Meteorology
Short Description
general meteorology...
Description
General Part
12-MAY-2011 I
Meteorology
T E M
Table of Contents
General Information
1
2
Meteorological Documentation Support
Flight Documentation
and
1.1
General
10
1.2
Aviation Weather Services
10
1.2.1
General
10
1.2.2
Data
10
1.3
Observation and Reports
10
1.4
Meteorological Offices
10
1.5
Weather Assistance by ATC
10
1.6
Ground Weather Radar
20
1.7
Windshear and Turbulence Warning System
20
2.1
General
20
2.2
Standard Flight Documentation
20
2.3
Reduced Flight Documentation
30
2.4
Contents of Flight Documentation
30
2.4.1
Significant Weather Chart (SIGWX)
30
2.4.2
Upper Wind and Temperature Chart
80
2.4.3
ICAO Codes - TAF & METAR
90
2.4.3. 2.4 .3.1 1 2.4.3.2
Operat Ope ration ional al Me Meteo teorol rologi ogical cal Inf Inform ormati ation on (OP (OPMET MET)) Data Bank Interrogation Designator Delayed/Corrected OPMET
90
2.4.3.3
Aerodrome Forecast - TAF
90
2.4.3.4
Aerodrome Report - METAR / SPECI
110
2.4.3.5
Aerodrome Trend Forecasts
120
2.4.3.6
Additional Information to ICAO Codes
120
2.5
SIGMET / AIRMET
130
2.5.1
SIGMET General
130
2.5.2
AIRMET General
130
2.5.3
SIGMET / AIRMET - ICAO Code Content
130
2.5.4
Tropical Cyclone SIGMET - TC
130
2.5.5
Volcanic Ash SIGMET - VA
130
2.5.6
SIGMET / AIRMET U.S. System
140
2.6
Aerodrome Warnings
140
2.6.1
Aerodrome Warnings - AD Warning
140
2.6.2
Wind Shear Warnings - WS WRNG
140
90
1 1 0 2
o d i L ©
Sheet 471323
*471323* LSY Standard (jetww)
T E M
General Part
12-MAY-2011 II
3
4
5
6
In-Flight Information
Aircraft Observations and Reports
Volcanic Ashreports
Activity
Potential Flight Hazards
/
Meteorology
3.1
General
14 0
3.2
Air to Ground Datalink
14 0
3.3
ATIS / VOLMET
14 0
3.3.1
ATIS (A (Automated Te Terminal In Information Se Service)
14 0
3.3. 3. 3.2 2
VOLM VO LMET ET (Me (Mete teor orol olog ogic ical al Inf Infor orma mati tion on fo forr Airc Aircra raft ft in-Flight)
150
4.1
Reporting Of Aircraft Observations During Flight
15 0
4.2
Routine Aircraft Observations
15 0
4.3
Special an and Ot Other No Non-Routine Ai Aircraft Observations
160
5.1
General
16 0
5.2
ASHTAM
17 0
6.1
General
17 0
6.2
Turbulence
17 0
6.2.1
Turbulence Grade Classification
17 0
6.2.2
Clear Air Turbulence (CAT) Encounter
18 0
6.2.2.1
General
18 0
6.2.2.2
Clear Air Turbulence Phenomenon
18 0
6.2.2.3
Forecast Presentation
18 0
6.2.2.4
Convective Induces Turbulences
18 0
6.2.2.5
Topographically induced Turbulence
18 0
6.2.2.6
Wake Turbulence
18 0
6.3
Precipitation, Icing
18 0
6.3.1
General
18 0
6.3.2
Categories of Precipitation
18 0
6.3.3
Classification of Precipitation Intensity
18 0
6.3.4
Airframe Categories of Icing
19 0
6.4
Special Winter Phenomena
19 0
6.4.1
Thunderstorms, CB / TCU
19 0
6.4.2
Downdraft and Microburst (MB)
19 0
6.4.2.1
Microburst on final
20 0
6.4.2.2
Microburst after Take-Off
20 0
6.4.3
Mountain Waves (MTW)
21 0
6.4.4
Wind Shears
21 0
6.4.5
Inversion
21 0
1 1 0 2
o d i L ©
Sheet 471323
LSY Standard (jetww)
T E M
General Part
12-MAY-2011 II
3
4
5
6
In-Flight Information
Aircraft Observations and Reports
Volcanic Ashreports
Activity
Potential Flight Hazards
/
Meteorology
3.1
General
14 0
3.2
Air to Ground Datalink
14 0
3.3
ATIS / VOLMET
14 0
3.3.1
ATIS (A (Automated Te Terminal In Information Se Service)
14 0
3.3. 3. 3.2 2
VOLM VO LMET ET (Me (Mete teor orol olog ogic ical al Inf Infor orma mati tion on fo forr Airc Aircra raft ft in-Flight)
150
4.1
Reporting Of Aircraft Observations During Flight
15 0
4.2
Routine Aircraft Observations
15 0
4.3
Special an and Ot Other No Non-Routine Ai Aircraft Observations
160
5.1
General
16 0
5.2
ASHTAM
17 0
6.1
General
17 0
6.2
Turbulence
17 0
6.2.1
Turbulence Grade Classification
17 0
6.2.2
Clear Air Turbulence (CAT) Encounter
18 0
6.2.2.1
General
18 0
6.2.2.2
Clear Air Turbulence Phenomenon
18 0
6.2.2.3
Forecast Presentation
18 0
6.2.2.4
Convective Induces Turbulences
18 0
6.2.2.5
Topographically induced Turbulence
18 0
6.2.2.6
Wake Turbulence
18 0
6.3
Precipitation, Icing
18 0
6.3.1
General
18 0
6.3.2
Categories of Precipitation
18 0
6.3.3
Classification of Precipitation Intensity
18 0
6.3.4
Airframe Categories of Icing
19 0
6.4
Special Winter Phenomena
19 0
6.4.1
Thunderstorms, CB / TCU
19 0
6.4.2
Downdraft and Microburst (MB)
19 0
6.4.2.1
Microburst on final
20 0
6.4.2.2
Microburst after Take-Off
20 0
6.4.3
Mountain Waves (MTW)
21 0
6.4.4
Wind Shears
21 0
6.4.5
Inversion
21 0
1 1 0 2
o d i L ©
Sheet 471323
LSY Standard (jetww)
General Part
22-SEP-2011 III
Meteorology 7
8
Winter Operation
Decoding Meteorological Data Meteorological
of
7.1
Fluids and Procedures
210
7.1.1
De-/Anti-Icing Instructions
210
7.1.2
De-Icing and Anti-Icing Procedures
210
7.1.2.1
De-Icing / Anti-Icing Checks
220
7.1.2.2
Communication Procedure
230
7.1.3
Types of Fluids
240
7.1.3.1
General
240
7.1.3.2
Type I Fluids
250
7.1.3.3
Type II Fluids
250
7.2
Hold-Over-Time (HOT) Policy
250
7.2.1
General
250
7.2.1.1
Lowest Op Operational Us Use Te Temperature (L (LOUT):
260
7.2.2
One-Step- / Two-Step Guidelines
260
7.2.2.1
Type I Fluid
260
7.2.2.2
Type II, III and IV Fluids
260
7.2.3
HOT Active Frost Type I, II, III, and IV Fluids
270
7.2.4
Various Weather Conditions Type I Fluid
280
7.2.5
Various Weather Conditions Type II Fluid
290
7.2.6
Various Weather Conditions Type III fluid
300
7.2.7
Various Weather Conditions Type IV fluid
310
7.3
Adverse Runway Condition
320
7.3.1
Dissemination of RWY State Information
320
7.3.2
SNOWTAM
320
7.3.2.1
Issue/Validity of SNOWTAMs
320
7.3.3
METAR Runway Report
320
7.3.4
Issue/Validity of RWY Reports.
