Addition of new WMO Abbreviated Headings for exchange of VONA reports over ICAO AFS

[blchoy]

Initial request

In the proposed Amendment 81 to ICAO Annex 3, Volcano Observatory Notice for Aviation (VONA) information will need to be exchanged over the ICAO Aeronautical Fixed Service (AFS) as early as 2024. These include Traditional Alphanumeric Code (TAC) and IWXXM VONA reports. AFS is a store-and-forward system like the WMO Global Telecommunication System (GTS) and headers in the form WMO Abbreviated Headings (i.e. TTAAii) is required for proper routing of the messages. Although aviation messages are purely exchanged on AFS, their abbreviated headings are also controlled by WMO No.386 Manual on the Global Telecommunication System. Attachment II-5 of WMO No.386 indicates all TTs being used.

Amendment details

Two new TTs are proposed to be added and associated AAs and iis to be defined. These should cover

1. TAC VONA
2. IWXXM VONA

Comments

The approval process should be completed well before the applicable date of respective SARPs in Amendment 81 to ICAO Annex 3, which is expected to be Nov 2024. It is also understood that a paper will be prepared for WMO INFCOM-3 to be held in mid-2024 proposing the retirement of WMO No.386. Therefore FT2024-1 is probably the last chance of submitting the request for change, and the team should strive for submitting the request for FT2023-2.

Requestor(s)

@blchoy on behalf of ICAO WG-MIE.

Stakeholder(s)

WMO TT-AvData and ICAO WG-MIE.

Publication(s)

WMO No.386 Manual on Global Telecommunication System.

Expected impact of change

MEDIUM

Collaborators

No response

References

Proposed Amendment 81 to ICAO Annex 3 (restricted access).

Validation

No response

[blchoy]

Based on the ICAO APAC ROBEX Handbook, the following TTs are being handled in the regional AFS (Note: Experts are welcomed to enrich this list to cover AFS in other regions, but the intention here is to list out those TTs being used for aviation purpose. The choice of possible combinations of TTs is limited as the TTs have broader scope as documented in WMO No.386):

Data type	Abbreviated Name	TT for TAC (Code Form)	TT for IWXXM (Code Form)
Aerodrome reports	METAR	SA (FM 15 METAR)	LA (FM 205 IWXXM)
	SPECI	SP (FM 16 SPECI)	LP (FM 205 IWXXM)
Aerodrome forecasts	TAF: 12 to 30 hours	FT (FM 51 TAF)	LC (FM 205 IWXXM)
SIGMET information	SIGMET	WS (TEXT)	LS (FM 205 IWXXM)
	SIGMET for TC	WC (TEXT)	LY (FM 205 IWXXM)
	SIGMET for VA	WV (TEXT)	LV (FM 205 IWXXM)
AIRMET information	AIRMET	WA (TEXT)	LW (FM 205 IWXXM)
VA, TC and SWX Advisories	VA Advisory	FV (TEXT)	LU (FM 205 IWXXM)
	TC Advisory	FK (TEXT)	LK (FM 205 IWXXM)
	SWX Advisory	FN (TEXT)	LN (FM 205 IWXXM)
Air-reports	AIREP SPECIAL (ARS)	UA (ICAO AIREP)	-
Administrative	METNO	NO (TEXT)	-

Paula Acethorp has kindly reminded us that METP/5 has discussed the dissemination priority over AFS and had come up with a recommendation:

Recommendation 7/1 — VONA Introduction, VAA and Aerodrome Warning Template Improvements
…
b) request the WMO to develop appropriate headers and priorities for VONA in both TAC and IWXXM format, noting the request by the WG-MOG/IAVW work stream for the highest priority to be assigned;

And in the text of the report: “The work stream also noted that WMO bulletin headers and priorities for VONA to be developed and the highest priority for its dissemination should be assigned, equivalent to that assigned to SIGMET bulletins.”

So T1 shall only be "W" for TAC VONA. For "Warnings" (T1=W), available T2 include B, D, I, J, K, L, M, N, P, Q, X, Y and Z.

Paula further suggested that we may want to consider using T2=M for both TAC and IWXXM VONA, as many Pacific volcanoes are maunga (Māori), mauga (Sāmoa), mo’uga (Tonga), mauna (Hawai’i), or in English – mountains! In that case a recommendation of the TTs for VONA is as followed:

Data type	Abbreviated Name	TT for TAC (Code Form)	TT for IWXXM (Code Form)
Volcano Observatory Notice for Aviation	VONA	WM (TEXT)	LM (FM 205 IWXXM)

Other suggestions for the TTs are most welcomed.

[blchoy]

During the ICAO WG-MIE teleconference on 6 Jun 2023, participants raised the suspicions why METP/5 decided to use T1=W. I would like to leave this to other experts to debate. This posts intends to give some technical information from WMO No.386's perspective on what we could choose for T1 and T2 (updated to include the case when T1="S").

1. Definition of T1 - Table A of Attachment II-5 shows the definitions of data type designator T1, in which:
   'F' indicates a data type of 'Forecasts'
   'S' indicates a data type of 'Surface data'
   'W' indicates a data type of 'Warnings"
   'L' indicates a data type of 'Aviation information in XML'

2. Definition of T2 - Table B of Attachment II-5 shows the definitions of data type designator T2 when T1=A, C, F, N, S, T, U or W while Table B7 of Attachment II-5 shows the definitions of data type designator T2 when T1=L. In particular:
   When T1=F, only T2=Y is available
   When T1=S, T2 can be J and K
   When T1=W, T2 can be B, D, I, J, K, L, M, N, P, Q, X, Y and Z
   When T1=L, T2 can be B, D, E, F, G, H, I, J, L, M, O, Q, R, X and Z

So possible possible options are:

Option 1:
TAC VONA: FY
IWXXM VONA: L[B, D, E, F, G, H, I, J, L, M, O, Q, R, X, Z] (Note: Y is not available)

Option 2:
TAC VONA: S[J, K,]
IWXXM VONA: L[B, D, E, F, G, H, I, J, L, M, O, Q, R, X, Z] (Those T2s that could be the same for both TAC and IWXXM VONA are in bold type)

Option 3:
TAC VONA: W[B, D, I, J, K, L, M, N, P, Q, X, Y, Z]
IWXXM VONA: L[B, D, E, F, G, H, I, J, L, M, O, Q, R, X, Z] (Those T2s that could be the same for both TAC and IWXXM VONA are in bold type)

My previous post indicates a possible choice after discussion with some members of WG-MIE and WG-MOG.

@amilan17 glad if you could confirm if FT2024-1 is the last chance to have the proposed update to WMO No.386 approved before Nov 2024.

[blchoy]

The ICAO APAC ROBEX Handbook also states that the priority indicator of an OPMET message should be set accordingly with regard to its type (irrespective to its Heading):

Glad if experts from other regions can advise their regional practice. Personally I believe this adds more background to OPMET message exchange over AFS, but not necessarily affects how we choose the heading.

[amilan17]

https://github.com/wmo-im/iwxxm/wiki/TT-AvData-Teleconference-2023-Jul-6 notes:
added to FT2024-1 milestone