NAV11.1 — Implement precision approach procedures using GBAS CAT II based on GAST C
In current ILS Cat II operations there is a need to protect the ILS critical and sensitive areas which result in restricted ground movements and extra spacing margins between aircraft in order to accommodate the longer runway occupancy times (ROT) through the need to protect the larger ILS sensitive area. At capacity constrained airports this may lead to flights being diverted or even cancelled. In addition, this is typically also associated with longer flight times, i.e. more fuel being used.
This objective proposes the use of GBAS which has limited (GBAS Local Object Consideration Areas) or no protection areas, usually located outside aircraft movement areas. This allows the reduction of runway occupancy times in low visibility conditions resulting in reduced spacing between arrival aircraft. The amount of runway throughput gained depends on wake turbulence separation and any other additional spacing needs. With a proper siting of the GBAS ground equipment (compliant with the GBAS Local Object Consideration Areas), there’s no need for critical/sensitive areas.
Use of GBAS GAST C for CAT II enables:
a) flexible approaches; synergistic with RNAV/RNP, PA where ILS cannot due to geography, signal stability (immune to signal bends inherent in ILS);
b) complement ILS at airports with multiple RWYs during LVP;
c) the rationalization of some ILS thus reducing operation and maintenance costs and optimizing spectrum;
d) PA at aerodromes without SBAS coverage or where PA performances cannot be achieved with SBAS.
Benefits of using GBAS in Low Visibility Conditions include improved resilience of airport capacity with fewer flight cancellations due to LVP in force. GBAS GAST C for CAT II will enable runway ends which are not ILS CATII equipped to be used for CATII operations as long as the runway is CATII qualified. This will have positive effects on gaseous emissions, i.e. less CO2.
NOTE: The benefits mentioned are only gained if a sufficient number of aircraft are qualified; therefore, an action should be included to verify upgradeability of existing aircraft equipage, promote further airborne equipage, monitor aircraft equipage rate and qualification and assess incentives.
NOTE FOR MILITARY AUTHORITIES: It is the responsibility of each Military Authority to review this Objective IN ITS ENTIRETY and address each of the SLoAs that the Military Authority considers RELEVANT for itself. This has to be done on top and above of the review of "MIL" SLoAs which identify actions EXCLUSIVE to MIL Authorities.
- Edition
- 2022
- Stakeholders
- Regulator / Air Navigation Service Provider / Airspace Users
- Type
- SESAR
- Scope
- Local
- Status
- Active
Links to SESAR Solutions
Links to PCP ATM Sub-Functionalities
ICAO Block Modules: Expected Performance Benefits
- Safety
- Safety of approach, landing and guided-take-off operations based on GBAS GAST C CAT II are as safe as operations based on ILS CAT II assuming the identified safety requirements are met. GBAS improves safety in the segment of avoiding a scenario of false LOC or Glide beam capture.
- Capacity
- GBAS has limited (GBAS Local Object Consideration Areas) or no protection areas, usually located outside aircraft movement areas. This allows the reduction of runway occupancy times in low visibility conditions resulting in reduced spacing between arrival aircraft. The amount of runway throughput gained depends on wake turbulence separation and any other additional spacing needs.
- Operational efficiency
- Fewer flights will be cancelled or diverted saving the Airspace User (Main and Regional airliners) associated costs. To be noted that cancellations also affect the subsequent legs planned with those aircraft. Business Aviation see minimal benefits as they fly infrequently to capacity constrained airports during LVP. Avoiding the loss of runway capacity will reduce the level of delay and avoid the associated costs. A key issue is the impact of the primary delays on the subsequent legs to be performed by those aircraft which try to absorb the delay where possible. Higher glide slopes than those possible with ILS, 3.2° even in CAT II weather conditions. Many fielded avionics and ground systems are upgradeable with limited effort
- Cost efficiency
- One GBAS station can provide approaches for multiple runway end as well as multiple approaches per runway end. The GBAS station in the long term is much more cost efficient than the ILS in terms of less maintenance and flight inspection required.
- Environment
- The environmental benefits come from the saving of jet fuel due to the resilience of the system in keeping its capacity even in Low Visibility Operations. Fuel savings results in direct reductions in CO2 emissions. There is also a direct benefit in term of local air quality by having less aircraft queuing on the runway for departure conditions. Noise abatement.
- Security
- -
Supporting Material
| Title | Related SLoAs |
|---|---|
|
EASA - CRI F-27 issue 2 for CAT II operations |
USE01 |
|
EUROCAE - ED-114B - MOPS For Global Navigation Satellite Ground Based Augmentation System Ground Equipment to support Precision Approach and Landing 09/2019 https://eshop.eurocae.net/eurocae-documents-and-reports/ed-114b/ |
ASP01, ASP02, USE02 |
|
ICAO - Annex 10 - Aeronautical Telecommunications |
ASP01 |
|
ICAO - Doc 8168-Volume II - Aircraft Operations - Volume II - Construction of Visual and Instrument Flight Procedures - Edition 5 / 11/2011 |
ASP02 |
|
ICAO - EUR-Doc 013 - Guidance Material on All Weather Operations at Aerodromes |
ASP02 |
|
ICAO - NSP JWG7 WP19 - Concept for GBAS Cat II Operations using ICAO GAST-C 04/2021 |
ASP01, ASP02, REG01, USE02 |