320
7.3.4.1
Assessment of Deposit
320
7.3.4.2
Measuring Devices
330
7.3. 7. 3.4. 4.3 3 7.3.4.4
Rela Re lati tion onsh ship ip Betw Betwee een n Frict Frictio ion n Coeff Coeffic icie ient nt (FC) (FC) and Braking Action (BA) Differences from ICAO Standard
340
8.1
TAF & METAR Decoding (ICAO)
340
8.1.1
Runway Report Decoding
370
8.2
Military (N (NATO) Co Color Co Coded We Weather Co Conditions
380
8.3 8.4
SIGMET / AIRMET - (OPMET Data Bank Designator) ASHTAM Decoding
390
8.5
SNOWTAM Decoding
400
T E M
340
390
1 1 0 2
o d i L ©
Sheet 515541
*515541* LSY Standard (jetww)
LSY Standard (jetww)
General Part
14-OCT-2010 10
Meteorology
T E M
1 Meteorological Documentation and Support 1.1 General This chapter describes ground and high altitude atmospheric conditions and weather phenomena. It covers mainly the decoding of weather reports (To clarify the content of the text, examples are added).
1.2 Aviation Weather Services 1.2.1 General c
During aerodrome hours, the meteorological office is providing all necessary information for flight operations. At some aerodromes airline operators and crew members can retrieve required documents using an remote briefing location. Weather briefings may be provided via video conferencing facilities or telephone to flight crew members prior to departure. Exceptions are stated in the “Regional Supplementary Information” (RSIs) and “Country Rules and Regulations” (CRARs) of the Lido/RouteManual. 1.2.2 Data
Aviation weather services consist of data acquisition, forecast production, and information dissemination; the latter is encompassing pre and in-flight requirements for cockpit crew and dispatch personnel.
1.3 Observation and Reports Meteorological stations are established at aerodromes or other significant points for air-navigation and are manned by humans or electronic measuring equipment. The observation forms the basis for the preparation of forecast and actual weather reports. These reports are coded in accordance with the International Civil Aviation Organization (ICAO) or the World Meteorological Organization (WMO) and distributed worldwide.
1.4 Meteorological Offices Meteorological offices are providing briefing, consulting, and flight documentation to flight crew or other flight operations personnel. They forward relevant information to air traffic control centers to communicate reports of hazardous weather to flights.
1.5 Weather Assistance by ATC Meteorological information of interest to pilots in-flight should be supplied by Air Traffic Service (ATS) and normally consist of the following: • non-routine and special reports • SIGMET and AIRMET Air Traffic Control (ATC) will issue information on significant weather and assist pilots in avoiding weather areas during all phases of flight. For safety reasons, an IFR flight must normally not deviate for meteorological reasons from an assigned course or altitude without a proper ATC clearance. ⇒
Navigation General Information
2.4 Weather Deviation Procedure
Pilot’s requests to ATS for transmission of weather reports may be done for aerodromes with no Automatic Terminal Information Service (ATIS/D-ATIS) or not covered by meteorological broadcast (VHF VOLMET/D VOLMET). For departing aircraft: ATC transmits weather information regarding significant changes (surface wind direction/speed; VIS/RVR; Thunderstorms/Cumulonimbus; moderate/severe turbulence/icing; severe squall Sheet 384886
*384886* LSY Standard (jetww)
0 1 0 2
o d i L ©
T E M
General Part
14-OCT-2010 20
Meteorology
line/mountain waves; freezing precipitation; sand/dust storm; blowing snow; tornado; waterspout) except when it is known that aircraft has already received the information. (ATIS).
1.6 Ground Weather Radar Typically presents a display of precipitation within 150NM of the facility site; storms of considerable heights and intensity can be seen at greater ranges.
1.7 Windshear and Turbulence Warning System The Windshear and Turbulence Warning System (WTWS) will provide pilots in real-time windshear and turbulence alerts from 3NM on final approach to 3NM on departure. These warnings will be verbally relayed by ATC from information on alphanumeric alert display (AAD). Example of WTWS:
07LA WSA 15K+ 3MF means: RWY 07L Arrival Windshear Alert 15KT gain at 3 miles final or 07RD MBA 35K- 2MD means: RWY 07R Departure Microburst Alert 35KT loss at 2 miles. General warnings and TREND forecast will be broadcasted on ATIS/D-ATIS. Example of ATIS Arrival Information:
0920 07L 120/15G22 7000 RA BRK18 QNH 1012 Warning windshear on final.
2 Flight Documentation 2.1 General Documentation is required for each flight. The documentation must cover the flight in respect of time, altitude and geographical extent including the route between destination and destination alternate. Presentation may vary according to regional agreements and standards. Flight documentation must be supplied (or updated in case of delay) as close to departure as practicable.
2.2 Standard Flight Documentation Containing: • Significant Weather Chart (SIGWX) -
including wind forces (jet streams) and tropopause heights.
• Upper winds and temperature charts -
Aerodrome forecasts, actual and special report (For example: RWY report)
-
for aerodrome of departure, take-off alternate if required, destination and destination alternates
-
for flights of more than 2 HRs the forecast must cover en-route alternates.
• Information of specified en-route weather phenomena (SIGMET) -
Concerning volcanic ash clouds and tropical cyclones must be based on advisory information provided by Volcanic Ash Advisory Centers (VAACs) and Tropical Cyclone Advisory Centers (TCACs)
0 1 0 2
o d i L ©
Sheet 384886
LSY Standard (jetww)
General Part
14-OCT-2010
Meteorology •
30
T E M
Low Level en-route weather (AIRMET) -
Information (for example: windshears, icing, inversion) for short flights below FL100, FL150 in mountainous areas or as specified by the local meteorological office.
2.3 Reduced Flight Documentation c
In general, a flight shall not be commenced until the provision of meteorological information satisfies the pilot-in-command. For deviation in terms of content and validity of meteorological information for the intended type of operation refer to the respective Airline Operation Manual.
2.4 Contents of Flight Documentation 2.4.1 Significant Weather Chart (SIGWX) Charts available from World Area Forecast Center (WAFC) London: • Low Level (SWL): SFC-10000ft (15000ft in mountainous areas) with fronts (not provided by all states and not disseminated internationally). Note: Upper limits of SWL provided by local country MET services can differ • Medium Level (SWM): FL100 to FL250 (only available for dedicated areas, defined in ICAO Annex 3) • High Level (SWH): FL250 to FL630 Medium/High Charts Include: • Tropical Cyclone when mean surface wind speed ≥ 34KT • Severe squall lines • Moderate or severe turbulence (in cloud or clear air) • Moderate or severe icing • Widespread sand/duststorm • Cumulonimbus clouds associated with thunderstorm and with items above • Flight level of tropopause • Jet streams • Information on the location of volcanic eruption • Information on the location of an accidental release of radioactive materials into the atmosphere.
0 1 0 2
o d i L ©
Sheet 384887
*384887* LSY Standard (jetww)
T E M
General Part
14-OCT-2010 40
Meteorology
High level significant weather chart (SWH) example
Medium level significant weather chart (SWM) example 0 1 0 2
o d i L ©
Sheet 384887
LSY Standard (jetww)
General Part
14-OCT-2010
Meteorology
50
T E M
Low level significant weather chart (SWL) example 0 1 0 2
o d i L ©
Sheet 384888
*384888* LSY Standard (jetww)
T E M
General Part
14-OCT-2010 60
Meteorology
Legend for significant weather charts (SIGWX) General
Significant Weather Charts (SIGWXs) are issued by the World Area Forecast Centers (WAFC) in London and/or Washington. • Fixed Time/Date Forecast Chart. Valid times are: 06, 12, 18 and 00 UTC. Head
• Units used: knots; altitude in FL; • CB implies TS, GR, moderate or severe turbulence and ice. • Check SIGMETs, advisories, ASHTAM and NOTAM for volcanic ash
Tropopause heights
Indication numbers are in squares followed by moderate or severe turbulence symbols and FL.
CAT Area
The position/axis of a jet stream is shown as a heavy solid line with wind speed marks and change bars. The jet stream axis begins/ends at the point where a wind speed of 80KT is forecast. The change bar denotes a change of speed of 20KT. The FL of the 80KT isotach above and below the maximum wind speed level is shown. (Only speed of 120KT or more will contain vertical depth information.)
