used: 

– Barometric vertical guidance, with NPA like GNSS lateral guidance 

(APV/Baro-VNAV) 

– GNSS vertical guidance, with two performance levels, including improved Localizer like 

performance for lateral guidance 

(APV-I, APV-II) 

– Precision Approach (PA) 

• Lateral and Vertical Guidance 

• Three performance levels (Cat I, Cat II, Cat III) 

-25-

NPA 

Non Precision Approaches 

Conventional 

Navaids 

VOR/DME 

NDB 

Localizer 

... 


context 

RNAV 

GNSS ABAS 

DME/DME 

APV BaroVNAV 

GNSS ABAS 

DME/DME 

+ 

BaroVNAV vertical 

ICAO Classification 

ICAO 

Classification 

APV 

APproaches with Vertical guidance 

RNAV 

APV I&II 

GNSS SBAS 

GNSS GBAS 

GNSS Galileo 

... 

Conventional 

Navaids 

ILS 

MLS 

PAR 

PA 

Precision Approaches 

RNAV 

GNSS GBAS 

... 

-26-

Statistical distribution of 

minima based on a US study 

• Minima (HAT) results for LPV(SBAS APV I), LNAV-VNAV (APV Baro-VNAV) and 

RNP approaches at 1534 US airports 

-27-

The APV implementation study in 

France - Status of work in Dec 2003 

Airport QFU APV 1 

operationa 

l gain 

Paris le 

Bourget 

07 ILS 

Backup 

Paris CDG 26 L ILS Backup 

Keeping 

parallel 

runway 

capability 

Nice 04R environmen 

tal 

Montpellier 13L Air France 

List 

Approach 

procedure 

Glide 

Slope 

Angle 

OCH 

Cat D 

Gain OCH 

APV 1 

APV1 3° 325 Ft 105 ft 

ILS DME 3° 370 ft / 

VORDME 3° 430 ft / 

APV1 3° 325 ft min 22 ft min 

242 ft max 105 ft max 


LLZ DME 3° 347 ft / 

APV1 3° 279 ft 21 ft 


LLZ DME 3° 300 ft / 

APV1 3° 289 ft 158 ft 

APV1 3.5° 289 ft 158 ft 

VORDME 6.4 % 

3.66° 

447 ft / 

-28-

The APV implementation study 

in France - Status of work in Dec 2003 

Airport QFU APV 1 

operationa 

l gain 

Approach 

procedure 

Glide 

Slope 

Angle 

OCH Gain OCH 

APV 1 

Beauvais 13 Low cost APV1 3° 258 ft 102 ft 

Roanne 20 High slope 

reduction 

Lille 08 Air France 

list 

Nantes 21 Air France 

list 

L VOR 3° 360 ft / 

APV1 3° 250 ft 0 ft (2) 

VOR 6.3 % 3.6° 504 ft / 

APV1 3° 271 ft 167 or 54 ft 

VOR 438 ft / 

VORDME 5.7% 323 ft / 

APV1 3° 276 Ft 81 ft 

VOPRDME 3° 357 ft / 

Pau 13 APV1 3° 220 ft 630 ft 

Biarritz 09 Air France 

list 

MVI 850 ft / 

APV1 3° 248 ft 133 ft 

VORDME 3° 381 ft / 

-29-

Aérodrome QFU APV 1 

operation 

al gain 

Fort de 

France 

The APV implementation study 

in France - Status of work in Dec 2003 

27 Reduce 

slope and 

minima 

Albi 27 Allow 

straight in 

approach 

Mende 13 High slope 

reduction 

Dinard 17 High slope 

reduction 

St Denis 30 High slope 

reduction 

Approach 

procedure 

APV1 Rwy 

27 

APV1 Rwy 

27 

VORDME 

Rwy 27 

Glide 

Slope 

Angle 

OCH Gain OCH 

APV 1 

3° 901 ft 349 ft 

3.5° 901 ft 349 ft 

3.5° 6.1% 1250 ft / 

APV1 rwy 27 3° Cat C 

MVI following 3.2° 

398 ft 

Cat C 

ILS 

890 ft 

APV1 Rwy 

13 

VOR 

/LLZ/DME 

3.5 ° Cat B 

4° 

369 ft 

Cat B 

530 ft 

492 ft 

/ 

161 ft 

APV1 3° 223ft 105 ft 

VOR/DME 4° 328 ft / 

APV1 3.5° 294 ft 435 ft 

VOR/DME 3.7° 729 ft / 

/ 

-30-

Session 2 

RNAV – The First Steps 

Applications 

-31-

GNSS Precision Approaches

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