Blue Skies

What’s up with MET

Getting the Head out of the Clouds“Demisting” the MET

• CAA Met responsibilities (ICAO Met Authority and CAR Part 174)

• Part 174 Organisations

• ICAO compliance

• NZ OPMET (Operational Meteorological Information)

• Met Review (August 2007)

• Changes - 5 November 2008

• Some Surprises and Some Key Facts

• MetFlight-GA

• METAR AUTO

CAA ResponsibilitiesMeteorological Authority (ICAO)

• Ensure ICAO Annex 3 (Meteorological Services for International Air Navigation) provisions are carried out in NZ for all international flight operations. This includes compliance with all Standard and Recommended Practices (SARPs) to the extent possible and practicable (CAA policy). A difference is only filed if there is a sound reason to do so.

• Annex 3 SARPs are based on consultation with 190 member States (countries/territories) plus user organisations such as IATA, IFALPA, IAOPA, IFATCA.

CAA ResponsibilitiesCivil Aviation Rules - Part 174(Aviation Meteorological Service Organisations)

• Conducts entry audits of organisations seeking full or partial Part 174 certification.

• Issues certificates for any period up to 5 years, and subsequently conducts audits as considered appropriate (this may range from spot audits to audits at annual or 2-yearly intervals).

• The granting of a certificate indicates CAA is satisfied the organisation concerned is competent to provide the meteorological services for the service categories specified in the organisation’s certificate.

Part 174 Certificated Organisations

• A Part 174 organisation is required to provide an Exposition which sets out how it will meet the requirements of the Rule. This will include details of personnel, facilities and products that it will provide to support the service categories listed in the organisation’s certificate.

• The particular personnel, facilities and products are not specified by the CAA.

Part 174 Certificated Organisations in NZCertificated Service Categories

• MetService– Forecasts (production and supply of aviation forecasts)

– Information dissemination (collection and dissemination of aviation Met Info)

– Briefing service (supply of Aviation Met info by person and/or system)

– Reporting service (provision and supply of observational information)

– Meteorological watch service (forecast watch and issue of SIGMET)

– Climatology service (supply of historical info for aviation purposes)

• Airways NZ– Information dissemination service (as above)

– Reporting service (as above but restricted to METAR/SPECI)

ICAO ComplianceNZ Operational Meteorological (OPMET) Information

(METAR, SPECI, TAF, SIGMET, VAA)

• TAF, METAR, SPECI - NZAA, NZWN, NZCH only (these are the only NZ international aerodromes specified by ICAO at which ICAO Met services must be provided)

• SIGMET - NZ FIR (NZZC) and Auckland Oceanic FIR NZZO

• Volcanic Ash Advisory - Wellington VAAC area (Eq to 60S, 160E - 140W)

NZ Domestic OPMET & Other Domestic Aviation Weather Information

(METAR, SPECI, TAF, ARFOR, ROFOR etc)

• Certificated Part 174 organisations are free to provide aviation weather information in any format they wish, and to issue the information at times and for validity periods of their choice.

• A Part 174 organisation does not have to provide the aviation weather services for which it is certificated, it is really just “licensed” to do so. However, any services it provides must be compliant with its Exposition.

• Compliance with WMO/ICAO codes is only required if these are used.

However, local differences are permitted and do not require CAA approval or the filing of differences with ICAO.

• Any local differences are determined by the Part 174 organisation in consultation with users, and must be promulgated in AIP NZ.

August 2007Time to take the pulse

• Amendments to ICAO Annex 3 are implemented every 3 years. Latest amendments split between 7 Nov 07 and 5 Nov 08.

• Opportunity taken to review NZ differences (mainly OPMET at NZAA, NZWN & NZCH).

• Also took the opportunity to get some feedback from the industry on impact of applying ICAO compliance to domestic OPMET (METAR, SPECI, TAF).

Action and Reaction

• Discussion paper on CAA website August 2007.

• Presentations made to various groups including AIA.

• Lots of responses (airlines, industry groups, pilots).

• Mixed feedback (some for, against, not sure, not interested).

• But, main conclusion, ICAO compliance at NZAA, NZWN, NZCH generally ok.

So, what will happen on 5 November 2008OPMET (METAR, SPECI, TAF)

• NZAA, NZWN, NZCH

– Full Annex 3 compliance (CAA Decision as the ICAO Met Authority)

– Visibility 10KM or more indicated by “9999”, no cloud above 5,000ft or the minimum sector altitude, whichever is the higher, and use of CAVOK when appropriate.

– 24 Hr TAF for domestic and international operators and Auckland VOLMET. No domestic TAF.

And Domestically

• Domestic OPMET (METAR, SPECI, TAF) No change to current arrangement, except at NZAA, NZWN, NZCH (MetService decision)

– Vis and Cloud continue to be reported without restrictions, and CAVOK not used.