Cloud amount, type and height
Sky cover is shown as FEW (50 1.0g. Occupants forced violently against seatbelts. Loose objects tossed about. Reported as “Turbulence severe”.
Sheet 471328
*471328* LSY Standard (jetww)
1 1 0 2
o d i L ©
T E M
General Part
12-MAY-2011 180
Meteorology
6.2.2 Clear Air Turbulence (CAT) Encounter 6.2.2.1 General
World Area Forecast Centers (WAFC) London and Washington are providing the most accurate information to users: Significant Weather Charts (SIGWX) for high and medium levels, upper wind and temperature charts are provided. 6.2.2.2 Clear Air Turbulence Phenomenon
Clear Air Turbulence (CAT) layers are found along front lines and their jet streams. These areas of vertical exchange of air mass are the most dynamic and significant where two tropopauses overlap each other. When turbulence becomes excessive, an altitude change is more efficient than a track change. 6.2.2.3 Forecast Presentation
The forecast of Clear Air Turbulence (CAT) areas (dashed lines) on SIGWX provide no information of light turbulence. It is a fact that temporary change of a certain level has the greatest influence on the development of CAT. 6.2.2.4 Convective Induces Turbulences
Due to heat radiation from different ground states, e.g. forests, lakes, rocks, RWYs etc. Climb out and approach phase can be uncomfortable. 6.2.2.5 Topographically induced Turbulence
In strong wind conditions behind hills, buildings, etc. These conditions may also cause wind shear. 6.2.2.6 Wake Turbulence
Behind aircraft consists of two counter-rotating cylindrical vortices. The pressure differential between the upper and the lower side of the wing triggers the roll up of the airflow aft of the wing, resulting in swirling air masses trailing downstream of the wing tips. Pilots should avoid a region within less than 200ft of the vortex core. When flying on track systems in oceanic or remote areas offset procedures (i.e. SLOP) may be applied.
6.3 Precipitation, Icing 6.3.1 General
Precipitation can severely reduce Visibility (VIS) and can give a false optical illusion during landing phase. A flooded, contaminated RWY may deteriorate the braking coefficient towards zero (aquaplaning). 6.3.2 Categories of Precipitation
• Vapor Consists of very small drops of water which form haze, mist, and fog. This form of precipitation reduces the VIS drastically. • Liquid Forms of precipitation are drizzle and rain. • Frozen Forms are snow, snow grains, snow pellets, ice pellets, and hail. 6.3.3 Classification of Precipitation Intensity
With regard to precipitation, detection thresholds expressed in Millimeter per Hour (mm/h) are given for some sensors. The World Meteorological Organization (WMO) reporting thresholds for light, moderate and heavy precipitation are shown in Table. 1 1 0 2
o d i L ©
Sheet 471328
LSY Standard (jetww)
General Part
12-MAY-2011 190
Meteorology Intensity
Drizzle
Rain
Snow
Light
< 0.1 mm/h
< 2.5 mm/h
< 1.0 mm/h
Moderate
0.1 and < 0.5 mm/h
2.5 and < 10 mm/h
1.0 and < 5 mm/h
Heavy
0.5 mm/h
10 mm/h
5 mm/h
T E M
6.3.4 Airframe Categories of Icing
• Rime Thin milky film of frozen vapor. • Frost Rough, milky and opaque ice formed by the instantaneous freezing of small water droplets or snow flurries. • Clear ice Glossy, clear, or translucent ice formed by slow freezing of water droplets.
6.4 Special Winter Phenomena 6.4.1 Thunderstorms, CB / TCU
Turbulence, hail, snow, lightning, sustained up- and downdrafts, icing conditions - are all present in thunderstorms. Up- and downdrafts extend far beyond the visible storm cloud. Severe turbulence can be expected up to some distance from large thunderstorms. 6.4.2 Downdraft and Microburst (MB)
A Downdraft is a relative small scale downward current of air; often observed on the lee side of large objects restricting the smooth flow of the air or in precipitation areas in or near Cumuliform Clouds. Microburst are small-scale intense cold air downdrafts out of cumulus clouds or thunderstorm cells which, on reaching the surface, spread outward in all directions from the downdraft center. This causes the presence of vertical and horizontal wind shear, especially at low altitude within some 1000ft of the ground. Microburst either occur as wet microburst carrying precipitation to the ground or as dry microburst descending from cumulonimbi or towering cumuli with a high cloud base (around 10000ft), typically in desert regions. Size:
The strong downdraft is typically less than 1NM in diameter; the horizontal outflow can extend to approx. 4NM in diameter. Intensity:
The downdrafts can be as strong as 8000ft/MIN. Horizontal winds speeds near the surface can reach up to 100KT. Visual sign:
They may be embedded in heavy rain associated with convective clouds or little or no precipitation. The main flight hazards of a microburst are: • severe low level wind shear, • the strong downdraft, • severe turbulence at the gust front. 1 1 0 2
o d i L ©
Sheet 471329
*471329* LSY Standard (jetww)
T E M
General Part
12-MAY-2011 200
Meteorology
Other hazards found below thunderstorms may join the already critical situation, like heavy rain, hail, aquaplaning, lightning, and tornadoes. Wind shear may be horizontal, vertical wind shear, and up and downdraft shears. A flight through a microburst lasts only for seconds. The history of an aircraft encountering a microburst strongly depends on its path through the microburst and the phase of flight. 6.4.2.1 Microburst on final
A pilot penetrating a microburst during final approach will first experience a strong headwind, the aircraft first balloons above the glide slope due to air speed rise shear. Entering the downdraft there is air speed loss shear, downdraft shear, and the vertical displacement by the downdraft, which altogether leads to a dramatic loss of height. Finally a strong tailwind signifies another air speed drop shear. Additionally the aircraft may encounter turbulence at the gust front. 6.4.2.2 Microburst after Take-Off
An aircraft taking off in a microburst will first encounter a stronger headwind and thus a speed increase (1). After take-off, upon entering the tailwind area speed drops and the nose has to be lowered (2). In case of further downdraft activity the airplane may continue to sink and ground impact becomes imminent (3). Detection: Due to their small size, short lifespan and the fact that they often occur over areas without surface precipitation, microburst are not easily detectable using conventional weather radar or wind shear alert system. 1 1 0 2
o d i L ©
Look out for signs of convective weather, like CU, TCu, showers, and virga. Read (and issue) pilot reports, but do not rely on them too much, since the microburst changes by the minute. The bending of trees, dust, and sand in the air may be the only up to date information on the wind field around the aerodrome. Sheet 471329
LSY Standard (jetww)
General Part
22-SEP-2011
Meteorology
210
T E M
6.4.3 Mountain Waves (MTW)
Mountain waves occur when air is being blown over a mountain range. As the air hits the upwind side of the range, it starts to climb, thus creating a smooth updraft which turns into a turbulent downdraft as the air passes the crest of the ridge. From this point, for many miles downwind, there will be a series of down- and updrafts accompanied by moderate to severe turbulence. 6.4.4 Wind Shears
Wind shear conditions are normally associated with the following phenomena: • thunderstorms, microburst, tornado, and gusts. • frontal surfaces • mountain waves • strong wind coupled with local topography • see breeze fronts • low-level temperature inversions 6.4.5 Inversion
An increase of temperature with height - a reversal of the normal decrease with height in the troposphere. In inversions windshear may be encountered.
