International Civil Aviation Organization
VAAC Best Practices Seminar
Summary of Discussions
ICAO Headquarters, Montreal
13 and 14 February 2012
Background…
• A number of ICAO IAVWOPSG and IVATF conclusions between
2004 and 2011 have addressed aspects of harmonization and
best practices.
• IAVWOPSG Conclusion 6/8 (19 to 23 September 2011):
Workshop to develop VAAC best practices
That Australia, in conjunction with WMO, be invited to facilitate a
workshop for all VAACs in 2012 or 2013 to share, develop and
document VAAC best practices, in order to support harmonization
of the VAACs’ operating procedures and to mitigate inconsistency
for operators.
Note.— The workshop should consider all aspects of VAAC operations,
including but not limited to, lead VAAC and coordination, emission source
parameters, satellite analysis, trajectory and dispersion modelling and
output. The outcome of the workshop should be presented as soon as
possible and reported to IAVWOPSG/7.
VAAC Best Practices Seminar – Montreal – 13-14 February 2012
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Volcanic Ash Challenge Team (20/9/11):
Considering the needs for improved continuity
between adjacent VAAC areas of responsibility,
clarification of user requirements and assistance to
VAACs in development and deployment of existing
and new products, the VACT agreed as follows:
That the industry (IATA, ICCAIA, IFALPA) will work with
the VAACs, through the IAVWOPSG, to develop a
standardized product by June 2012 that meets the
user requirements so as to allow for safe and efficient
flight operations.
Action: IATA, ICCAIA, IFALPA
VAAC Best Practices Seminar – Montreal – 13-14 February 2012
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Opening discussions...
• Presentations from ICAO and IATA on user
requirements and expectations.
• In addition to harmonization and other
requirements, the meeting also discussed and
noted the importance of transparent and
sustainable cost-recovery by VAACs. This may
be essential to implement IAVW
improvements.
Best practice questionnaire
• Each VAAC answered a
wide-ranging questionnaire,
with results kindly collated
and analysed by New
Zealand (see next slides).
• The issues identified were
discussed, and break-out
groups discussed themes in
more detail.
Opportunities identified from questionnaire (1)
The questionnaire responses indicate a high standard of professional
practice, and broad consistency in approach, across all the VAACs. There
are a number of opportunities to further our collective capability…
• Collaboration on the application of observing techniques
– Satellite applications are a rapidly changing area and some VAACs may find it
a challenge to stay at the cutting edge
– Sharing experiences with alternative methods – e.g., social media
• Lead VAAC concept may benefit from a common set of “rules of engagement”, so
that VAACs benefits from cooperation without feeling a loss control over their AoR
• Training of staff in nominated backup centres, and routine testing of backup
capabilities, appear to be areas of weakness for most VAACs.
• A more formalised approach to data exchange between neighbouring VAACs during
events may simplify coordination efforts in complex situations
Opportunities (2)
•
Sophistication of dispersion modelling at some VAACs is advancing rapidly – this
may lead to an increasing gap in capability between VAACs
– Is the more advanced capability leading to better forecasts or products for end
users?
– If so, can we ensure that all VAACs are able to deliver to a common standard in
terms of modelling?
•
Initialising an ATDM with an analysis to combine obs and modelling – a potential
goal for “best practice” may be to enable this across all VAACs
•
There is limited capability to deal with uncertainty in ash cloud forecasts, despite
this being an area of interest for IATA. If we are ultimately to provide probabilistic
information, how can this be done objectively?
•
Should there be common standards for VAAC performance – e.g., minimum
response times, verification of outputs? Cf IATA requests.
Opportunities (3)
• Minimum requirements for observational evidence before issuing or
altering a VAA?
• Should there be a common approach to the “shelf life” of an existing VAA
in the absence of supporting observational evidence?
• Should there be a common policy on complexity of ash layer descriptions
in VAA?
• All of the VAACs except one operate with staff who have other operational
duties. Recent challenging events (Iceland events, Cordon Caulle) have
seriously stretched VAAC resources… perhaps it’s time for some of us to
rethink our operational models?
Lots of issues….
• Focused on most
important and
achievable themes
– low hanging fruit.
Low hanging fruit
Key themes
1. “Visible Ash” and how an area of ash is
analysed (or forecast) in Volcanic Ash
Advisories.
2. Data exchange, the role of the ‘Lead VAAC’,
collaborative decision-making, and forecast
validation
3. Articulating forecast confidence/uncertainty
 Increased mutual understanding
 Better outcomes
1. “Visible ash”, analysis, consistency etc
Detailed discussion shows that VAACs will do slightly
different things based on their interpretation of the
evidence available and Annex 3 / Handbook
provisions, eg:
• Without satellite evidence but with other
observations, will a VAAC attempt a full dispersion
forecast or simply give winds?
• Advisory cessation
• Following initial issue, advisory validity times
following standard cycle (0Z, 6Z, 12Z, 18Z), or
matched to SIGMETs, or staggered for workload
“Visible ash”, analysis, consistency etc
What “Visible Ash” is can be taken back to the
question posed by the AIR group in IVATF/2
(paraphrased) ‘what are the practices that
have so far kept us safe?’
i.e. Given the evidence and modelling available
in a situation, can we agree and document
how VAACs will consistently, objectively
produce ‘ash/no ash’ Volcanic Ash
Advisories?
“Visible ash” defined?
