Brussels blocking UK from using EGNOS for LPV - and selection of alternates, and LPV versus +V

Yes, I am sure the signal will be maintained, since e.g. the Channel Islands retain their LPV approaches, since they have a direct deal with Brussels.

@PeteD post moved to existing thread on this topic.

Peter wrote:

Yes, I am sure the signal will be maintained

Hypothetically, EGNOS ground stations could be shut down to remove EGNOS coverage in the UK, but I understand that’s not possible without simultaneously degrade EGNOS performance in surrounding areas.

PeteD wrote:

LNAV,LNAV/VNAV,LPV approaches are all included on the same RNP approach plate, with different minima.

Like wise, there is only one RNP approach for them in the database, usually named RNAV xxgps LPV(or similar)

So apart from a possible name change( which hasn’t happened this month) will the coding change?
I.E.how is it different for an LPV?

The correction and integrity data is what is broadcast by the EGNOS satellites and it covers the entire area, so it will remain unchanged and it would be totally impractical to do otherwise. There will be no name changes for any approaches, but the published minimums in the UK will not include LPV op[tion. The database will be updated to reflect the available minimums of LNAV and LNAV/VNAV, so the GPS navigator will annunciate LNAV/VNAV or LNAV as appropriate. An LPV procedure includes a FAS datablock which defines the final approach segment and specifies the runway, the relevant points on the final, the required integrity for the procedure (VAL of 35 meters for LPV200 and 50 meters for LPV) and a checksum. The FAS datablock will be removed from the database as it is only required for the LPV procedure. There is no need to rename the procedure because the PBN Nav Specification for RNP APCH encompasses LNAV, LNAV/VNAV, LPV, and LP minimums. Here is the US, the procedure names are RNAV (GPS) for RNP APCH and one is cleared for the RNAV RWY XX approach and not for a specific minimum, so if the approach supports LNAV, LNAV/VNAV, or LPV, the controller has no idea which the pilot is choosing to use.

Airborne_Again wrote:

Hypothetically, EGNOS ground stations could be shut down to remove EGNOS coverage in the UK, but I understand that’s not possible without simultaneously degrade EGNOS performance in surrounding areas.

This would degrade EGNOS service for the entire system and UK would still get the same broadcast signal anyway as the rest of the service volume. It would not be practical or necessary or achieve the desired result.

NCYankee, many thanks for your comprehensive explanation to my question!
So the FAS datablock just checks for the required integrity and makes any relevant lpv announcements?
Otherwise the coding for the various(lpv, LNAV etc) is identical?

ARINC 424 is the standard that defines database encoding, including approaches. The 424 record describes the paths and other information including the service levels supported by the RNAV procedure. that is LNAV, LNAV/VNAV, LPV, LPV200, LP. When an RNAV approach is encoded that requires SBAS, such as LPV or LP, an additional block is specified for the Final Approach Segment called the FAS Data Block. An approach with only LNAV and/or LNAV/VNAV does not require a FAS Data Block to be specified. Only a single FAS Data Block may be specified for a given approach. To make sure that the FAS Data Block that is used by the navigator has not been modified from the values generated by the procedure designer all the way to the usage in a navigator to conduct an approach, the FAS Data Block includes a 32 bit CRC remainder that must be validated. The data included in the FAS Data Block includes:

Operation Type code
SBAS Service Provider Identifier
Airport Identifier
Runway
Approach Performance Designator
Route Indicator
Reference Path Data Selector
Reference Path Identifier (Approach ID)
LTP/FTP Latitude
LTP/FTP Longitude
FPAP Latitude
FPAP Longitude
Threshold Crossing Height (TCH)
TCH units selector
Glidepath Angle (GPA)
Course Width at Threshold
Length Offset
Horizontal Alert Limit
Vertical Alert Limit
CRC Remainder

The LNAV and LNAV/VNAV don’t need this data as the information is contained in the rest of the ARINC 424 record and the lateral guidance is much broader (+/- 0.3 NM). The HAL value is fixed at 556 meters for both the LNAV and LNAV/VNAV and the VAL is 50 meters for the LNAV/VNAV. With the LPV, HAL is fixed at 40 meters and VAL is either 50 meters for LPV standard service and 35 meters for LPV200 service.

LPV map now updated to exclude the UK.

Clearly somebody has been specially assigned to let everybody know. For years this map showed loads of LPV approaches which didn’t exist and nobody was bothered

It has been revealed in a govt hearing that the cost of staying a member of EGNOS was €30-35m per year. The figure was announced by Lord Callanan, of the Department for Business, Energy and Industrial Strategy, in answer to a question from Lord (Tony) Berkeley.

Peter wrote:

It has been revealed in a govt hearing that the cost of staying a member of EGNOS was €30-35m per year.

Yearly budget of the EGNOS program is in the ballpark of 900m – so 30-35m sounds like a bargain…