7 Winter Operation 7.1 Fluids and Procedures 7.1.1 De-/Anti-Icing Instructions
Generally, de-/anti-icing instructions, information and procedures used by the flight crews are published in the respective manual. For ground personnel dealing with aircraft de-/anti-icing, a separate "De-/ Anti-icing Manual" (DAM) has been established. Before aircraft treatment and de-/anti-icing fluid application, the pilot must check that the type of aircraft is known by the ground personnel. During off-gate de-icing, two-way communication between pilot and de-/anti-icing operator/supervisor must be established prior to de-/anti-icing treatment. This shall be accomplished either by intercom or by VHF radio. All de-/anti-icing actions must be entered in the aircraft log. The appropriate information will be communicated by the ground personnel and the respective de-/anti-icing code (fluid type, mixture, and the time the final de-/anti-icing step commenced, e.g. “Type II, 75/25, 1155”), shall be entered by the flight crew into the Technical Log on the “Complaint” side of the log slip. 7.1.2 De-Icing and Anti-Icing Procedures
De-icing is a procedure by which frost, slush, snow, or ice is removed from the aircraft in order to provide clean surfaces. Anti-icing is a precautionary procedure which provides protection against the formation of frost or ice and accumulation of snow or slush on treated surfaces of the aircraft for a limited period of time (hold-over-time). De/anti-icing is a combination of de-icing and anti-icing and may be performed in one or two steps. Normally, if not otherwise requested by the pilot, the entire aircraft will be completely de-iced and cleaned of any frost, slush, snow, and ice. For exceptions/operating limits and for local frost prevention or removal, refer to OM-B/AOM. The spray operator is aware that the forward fuselage (nose to forward passenger/service door section) requires special attention in order to avoid soiled cockpit windshields. This area is normally cleaned by hot water only.
1 1 0 2
o d i L ©
Sheet 515542
*515542* LSY Standard (jetww)
General Part
T E M
22-SEP-2011 220
Meteorology
If, however, the cockpit windshields and/or the nose of the aircraft should be soiled by de-/anti-icing fluid, the area must be cleaned by rinsing clear hot water and in addition, the windshields shall be cleaned with a soft cloth prior to departure. Windshield wipers, however, shall not be used for this purpose. a
Anti-icing Fluid
De-icing Fluid
a
• Mixture of water and Type I fluid (Note1)
• Heated water
a
• Premix Type I fluid (Note1)
• Mixture of water and Type I fluid
a
• Type II fluid, Type III fluid or Type IV fluid
• Premix Type I fluid
a
• Mixture of water and Type II fluid, Type III fluid or Type IV fluid
• Type II fluid, Type III fluid or Type IV fluid
a
Note 1: Fluids must be heated to ensure a temperature of 60°C minimum at the nozzle.
• Mixture of water and Type II fluid, Type III fluid or Type IV fluid Note: De-icing fluid is normally applied heated to ensure maximum efficiency.
7.1.2.1 De-Icing / Anti-Icing Checks
Following the de-icing/anti-icing procedures and prior to takeoff, the critical aeroplane surfaces shall be clean of all frost, ice, slush, and snow accumulations in accordance with the following requirements. For specific aeroplane types additional requirements may exist e.g. special clear ice checks, such as tactile checks on wings. These special checks are not covered by the contamination check. Aeroplane operators shall make arrangements for suitably qualified personnel to meet these requirements. General aeroplane requirements after de-icing/anti-icing
Wings, tail and control surfaces
Wings, tail and control surfaces shall be free of ice, snow, slush, and frost except that a coating of frost may be present on wing lower surfaces in areas cold soaked by fuel between forward and aft spars in accordance with the aircraft manufacturers published manuals. (Note1)
Pitot heads and static ports
Pitot heads and static ports shall be clear of ice, frost, snow and fluid residues.
Engines
Engine inlets, exhaust nozzles, cooling intakes, control system probes and ports shall be clear of ice and snow. Engine fan blades or propellers (as appropriate) shall be clear of ice, frost and snow, and shall be free to rotate.
Air conditioning inlets and exits
Air conditioning inlets and exits shall be clear of ice, frost and snow. Outflow valves shall be clear and unobstructed.
Landing gear and landing gear doors
Landing gear and landing gear doors shall be unobstructed and clear of ice, frost and snow.
Fuel tank vents
Fuel tank vents shall be clear of ice, frost and snow.
Fuselage
Fuselage shall be clear of snow, slush or ice. Frost may be present in accordance with the aircraft manufacturer’s manuals.
Nose / Radome Area and Flight Deck Windows
Any significant deposits of snow, slush, or ice on the windscreens or on areas forward of the windscreens shall be removed prior to departure. Heated flight deck windows will not normally require de-icing.
Note 1
Frost or any other contamination is not acceptable on the lower side of the horizontal stabiliser and elevator, unless specified otherwise in the AFM or other aircraft manufacturer's documentation.
Flight control check
1 1 0 2
A functional flight control check using an external observer may be required after de-icing/anti-icing depending upon aeroplane type (see relevant manuals). This is particularly important in the case of an aeroplane that has been subjected to an extreme ice or snow covering.
o d i L ©
Sheet 515542
LSY Standard (jetww)
General Part
22-SEP-2011
Meteorology
230
T E M
Post De-icing/Anti-icing Check
An aeroplane shall not be dispatched after a de-icing/anti-icing operation until the aeroplane has received the following visual check by a trained and qualified person. This check shall cover wings, horizontal stabilizer, vertical stabilizer and fuselage, plus all other parts of the aeroplane on which a de-icing/anti-icing treatment was performed according to the requirements identified during the contamination check. The check shall be performed from points offering sufficient visibility of all prescribed surfaces (e.g. from the de-icer itself or other equipment suitable for gaining access). Any contamination found, shall be removed by further deicing/anti-icing treatment and the check repeated. Before take-off the commander must ensure that he has received confirmation that this Post De-icing/Anti-icing Check has been accomplished. a
Where the de-icing provider is carrying out the de-icing/anti-icing process and also the Post De-icing/ Antiicing Check, it may either be performed as a separate check or incorporated into the de-icing operation as defined below. The de-icing provider shall specify the actual method adopted, where necessary by customer, in his winter procedures:
a
• As the de-icing/anti-icing operation progresses the De-icing Operator will closely monitor the surface receiving treatment, in order to ensure that all forms of frost, ice, slush or snow (except as may be allowed in the AFM and/or AMM) are removed.
a
• Once the operation has been completed, the De-icing Operator will carry out a close visual check of the surface where treatment commenced, in order to ensure it has remained free of contamination (this procedure is not required under ‘frost only’ conditions).
a
• Where the request for de-icing/anti-icing did not specify all of the following surfaces, i.e. wing, horizontal stabilizer, vertical stabilizer and fuselage, the surfaces omitted from the request shall also receive a close visual check at this time, in order to confirm that they have also remained free of contamination.