• Review the situation after one year’s experience with full compliance at NZAA, NZWN, NZCH.

• If review indicates no significant issues, consider extending Annex 3 compliance to domestic aerodromes that are not subject to any special operating conditions (eg QN, MC, WF, MF, HK). But industry will be consulted, and any decision will be made by MetService and Airways NZ. CAA is not responsible for domestic OPMET.

Some surprises

• Responses to the discussion paper revealed that MET is not well understood by some pilots.

• Confusion over what is available, where to get it, how to use it and how to correctly interpret it.

• Some pilots only using METAR or BWR for planning.

• Poor understanding and limited use of ARFOR. Also, limited use of radar, satellite pix and surface weather maps.

• Conclusion - some education (and re-education) the order of the day.

• Vector articles, MET pages on the CAA website, AvKiwi (2009), presentations to groups like today.

Some key facts• METAR, SPECI and TAF

– Applicable only to the area within 8 km radius of the aerodrome reference point (extended to 16 km if “Vicinity (VC)” is mentioned). Imagine a cylinder over the aerodrome. METAR, SPECI & TAF provides “at the aerodrome” information.

– Don’t forget “earth curvature” - the horizon is only ~12 km away (at the height vis measurement is made near sea level). Therefore, fog and very low cloud will not be observed beyond about 12-16 km.

– ATS landing and takeoff reports (ATIS/TWR) are the official landing/takeoff reports.

– METAR, SPECI and TAF are largely intended for pre-flight planning.

• Beyond the area covered by a METAR/SPECI/TAF

– Other weather information should be used (eg ARFOR, Wx radar, Satpix, surface wx charts, AWS reports, farmer brown etc).

More key facts

• Where did the 8 and 16 km come from ?

– It’s the international Met standard. Used for SPECI and aerodrome minima criteria.

– Part 91: VFR Vis minima within a control zone is 5 km and in uncontrolled 8km (night).

– AC 61-3: Navigation solo flights are not to be undertaken unless the forecasts are at least 2000 foot ceiling and 16 km visibility.

Keith’s Ezy Wx Guide

When to Use Type of Information

Aviation Wx Product Coverage/Comments

Pre-flight Warnings SIGMET NZ FIR (NZZC). For details of hazardous weather

Initial Big picture NZ weather situation, Surface Wx charts (latest and forecast), radar & satellite pix

To get the big picture and assess an

initial VFR go/no go

Aerodrome TAF, METAR, SPECI, SPAR*, AWS*, BWR* Departure, destination & alternate aerodromes

En-route planning ARFOR (flights up to 10,000ft) Intended route/flight plus any planned alternate routes

In-flight Hazardous weather and aerodrome update

SIGMET, Amended TAF, METAR/SPECI, SPAR*, BWR*

Update of pre-flight information.

Hazardous weather and destination and alternate aerodromes.

* To supplement METAR/SPECI reports, or as a substitute in the absence of METAR/SPECI from the aerodrome(s) concerned.

When to Use Type of Information

Aviation Wx Product Coverage/Comments

Pre-flight Warnings SIGMET NZ FIR (NZZC). For details of hazardous weather

Initial Big picture NZ weather situation, Surface Wx charts (latest and forecast), radar & satellite pix

To get the big picture

Aerodrome TAF, METAR, SPECI, SPAR*, AWS*, BWR* Departure, destination & alternate aerodromes

En-route planning ARFOR (flights up to 10,000ft)

ROFOR (flights abiove 10,000ft)

Intended route/flight plus any planned alternate routes

In-flight Hazardous weather and aerodrome update

SIGMET, Amended TAF, METAR/SPECI, SPAR*, BWR*

Update of pre-flight information.

Hazardous weather and destination and alternate aerodromes.

GA - VFR

GA - IFR

MetFlight-GA

• It’s free to private pilots, training organisations and recreational groups (gliding, ballooning etc) and CAA staff can access it if they wish.

• 4,310 pilots and organisations currently signed up for access.

• Has a ton of information for ground studies and for flight planning (VFR & IFR up to 10,000ft).

• Info available includes:– Wx situation, ARFOR (17 areas), TAF (32 aerodromes), METAR/SPECI (26

aerodromes), SIGMET (NZZC FIR), Wx radar (5 radars), AWS (23 locations), satellite pix (NZ & Tasman sea), surface weather charts (actual and forecast situation), connection to Airways NZ IFIS (for NOTAM and flight plan filing).

• Developed by pilots for pilots and is sponsored by the CAA.

METAR AUTOMETAR from Automatic Weather Stations (AWS)

• This is a MetService initiative. – CAA has given it the nod because it is compliant with MetService’s Part 174

certification and Exposition.