“Visible ash” – volcanic ash that, in the professional
judgement of the VAAC, is likely (or observed) to be
detectable by human eye or remote sensing (using
multi-spectral techniques) in good visibility
conditions. This judgement will be based on
agreement on best-practice, and also by further
information from the OEMs on susceptibility of
aircraft to ash cloud.
Ash that would not be observable in good conditions is
not subject to the warning system and, for the
purposes of all references to volcanic ash in SARPs
etc, is ignored until agreed otherwise.
Resolving differences in practice
•
•
A paper will be prepared for IVATF/4
outlining how VAACs will converge
further to common practice in matters
relating to the handling of observations
and modelling for marginal situations.
Target for endorsement: IAVWOPSG/7.
Confidence Levels
• IATA proposal for Confidence Levels.
– Confidence (High, Medium, Low)
•
•
•
•
•
•
VAA level of confidence
Source term
Plume height
Lateral observed extent
Model output
Additional observation information
– Best Practices sub-team evaluated IATA proposal
• Decided to apply confidence to T+0 polygon only at this
time.
Project title (Insert, Header & Footer)
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Confidence (2)
• 3 confidence levels – High, Medium, Low
• Walk before run
– Confidence levels applied to T=0 ash cloud
position (polygon) of the VAA
– Future goal: Confidence levels applied to forecast
positions (T+6 etc)
• Confidence levels do not apply to the VAAC
capability, rather it is commentary on the
current meteorological and volcanological
environments
Project title (Insert, Header & Footer)
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Confidence (3)
Confidence Level
Criteria for T=0
High (meets all 3)
•More than 2/3 of polygon contains identified/discernible ash
cloud , and
•Ash cloud edges( with respect to polygon) mostly (2/3)
discernable, and
•plume height and/or ash cloud top reported or measured
(objectively) (e.g., Radar, Lidar, satellite, etc)
Medium (meets 2)
•Between 1/3 and 2/3 of polygon contains
identifiable/discernible ash cloud.
•Between one third and two thirds of ash cloud’s edges
discernable
•Plume height and/or ash cloud top estimated from recent data
(<12 hours)
Low
•Less than1/3 of polygon contains identiable/discernable ash
cloud.
• Ash cloud edges uncertain.
•Plume height and/or ash cloud top unconfirmed
Project title (Insert, Header & Footer)
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Confidence (4)
• How to get there?
– Present to IATA
– Present to IVATF
– Hand off to IAVWOPSG
– Possible solutions
• Include in Remarks
section of text VAA and
VAG
Project title (Insert, Header & Footer)
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Confidence (5) – future development
• Initial thoughts on defining confidence levels
for forecast polygons. Look at:
– Confidence level of the T+0 polygon.
– Ability to define ESP (especially plume height).
– Stable synoptic weather pattern (compared to a
complex pattern with fronts, strong wind shearing
with altitude) and the handling by NWP models.
– New polygons consistent with previous forecast’s
polygons. (e.g., old T+12 forecast = new T+6
forecast)
– Stratospheric vs Tropospheric eruption?
Project title (Insert, Header & Footer)
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3. Coordination across VAAC boundaries
• To ensure consistency between VAACs (borders, layers, etc.)
• Change ‘’LEAD’’ TO ‘’PRIMARY’’
• Definition: PRIMARY VAAC is defined as the VAAC with responsibility
for coordinating the production of advisories for volcanic eruptions
originating within its designated area of responsibility
• When an ash cloud ash approaches (550 km) another VAAC’S area of
responsibility, the Primary VAAC will coordinate with the
neighbouring VAAC to produce a seamless product covering the 2
areas of responsibility. ( Depending on circumstances, the 2 VAACs
may issue their own VA but the PRIMARY VAAC will ensure
consistency at the border (this is already permitted in Handbook)
• If the ash cloud moves into the area of responsibility of a third VAAC,
the second VAAC is responsible for initiation coordination with it.
VAAC Best Practices Seminar – Montreal – 13-14 February 2012
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Coordination across VAAC boundaries (2)
• GENERAL PRINCIPLE (closed door coordination between VAACs): If
differences arise between the originating VAAC and the other VAAC on
the extent of the ash cloud, the latter will have final say over its area of
responsibility.
• Where felt necessary, the coordination procedures may be established
through written agreements between VAACs.
• Proposal: Paper to be submitted to IAVTF4 to modify Handbook of
IAVW - develop ideas on coordination, primary and other VAAC , make
hand off a separate section
• This will be done by members of IAVWOPSG (specific proposals for
modifications to Handbook)
• Look and feel of VAG: is it possible to use the same map projection?
• COLLABORATIVE TOOL WOULD - WILL HELP GREATLY
VAAC Best Practices Seminar – Montreal – 13-14 February 2012
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Resourcing
• From the survey it seems that most of the VAACs are
funded in the margins of their host organisations and
that until recently little economic analysis has been
done by those organisations to optimise their
investment in this increasing important field.
• It is suggested that such an exercise would show
scope for further investment in better staffing
regimes and better access to technology and
communications. This work could be achieved
through a single consulting project on behalf all
VAAC host organisations.
Resourcing (2)
• This is an issue that goes wider than the
VAACs (eg WAFS)
• The seminar requests guidance (to
IAVWOPSG?) from the ICAO Secretariat on
how to progress these issues.
Follow-up
• This has been a very useful meeting. In
practice, and noting budgetary and time
constraints, it would be difficult to have a
quick follow-up.
• Follow-up through IVATF & IAVWOPSG where
possible
• WMO Volcanic Ash Workshop in March 2013
for science-related issues.