a
• Any evidence of contamination that is outside the defined limits shall be reported to the Commander immediately. Pre-takeoff Check
The Commander shall continually monitor the weather conditions after the performed de-icing/anti-icing treatment. Prior to takeoff he shall assess whether the applied holdover time is still appropriate and/or if untreated surfaces may have become contaminated. This check is normally performed from inside the flight deck. Pre-takeoff Contamination Check
This is a check of the critical surfaces for contamination. This check shall be performed when the condition of the critical surfaces of the aeroplane cannot be effectively assessed by a pre-takeoff check or when the applied holdover time has been exceeded. This check is normally performed from outside the aeroplane. The alternate means of compliance to a pre-takeoff contamination check is a complete de-icing / antiicing re-treatment of the aeroplane. Dried fluid residues when the aeroplane has not been flown after anti-icing
Dried fluid residue could occur when surfaces have been treated but the aeroplane has not subsequently been flown and not been subject to precipitation. The fluid may then have dried on the surfaces. In such situations the aeroplane must be checked for residues from de-icing / anti-icing fluids and cleaned as necessary. Proper account should be taken of the possible side-effects of fluid use. Such effects may include, but are not necessarily limited to, dried and/or re-hydrated residues, corrosion and the removal of lubricants. 7.1.2.2 Communication Procedure
Communication between the Commander and the de-icing crew will usually be achieved using a combination of printed forms and verbal communication. For treatments carried out after aeroplane doors are closed, use of flight interphone (headset) or VHF radio will usually be required. Use of hand signals is not recommended except for the final "all clear" signal. The procedural sequence as written below should be understood as a sample. Local procedures or detailed procedures established by the airline may differ. Communication prior to starting De-icing/Anti-Icing Treatment
• Before de-icing/anti-icing, the Commander shall be requested to confirm the treatment required (areas to be de-iced, anti-icing requirements, special de-icing procedures)
1 1 0 2
o d i L ©
Sheet 515543
*515543* LSY Standard (jetww)
General Part
T E M
22-SEP-2011 240
Meteorology
• Before fluid application starts, the Commander shall be requested to configure the aeroplane for deicing/anti-icing (surfaces, controls and systems, as per aeroplane type requirements) • The de-icing crew shall wait for confirmation that this has been completed before commencing the treatment. • For treatments carried out without the flight crew present, a suitably qualified individual shall be nominated by the aeroplane operator to confirm the treatment required and to confirm correct configuration of the aeroplane. Communication after De-icing/Anti-Icing Treatment
An aeroplane shall not be dispatched for departure after a de-icing/anti-icing operation until the Commander has been notified of the type of de-icing/anti-icing operation performed (Anti-icing Code). The Anti-icing Code shall be provided by a qualified person at the completion of the treatment, indicating that the checked surfaces are free of ice, frost, snow, and slush, and in addition includes the necessary information to allow the Commander to estimate the holdover time to be expected under the prevailing weather conditions. Anti-Icing Codes
The following information shall be recorded and be communicated to the Commander by referring to the last step of the procedure and in the sequence provided below: a
Example: A de-icing/anti-icing procedure whose last step is the use of a mixture of 75% of a Type II fluid and 25% water, commencing at 13:35 local time on 20 February 2011, is reported and recorded as follows: TYPE II/75; 13:35; 20 Feb 2011; Complete name of anti-icing fluid; "Post de-icing/anti-icing check completed". Anti-Icing Code Content
• the fluid Type; i.e. Type I, II, III, IV • the concentration of fluid within the fluid/water mixture, expressed as a percentage by volume
(Note1)
• the local time (hours:minutes), either - for a one-step de-icing / anti-icing: at the start of the treatment or - for a two-step de-icing / anti-icing: at the start of the second step (anti-icing) • the date (written: day, month, year) (Note 2) • the complete name of the anti-icing fluid (so called “brand name”) (Note3) • the statement "Post de-icing/anti-icing check completed” (Note 4) Note 1:
no requirement for Type I fluid
Note 2:
required for record keeping, optional for Commander notification
Note 3:
optional; for Type II and IV fluids only
Note 4:
For specific aircraft types, additional requirements exist e.g. special clear ice checks, such as tactile checks on wings. Additional confirmation for these checks is required
7.1.3 Types of Fluids 7.1.3.1 General
De-icing fluid is normally applied heated in order to assure maximum efficiency. Type IV fluid gives a longer hold–over time than Type II fluid if 100% is applied. At certain stations, Type II fluid is handled in such a way that its properties do not fulfill the specification. In these cases, the product can still be used but the Hold-Over Time Table for Type I fluid has to be applied. At some stations a dyed de-/anti-ice fluid might be sprayed. The dyed fluid is either a Type I or a Type IV fluid and assists ground personnel in conducting the final check. De-/anti-icing fluids do not provide any protection from contamination once the aircraft is airborne. 1 1 0 2
Special Type Fluids:
o d i L ©
Sheet 515543
LSY Standard (jetww)
General Part
20-OCT-2011
Meteorology
250
T E M
MIL-A8243-D de-/anti-icing fluids are also classified in Type I and Type II fluids. However, these fluids are entirely different to ISO/SAE classified Type I and Type II fluid and do not fulfil the ISO/SAE specification. Type 1 1/2 and Type 3 might still be available at some aerodromes. However, these fluids are not covered by any international specification, e.g. type 3 are still to be found in Canada. The following Types are qualified and approved de/anti-icing fluids. 7.1.3.2 Type I Fluids • Clariant Safewing DG I • Clariant Safewing MP I • SPCA DE-825 • SPCA DE-910 • UCAR ADF Concentrate • UCAR ADF 50/50 (ready to use and shall not be diluted further) • UCAR ADF XL54 (ready to use and shall not be diluted further) • BASF Aerex 102 • Lyondell ACRO Plu 7.1.3.3 Type II Fluids • Kilfrost ABC-3 • Clariant Safewing MP II1951 • SPCA AD-104 (must be stored unheated) • SPCA 104/N • Octagon Forty Below (must not be used in 75/25 dilution) • UCAR AAF ULTRA (must be stored and applied unheated)
7.2 Hold-Over-Time (HOT) Policy 7.2.1 General The following procedures and tables are recommended by AEA (Association of European Airlines). For HOT given, latest edition has been used. In general different company policies may apply as well as different tables in terms of types of precipitation are published by FAA and / or Transport Canada. Hold–over protection is achieved by a layer of anti-icing fluid remaining on the protected aircraft surfaces for a period of time. With a one-step de-/anti-icing, the HOT begins at the commencement of the de-/anti-icing. With a two-step procedure, the HOT begins at the commencement of the second step, which is the anti-icing step. Generally, the low end of the range represents the estimated HOT in heavy conditions, the high end, the estimated HOT in light conditions. In heavy weather conditions, the HOT can even be shorter than the lower end of the range. The HOT, however, is not applicable in case of a hail or ice pellets precipitation or if a mixture of 25% antiicing fluid and 75% water is sprayed. Note
It is the pilot’s decision to determine the HOT at a given concentration taking into account actual weather conditions.
CAUTION: De-icing/anti-icing fluids used during ground de-icing/anti-icing are not intended for - and do not provide - protection during flight.
Sheet 523826
*523826* LSY Standard (jetww)
1 1 0 2
o d i L ©
General Part
T E M
20-OCT-2011 260
Meteorology
7.2.1.1 Lowest Operational Use Temperature (LOUT): The Lowest Operational Use Temperature (LOUT) is the higher (warmer) of a) The lowest temperature at which the fluid meets the aerodynamic acceptance test for a given type (high speed or low speed) of aircraft; or b) The freezing point of the fluid plus the freezing point buffer of 10°C for Type I fluid and 7°C for Type II, III, or IV fluids. 7.2.2 One-Step- / Two-Step Guidelines 7.2.2.1 Type I Fluid Guideline for HOTs anticipated for ISO/SAE. Guidelines for the application of Type 1 Fluid/Water Mixtures (minimum concentrations) as a function of OAT One-Step Procedure
OAT
d
Two-Step Procedure
De-Icing/Anti-Icing
-3°C (27°F) and above
First Step: De-Icing
Second Step: Anti-Icing 1)
Heated water or a heated fluid/water mixture Heated fluid/water mixture with a freezing point of at least 10 °C (18 °F) below OAT
below -3°C (27°F) down to LOUT
Heated fluid/water mixture with a freezing point not more than 3°C (5°F) above OAT
Heated fluid/water mixture with a freezing point of at least 10 °C (18 °F) below OAT
Note 1:
Temperature of water of fluid/water mixtures shall be at least 60°C (140°F) at the nozzle. Upper temperature limit shall not exceed fluid and aircraft manufacturer's recommendations.
Note 2:
This table is applicable for the use of Type I Holdover Time guidelines. If holdover times are not required, a temperature of 60°C (140°F) at the nozzle is desirable.
Note 3:
To use Type I Holdover Time guidelines, at least 1 liter/m 2 (about 2 Gals/100ft 2) must be applied to the de-iced surfaces.
Caution:
Wing skin temperatures may be lower than OAT. If this condition is identified, a stronger mix (more glycol) may need to be used to ensure a sufficient freeze point buffer.
1)
To be applied before first step fluid freezes, typically within 3 minutes.