• MetService is doing this because;– ICAO now approve the use of AWS during operational hours (previously only during

non-operational hours). 1,200 aerodromes in the US now have METAR AUTO.– AWS technology has improved greatly over past few years.– Information is available to forecasters every minute, 24/7.– METAR AUTO is provided every 30 mins (ICAO recommendation) 24/7, winter,

summer and during wet or fine weather. No need for SPECI.– AWS can be installed at unattended aerodromes.– The AWS are very reliable, but do have some limitations. However, these are

outweighed by the benefits. This is why METAR AUTO must be used together with other weather information (eg ARFOR, TAF, SIGMET) to get the complete picture for flight planning).

– AWS don’t take annual leave, sick leave, suffer early morning hangovers or go on strike.

Wind, Temperature, Dew Point and QNH

Wind - cup and vane type anemometer or new ultrasonic sensor (mounted 10m above ground)

Temp & dew point - measured electronically mounted in a standard “Stevenson” screen (1.25 m above ground)

QNH - electronic barometer that utilises 3 independent pressure sensors to ensure accuracy and provide redundancy

Cloud Sensors and algorithms

Vaisala laser ceilometers (meteorological industry standard) Uses internationally-recognised US National Weather Service

State of Sky algorithm Precise CLOUD BASE measurements CLOUD LAYERS and COVER determined from cloud ‘hits’ over

sensor during 30 minute period, double-weighted for latest 10 mins

Many comparisons show good correlation

between human and machine observations

Visibility Sensors and algorithms

Vaisala sensors measure MOR Infrared forward scatter technique (ie measures amount of light

scattering by air particles - much research proves this is valid) Air parcel is sampled for clarity/transparency of the air Data averaged over 10 minutes Spot measurements, at representative locations on aerodrome

Meteorological Optical Range (MOR)Meteorological visibility (by day) and meteorological visibility at night are defined as the greatestdistance at which a black object of suitable dimensions (located on the ground) can be seen and recognized whenobserved against the horizon sky during daylight or could be seen and recognized during the night if the generalillumination were raised to the normal daylight level (WMO/ICAO)

Present Weather Sensors and algorithms

Vaisala sensors (combines visibility sensor and a precipitation detector) Proprietary algorithm combines precipitation detection, visibility and

temperature measurements Information is averaged over 15 minutes prior to METAR. Weather

detected during previous 15 minutes (ie back to the last METAR) is coded as “recent” weather using the qualifier “RE”.

Thunderstorms

MetService operates a national Lightning Detection Network

(10 sensors around the country - KT, AK, GS, NP, MS, MK, CH, DN, MO, Whataroa, South Is West Coast )

The sensors identify and locate individual lightning strokes with considerable precision within NZ and beyond

Thunderstorm (TS) is added to METAR AUTO present weather if detected within 8km of aerodrome reference point

Reported as VCTS if between 8 and 16km Recent TS is also reported (RETS)

METAR NZPP 230000Z AUTO 33014G28KT 2200NDV SHRA VCTS FEW016 SCT026 BKN036 10/07 Q0994

Lightning Detection

METAR AUTO Rollout

Location Id Aerodrome Implementation Date

NR

WB

KK

WR

TG

RO

GS

PP

NS

HK

NV

Napier

Woodbourne

Kerikeri

Whangarei

Tauranga

Rotorua

Gisborne

Paraparaumu

Nelson

Hokitika

Invercargill

Implemented

UK

AP

NP

Pukaki

Taupo

New Plymouth

20 November 2008

HN

WK

WU

PM

WS

TU

WF

QN

MF

OU

DN

MO

Hamilton

Whakatane

Wanganui

Palmerston North

Westport

Timaru

Wanaka

Queenstown

Milford Sound

Oamaru

Dunedin

Manapouri

1 July 2009

MS

KT

CI

Masterton

Kaitaia

Chatham Is

1 December 2009

How do you recognise an Aviation AWS (METAR AUTO)

Aviation AWS METAR AUTO

NZPP:METAR 090300Z AUTO 19014KT 160V230 51KMNDV // BKN033/// 07/01 Q1013

AWS METAR (some have cloud and vis sensors but are older type AWS)

NZDNA: (AUTOMATIC WEATHER STATION REPORT)METAR 090300Z AUTO 25008KT 55KMNDV // SCT031/// BKN055/// 05/02 Q1018

NZGCE: (AUTOMATIC WEATHER STATION REPORT)METAR 090300Z AUTO 00000KT // ///////// 05/00

Airways METAR

NZPM:METAR 090300Z 11003KT 060V170 30KM VCSH FEW020 SCT032 BKN045 06/02 Q1010 RMK SH TO NTH

That’s all folks