7.2.2.2 Type II, III and IV Fluids Guideline for the application of Type II, Type III, and Type IV fluid/water mixtures (minimum concentrations) as a function of OAT Concentration of neat fluid/water mixture in vol% / vol% OAT
1 1 0 2
1)
One-Step Procedure
Two-Step Procedure
De-Icing / AntiIcing
First step De-icing
Second Step AntiIcing 2)
-3°C (27°F) and above
50/50 heated 3) Type II, III, or IV fluid/water mixture
Heated water or a heated Type I, II, III or IV fluid/water mixture
50/50 Type II, III, or IV fluid/water mixture
below -3° to -14°C (27° to 7°F)
75/25 heated 3) Type II, III, 4) or IV fluid/water mixture
Heated Type I, II, III or IV fluid/water mixture with a freezing point not more than 3°C (5°F) above OAT
75/25 Type II, III 4), or IV fluid/water mixture
o d i L ©
Sheet 523826
LSY Standard (jetww)
General Part
22-SEP-2011 270
Meteorology
T E M
Concentration of neat fluid/water mixture in vol% / vol% One-Step Procedure
OAT 1)
below -14° to -25°C (7° to -13°F)
a
below -25°C (-13°F)
Two-Step Procedure
De-Icing / AntiIcing
First step De-icing
Second Step AntiIcing 2)
100/0 heated 3) Type II, III 4) or IV
Heated Type, I, II, III or IV fluid/water mixture with a freezing point not more than 3°C (5°F) above OAT
100/0 Type II, III 4), or IV
Type II, III, or IV fluid may be used below -25°C (-13°F) provided that the freezing point of the fluid is at least 7°C ( 13°F) below OAT and the aerodynamic acceptance criteria are met (LOUT). Note: Type II/Type III/Type IV fluid may not be used below -25°C (-13°F) in active frost conditions Consider the use of Type I fluid/water mixture when Type II, III, or IV fluid cannot be used
1)
Fluids must only be used at temperatures above their LOUT
2)
to be applied before first step fluid freezes, typically within 3 minutes
3)
clean aircraft my be anit-iced with unheated fluid
4)
Type III fluid may be used below -10°C (14°F) provided that the freezing point of the fluid is at least 7°C (13°F) below OAT and that aerodynamic acceptance criteria are met (LOUT)
Note :
For heated fluid and fluid mixtures, a temperature not less than 60°C ( 140°F) at the nozzle is desirable. When the first step is performed using a fluid/water mix with a freezing point above OAT, the temperature at the nozzle shall be at least 60°C and at least 1 liter/m² (~2 Gals/100ft²) must be applied to the surfaces to be de-iced. Upper temperature limit shall not exceed fluid and aircraft manufacturer's recommendations
Caution 1:
Wing skin temperatures may be lower than OAT. If this condition is identified, it shall be verified if a stronger mix (more glycol) may need to be used to ensure a sufficient freeze point buffer. As fluid freezing may occur, 50/50 Type II, III, or IV fluid shall not be used for the anti-icing step of a cold soaked wing as indicated by frost or ice on the lower surface of the wing in the area of the fuel tank.
Caution 2:
An insufficient amount of anti-icing fluid, especially in the second step of a two step procedure, may cause a substantial loss of holdover time. This is particularly true when using a Type I fluid mixture for the first step (de-icing).
Caution 3:
Some fluids shall only be used undiluted. For some fluids the lowest operational use temperature may differ. For details refer to fluid manufacturer's documentation.
7.2.3 HOT Active Frost Type I, II, III, and IV Fluids Guidelines for holdover times anticipated for Type I, II, III, and IV fluids mixtures in active frost conditions as a function of OAT (Valid for metallic and composite surfaces) Type II, III, and IV Fluid Concentration Neat Fluid Water Vol % / Vol %
OAT
°C
-1 and above
below 30 to 27
Type II3)
Type III3)
Type IV3)
100/0
8:00
2:00
12:00
75/25
5:00
1:00
5:00
3:00
0:30
3:00
100/0
8:00
2:00
12:00
75/25
5:00
1:00
5:00
50/50 below -1 to -3
Active frost Type I 1) 2)
°F
30 and above
Approximate Holdover Times under various weather conditions (hours : minutes)
0:35
1 1 0 2
o d i L ©
Sheet 515545
*515545* LSY Standard (jetww)
General Part
T E M
22-SEP-2011 280
Type II, III, and IV Fluid Concentration Neat Fluid Water Vol % / Vol %
OAT
°C
Approximate Holdover Times under various weather conditions (hours : minutes) Active frost Type I 1) 2)
°F
below -1 to -3
below 30 to 27
below -3 to -10
below 27 to 14
below -10 to -14
below 14 to 7
below -14 to -21 below -21 to -25
a
Meteorology
Type II3)
Type III3)
Type IV3)
50/50
1:30
0:30
3:00
100/0
8:00
2:00
10:00
75/25
5:00
1:00
5:00
6:00
2:00
6:00
75/25
1:00
1:00
1:00
below 7 to -6
100/0
6:00
2:00
6:00
below -6 to -13
100/0
2:00
2:00
4:00
100/0
0:35
1)
Type I fluid / water mixture is selected so that freezing point of the mixture is at least 10°C (18°F) below the OAT
2)
May be used below -25°C (-13°F) provided the lowest operational use temperature (LOUT) of the fluid is respected
3)
These fluids may not be used below -25 °C (-13 °F) in active frost conditions.
7.2.4 Various Weather Conditions Type I Fluid Guidelines for holdover times anticipated for Time I fluid mixture as a function of weather condition and OAT (Valid for metallic and composite surfaces) Approximate Holdover Times under Various Weather Conditions (hours:minutes)
OAT 1)
a
1 1 0 2
o d i L ©
Snow / Snow Grains/ Snow Pellets2)
Freezing Drizzle3)
Light Freezing Rain
Rain on Cold Soaked Wing 0:01-0:056)
°C
°F
Freezing Fog
-3 and above
27 and above
0:09-0:16
0:03-0:06
0:08-0:13
0:02-0:05
below -3 to -6
below 27 to 21
0:06-0:08
0:02-0:05
0:05-0:09
0:02-0:05
below -6 to -10
below 21 to 14
0:04-0:08
0:02-0:05
0:04-0:07
0:02-0:05
below -10
below 14
0:04-0:07
0:02-0:04
Other 4)5)
CAUTION: No Holdover time Guidelines exist
1)
Ensure that the Lowest Operational Use Temperature (LOUT) is respected.
2)
In light "Rain and Snow" conditions use "Light Freezing Rain" holdover times
3)
If positive identification of "Freezing Drizzle" is not possible use "Light Freezing Rain" holdover times
4)
Other conditions are: Heavy snow, ice pellets, hail, moderate freezing rain, and heavy freezing rain
5)
For holdover times under active frost conditions see the separate frost table
6)
No holdover time guideline exists for this condition for O°C (32°F) and below
Type I Fluids / Water Mixture is selected so that the Freezing Point of the mixture is at least 10°C (18°F) below actual OAT
Sheet 515545
LSY Standard (jetww)
General Part
22-SEP-2011 290
Meteorology
T E M
The time of protection will be shortened in heavy weather conditions. Heavy precipitaion rates or high moisture content, high wind velocity or jet blast may reduce holdover time below the lowest time stated in the range. Holdover time may also be reduced when the aircraft skin temperature is lower than OAT. Therefore, the indicated times should be used only in conjunction with a pre-takeoff check .
CAUTION:
7.2.5 Various Weather Conditions Type II Fluid
Guidelines for holdover times anticipated for Type II fluid mixtures as a function of weather conditions and OAT (Valid for metallic and composite surfaces) Type II Fluid Concentration Neat-Fluid/Water OAT1)
°C
Approximate Holdover Times under Various Weather Conditions (hours:minutes)
°F
c
-3 and above
27 and above
c
c
below -3 to -14 below -14 to -25 or LOUT
a
below 27 to 7 below 7 to -13 or LOUT
Vol %/ Vol %
Freezing Fog
Snow / Snow Grains / Snow Pellets2)
Freezing Drizzle3)
Light Freezing Rain
4)5)
100/0
0:35-1:30
0:20-0:45
0:30-0:55
0:15-0:30
75/25
0:25-1:00
0:15-0:30
0:20-0:45
0:10-0:25
50/50
0:15-0:30
0:05-0:15
0:08-0:15
0:05-0:09
100/0
0:20-1:05
0:15-0:30
0:20-0:45
0:10-0:20
7)
7)
0:15-0:30
0:080:157)
75/25
0:25-0:50
0:10-0:20
100/0
0:15-0:35
0:15-0:30
O t h e r
Rain on Cold Soaked Wing
7)
0:08 -0:406) 0:05-0:25 6)
CAUTION: No Holdover time guideline exist
1)
Ensure that the Lowest Operational Use temperature (LOUT) is respected. Consider the use of Type I fluid when Type II fluid cannot be used.
2)
In light "Rain and Snow" conditions use "Light Freezing Rain" holdover times
3)
If positive identification of "Freezing Drizzle" is not possible use "Light Freezing Rain" holdover times
4)
Other conditions are: Heavy snow, ice pellets, moderate and heavy freezing rain, hail
5)
For holdover times under active frost conditions see the separate frost table
6)
No holdover time guidelines exist for this condition for 0°C (32°F) and below
7)
No holdover time guidelines exist for this condition below -10°C (14°F)
CAUTION:
The time of protection will be shortened in heavy weather conditions. Heavy precipitaion rates or moisture content, high wind velocity, or jet blast may reduce holdover time below the lowest time stated in the range. Holdover time may also be reduced when the aircraft skin temperature is lower than OAT. Therefore, the indicated times should be used only in conjunction with a pre-takeoff check .
1 1 0 2
o d i L ©
Sheet 515546
*515546* LSY Standard (jetww)
General Part
T E M
22-SEP-2011 300
Meteorology
7.2.6 Various Weather Conditions Type III fluid
Guideline for holdover times anticipated for Type III fluid mixtures as a function of weather conditions and OAT (Valid for metallic and composite surfaces) Type III Fluid Concentration Neat-Fluid/Water OAT1)
°C
-3 and above
a
Approximate Holdover Times under Various Weather Conditions (hours:minutes)
°F
27 and above
below -3 to -10
below 27 to 14
below -10
below 14
Vol %/ Vol %
Freezing Fog
Snow / Snow Grains / Snow Pellets2)
Freezing Drizzle3)
Light Freezing Rain
100/0
0:20-0:40
0:10-0:20
0:10-0:20
0:08-0:10
75/25
0:15-0:30
0:08-0:15
0:08-0:15
0:06-0:10
50/50
0:10-0:20
0:04-0:08
0:05-0:09
0:04-0:06
100/0
0:20-0:40
0:09-0:15
0:10-0:20
0:08-0:10
75/25
0:15-0:30
0:07-0:10
0:09-0:12
0:06-0:09
100/0
0:20-0:40
0:08-0:15
Rain on Cold Soaked Wing
O t h e r
4)5)
0:06-0:20 6)
0:02-0:10 6)
CAUTION: No holdover time guideline exist
1)
Ensure that the Lowest Operational Use Temperature (LOUT) is respected. Consider the use of Type I fluid when Type III fluid cannot be used.
2)
In light "Rain and Snow" consider use "Light Freezing Rain" holdover times
3)
If positive identification of "Freezing Drizzle" is not possible use "Light Freezing Rain" holdover times
4)
Other conditions are: Heavy snow, ice pellets, moderate, and heavy freezing rain, hail
5)
For holdover times under active frost conditions see the separate frost table
6)
No holdover time guidelines exist for this condition for 0°C (32°F) and below
CAUTION:
The time of protection will be shortened in heavy weather conditions. Heavy precipitaion rates or moisture content, high wind velocity, or jet blast may reduce holdover time below the lowest time stated in the range. Holdover time may also be reduced when the aircraft skin temperature is lower than OAT. Therefore, the indicated times should be used only in conjunction with a pre-takeoff check .
1 1 0 2
o d i L ©
Sheet 515546
LSY Standard (jetww)
General Part
22-SEP-2011 310
Meteorology
T E M
7.2.7 Various Weather Conditions Type IV fluid
Guidelines for holdover times anticipated for Type IV fluid mixtures as a function of weather conditions and OAT (Valid for metallic and composite surfaces) SAE Type IV Fluid Concentration Neat-Fluid/Water OAT1)
°C
Approximate Holdover Times under Various Weather Conditions (hours : minutes)
°F
c
c
-3 and above
27 and above
c c
c
below -3 to -14
below 27 to 7
Freezing Fog
Freezing Drizzle 3)
Light Freezing Rain
Rain on Cold Soaked Wing
O t h e r 4)5)
100/0
1:20-3:10
0:35-1:15
0:45-1:30
0:25-0:40
75/25
1:00-1:45
0:30-0:55
0:35-1:05
0:25-0:35
50/50
0:15-0:35
0:07-0:15
0:10-0:20
0:07-0:10
100/0
0:20-1:20
0:25-0:50
0:20-1:00
0:10-0:25
75/25
0:25-0:50
0:20-0:35
100/0
0:15-0:40
0:15-0:30
7)
7)
0:15-1:00
0:10-0:25
7)
7)
0:10-1:15 6)
0:09-0:50 6)
CAUTION: No Holdover time Guideline exist
a
below -14 to -25 or LOUT
a
1)
Ensure that the Lowest Operational Use Temperature (LOUT) is respected. Consider the use of Type I fluid when Type IV fluid cannot be used
2)
In light "Rain and Snow" consider use "Light Freezing Rain" holdover times
3)
If positive identification of "Freezing Drizzle" is not possible use "Light Freezing Rain" holdover times
4)
Other conditions are: Heavy snow, ice pellets, moderate and heavy freezing rain, hail
5)
For holdover times under active frost conditions see the separate frost table
6)
No holdover time guidelines exist for this condition for 0°C (32°F) and below
7)
No holdover time guidelines exist for this condition below -10°C (14°F)
CAUTION:
below 7 to -13 or LOUT
Vol %/ Vol %
Snow / Snow Grains / Snow Pellets2)
The time of protection will be shortened in heavy weather conditions. Heavy precipitaion rates or moisture content, high wind velocity or jet blast may reduce holdover time below the lowest time stated in the range. Holdover time may also be reduced when the aircraft skin temperature is lower than OAT. Therefore, the indicated times should be used only in conjunction with a pre-takeoff check .
1 1 0 2
o d i L ©
Sheet 515547
*515547* LSY Standard (jetww)
T E M
General Part
22-SEP-2011 320
Meteorology
7.3 Adverse Runway Condition 7.3.1 Dissemination of RWY State Information
SNOWTAMs and RWY reports are only provided for winter conditions and not for other hazardous RWY conditions e.g. RWY slippery when wet or combined with dust. Observations and measurements are not made at routine intervals. Information on RWY state and braking conditions as contained in SNOWTAM are available from ATC and are usually broadcasted on ATIS. When giving landing information, the thirds of the RWY are referred to as first, second, and third part. Other information e.g. state of TWY, apron etc. are added. 7.3.2 SNOWTAM
The SNOWTAM is a specialized NOTAM notifying the presence of hazardous RWY condition due to snow, ice, etc. by using a specified ICAO format. It is available on the NOTAM or at the AIS office as soon as the presence of contamination is considered to be operationally significant. The closure of a RWY for clearance and the subsequent reopening may be notified by a NOTAM. ⇒
Meteorology General Information
8.5 SNOWTAM Decoding
7.3.2.1 Issue/Validity of SNOWTAMs
A new SNOWTAM should normally be issued every 6 HRs. For aerodromes with no night operation or closed at night, a new SNOWTAM should be promulgated 2 HRs before the aerodrome is reopened for operation. The validity of SNOWTAMs is maximum 24 HRs. If the validity expires, a new observation, measurement should be made even if conditions have not changed and a new SNOWTAM should be issued. 7.3.3 METAR Runway Report
RWY reports are provided in the abbreviated form of 8-figure groups appended to weather reports (METAR). These reports are derived from the SNOWTAM. For obvious reasons e.g. traffic density the half hourly rhythm of METARs is not practicable for RWY condition observations. Thus a repetition of the previous RWY report may mean that no significant change has occurred. If an aerodrome is closed due to snow or removal of snow and ice, the term SNOCLO may replace the 8-figure code group. ⇒
Meteorology General Information
8.1.1 Runway Report Decoding
7.3.4 Issue/Validity of RWY Reports.
RWY reports are based on the same observation/measurements as the SNOWTAM and are repeated with every subsequent weather report until a new RWY report is made. 7.3.4.1 Assessment of Deposit Water on the RWY
Whenever water is present on RWYs description of the conditions on the center half of the RWY should be made using the following terms: • DAMP - the surface shows a change of color due to moisture. • WET - the surface is soaked but there is no standing water. • WATER PATCHES - significant patches of standing water are visible. • STANDING WATER - standing water of significant depth and area which affects significantly the braking action (aquaplaning). • FLOODED - extensive standing water is visible during heavy rainfall. Snow and Slush on the RWY
• DRY SNOW - snow which can be blown if loose or, if compacted by hand, will fall apart again upon release. • WET SNOW - snow which, if compacted by hand will stick together and tend to form a snowball. 1 1 0 2
o d i L ©
• SLUSH - water saturated snow which with a heel and toe slap down motion against the ground will be displaced with a splatter.
Sheet 515547
LSY Standard (jetww)
General Part
12-MAY-2011 330
Meteorology
T E M
• COMPACTED SNOW - snow which has been compressed into a solid mass that resists further compression and will hold together or break up into lumps if picked up. Combination of Ice, Snow, and Standing Water
Such combinations, especially when rain sleet or snow is falling, may have a rather transparent appearance due to their high water / ice content, shall be considered as slush. Accuracy of Depth of Deposit
When dry or wet snow or slush is present on a RWY, an assessment of the mean depth should be made to an accuracy of approximately 2CM for dry snow, 1CM for wet snow and 3MM for slush. The depth of deposit of compacted / solid contaminants such as ice, compacted snow or frozen ruts or ridges which do not cause a drag (retarding rolling) is not considered to be operationally significant and needs not to be assessed and reported. The depth of standing water is very difficult to assess. Hence it is often reported as “not measurable”. ⇒
Meteorology General Information
8.1.1 Runway Report Decoding
Assessment of Extent of Runway Coverage
The extent of the coverage of the RWY reported in percent is the best possible estimate but shall not be understood to be an accurate measurement. Assessment of Braking Condition
Operation considerations require reliable and uniform reports on braking conditions whenever RWYs are contaminated and subsequent updating when conditions significantly change. The reported Friction Coefficient (FC) is a relative measure for the achievable friction of the tire to surface interface of a braked wheel and should be the maximum which occurs when a wheel is slipping but still rolling. Measurements should be made at a distance of 3m or the distance from the centerline where most operations take place. The reported Braking Action (BA) may reflect the FC converted to BA as well as subjective pilot reports or assessments by empirical methods. Therefore, for operation applications the FC is generally preferable to the BA which often lacks a proper standardized reference basis. If BA is reported it is recommended to request the FC if measured or, if the BA stems from pilot reports, to be informed on the aircraft type involved. The FC and especially the BA should not be taken as absolute due to the many methods of assessment used and the different variables such as aircraft weight, speed, landing technique, braking performance, tires, and undercarriage characteristics, etc. 7.3.4.2 Measuring Devices
All types of measuring equipment do not enable measurements with satisfactory reliability in aquaplaning conditions (standing water, slush, and wet snow) or if more than a thin layer of loose snow is present. In such cases the braking conditions should be reported as “unreliable”. When considering Friction Coefficients (FC) of wet RWYs, especially with smooth surface, it should be noted that the friction may drop markedly with increasing speed. Equipment Permitting Continuous Measurement. e.g:
• Surface Friction Tester (SFT) • Skiddometer SKH/SKL (high/low pressure) • Mu-Meter (MUM) • Grip Tester (GRT) • RWY Friction Tester (RFT) …can be used for friction values on compacted snow and ice covered RWYs.
1 1 0 2
Decelerometers, e.g.:
o d i L ©
Sheet 471336
*471336* LSY Standard (jetww)
T E M
General Part
12-MAY-2011 340
•
Meteorology
Tapley Meter (TAP)
• Dynometer …may be used on certain surface condition (compacted snow, ice, and very thin layers of dry snow). Decelerometers should not be used in loose snow or slush. Subjective methods permitting assessment of Braking Action (BA) only: Truck, car or pilot‘s report. The reliability of such reports is questionable. 7.3.4.3 Relationship Between Friction Coefficient (FC) and Braking Action (BA)
The table below was developed by ICAO based on measurements on ice and compacted snow. It states the relationship between FC and BA. It should not be taken to be absolute values and applicable in all conditions and should not be used to convert BA into FC. The relation between FC and empirically assessed BA is rather loose due to the lack of a proper standardized reference basis referring e.g. to the type of vehicle and its tires used, the pilot‘s experience, the aircraft type, and its performance in such conditions. Therefore the table should not be used to convert BA into FC. For operational purposes: Friction Coefficient
Estimated Braking Action
0.40 and above
GOOD
0.39 - 0.36
MEDIUM TO GOOD
0.35 - 0.30
MEDIUM
0.29 - 0.26
MEDIUM TO POOR
0.25 and below
POOR
Different relationships between Friction Coefficient and Braking Action may be applied by country rules and regulations, e. g. Canada and Russia. 7.3.4.4 Differences from ICAO Standard
I.e. Canada and Russia apply procedures different from ICAO Standard. For further details refer to respective RSIs and CRARs.
8 Decoding of Meteorological Data 8.1 TAF & METAR Decoding (ICAO) Italic information are for U.S. / Canada only. ⇒
North America MET
TAF & TREND Examples
3.1 USA / CANADA METAR / TAF. METAR, SPECI Examples
Decoding METAR / TREND, SPECI & TAF
TAF TAF AMD/COR
METAR, SPECI METAR/SPECI COR
Data type designator: TAF or TAF amended/corrected. METAR, SPECI, or METAR/SPECI corrected
EDDF
EDDF
Aerodrome: ICAO 4-letter location indicator
160900Z
160950Z
Date and time: TAF=issue of forecast, METAR/SPECO = actual time of observation (day of the month and time (HRs and MIN)
1 1 0 2
o d i L ©
Sheet 471336
LSY Standard (jetww)
General Part
12-MAY-2011 350
Meteorology TAF & TREND Examples
METAR, SPECI Examples
T E M
Decoding METAR / TREND, SPECI & TAF
0606/1624 0812/0918
Auto
Validity of TAF (Days and period of the validity of the forecast in UTC). Validity of TREND : 2 HRs (Australia 3 HRs) from observation time METAR/SPECI: AUTO if report from fully automated STN
19018KT VRB03KMH 27016G30KT 140P99KT
35006KMH 000000KT 11027G45KT 340V050 140P199KMH
Mean wind and gusts in degrees true and KT or KMH VRB = variable; 00000 = calm G = gusts, maximum wind during the last 10 MIN V = fluctuating (variable)wind direction P = more than 100KT or 199KMH
CAVOK
CAVOK
CAVOK : 1) VIS ≥ 10km; 2) No clouds below 5000ft or highest MS, no CBs/TCUs, 3) no significant weather as given under Forecast/present weather (details shown at the end of this table)
0350, 7000 9000, 9999 4SM, 11/2SM
0050, 1600 8000, 9999 13/8SM, P6SM 0800NE 7000NDV
Visibility: TAF = prevailing VIS; METAR/SPECI prevailing VIS or MIN VIS (in meters: 0000 = 1600m R plus Runway designator: L = Left, R = Right, C = Center Qualifier: M = less than …., P = more than …., Fluctuating RVR V: maximum and minimum RVR Recent tendency: U = Up, D = Down, N = no change Recent tendency in Canada only R15/0300ft/D
+RA, SN, FG, -SHSN, HZ NSW
VCSH, FZRA, +SHRASN -SN
Forecast / present weather in 2-letter ABB (see below) Intensity: -=light, no sign = moderate, + = heavy NSW = cessation of sign. Weather given in preceding part of TAF
VV000, VV002 VV001, VV///
VV000, VV300 VV/// Vertical visibility VV in hundreds of feet: VV000 < 100 VV001
View more...
Comments
