A340 Cold Weather Operation

A340 COLD WEATHER OPERATIONSA340 COLD WEATHER OPERATIONSA340 COLD WEATHER OPERATIONSA340 COLD WEATHER OPERATIONSA340 COLD WEATHER OPERATIONSA340 COLD WEATHER OPERATIONSA340 COLD WEATHER OPERATIONSA340 COLD WEATHER OPERATIONSA340 COLD WEATHER OPERATIONSA340 COLD WEATHER OPERATIONS

Introduction

• Aircraft performance is certified on the basis of a cleanwing. Ice accretion affects wing performance. When thewing is clean, the airflow smoothly follows the shape ofthe wing. When the wing is covered with ice, the airflowseparates from the wing when the Angle-Of-Attack (AOA)increases. Therefore, the maximum lift-coefficient isreduced. As a result, the aircraft may stall at a lowerAOA, and the drag may increase.

• Even a small amount of ice and snow on the wings canreduce the stall AOA (and therefore increase the stallspeed) dramatically. A stall may occur before any stallwarning device signals it.

• The flight crew must keep in mind that the wingtemperature of the aircraft may be significantly lowerthan 0 °C, after a flight at high altitude and lowtemperature, even if the OAT is higher than 0 °C.

• In such cases, humidity or rain will cause ice accretionon the upper wing, and light frost under the wing. (Only3 mm of frost on the under-surface of the wing isacceptable.)

“ In all circumstances it is the Captain’s responsibility todecide whether or not to de-ice/anti-icing the aircraft, orto order a repeated treatment.• Having stated the above, the Captain relies heavily onthe ground engineers and the contractor who treats andinspects the aircraft surfaces.

• A340 is certified for flight in icing conditions.

DEFINITIONS

Icing Conditions

1. OAT (on ground and for takeoff) or the TAT (in flight)is 10 °C or below and

2. Visible moisture in the air (such as clouds, rain, fogwith low visibility of one mile or less, snow, sleet, icecrystals) or standing water, slush, ice or snow on therunways and taxiways.

Warning Pilots must turn on the engine anti-ice system,when temperature and visible moisture meet thesecriteria, and not wait until they see ice build up.

Freezing Conditions The conditions in which the OAT isbelow +3°C (37.4°F) and visible moisture in any form(such as fog with visibility below 1.5 km, rain, snow,sleet or ice crystals) or standing water, slush, ice or snowis present on the runway.

Critical Surfaces: wings (leading edges +upper surfacesof wings) & control surfaces (vertical & horizontalstabilizers, slats & flaps).

De-icing is a process by which frost, slush, snow or ice isremoved from the aircraft in order to provide cleansurfaces.

Anti-icing is a precautionary process which providesprotection against the formation of frost or ice andaccumulation of snow or slush on treated surfaces of theaircraft for a limited period of time (hold-over time).

De/anti-icing is a combination of de-icing and anti-icingand may be performed in one or two steps.

De-ice Fluids mixes with the ice on the surfaces, lowersthe freezing point of the ice so it melts and falls off withthe excess de-ice fluid (which is sprayed under pressure).

Anti-ice Fluids:

_ The fluids lowers freezing point of precipitation on a/csurfaces. Contains ethylene glycol or propylene glycol,etc, plus wetting agent, corrosion inhibitor, water andsometimes dye (so you can see it).

_ The fluids used for de-icing as well as for anti-icing.Depending on their characteristics, anti-icing fluids aredivided into different types with quite different anti-icingproperties:

_ De-icing fluid is normally applied heated in order toassure maximum efficiency.

_ De/anti-icing fluids do not provide any protection fromcontamination once the ACFT is airborne.

These fluids have different characteristics:

type I: Low viscosity/ Limited HOT/ Mainly for deicingtype II, III, IV: High viscosity/ Longer HOT/ Used for

deicing +anti-icing

Type I fluids form a thin liquid wetting film, which gives arather limited Hold-Over Time (HOT).

In precipitation, they are quickly diluted and give short HOT. TypeI fluids are always mixed with water. The fluid/water mixture isselected to maintain freezing point at least 10°C below OAT.Increasing the fluid concentration does not improve HOT.

Type II fluids contain a thickener and form a thicker filmadhering to aircraft surfaces. Therefore, compared toType I, the Type II fluids provide improved HOT especiallyunder precipitation.

Before liftoff, the viscosity is drastically reduced by shear forces,allowing the fluid to run off the wing. Type II fluids are usedundiluted or diluted with water and are identified according to themixture ratio; e.g. “Type II 75" is a mixture of 75% (by volume)Type II fluid with 25% water. Higher concentrations allow usedown to lower temperatures and improve HOT.

Type IV fluids are similar to Type II, but provide even better HOTwhen used undiluted or slightly diluted.

Hold-Over Time (HOT)

_ HOT is the estimated time the anti-icing fluid willprevent frost, ice and snow to form or accumulate on theprotected (treated) areas of the aircraft. HOT starts atbeginning of the final anti-icing treatment (or de-icingfluid is only using the 1-step procedure). _ Hold–over protection is achieved by a layer of anti-icing fluidremaining on the protected a/c surfaces for a period of time.

_ A HOT table is published in RM/ PFL p.240, giving HOT asfunction of applied fluid, temperature and weather. For eachcondition the table gives a range of HOT (e.g. 30-45 minutes)

_ Generally, the low end of the range represents the estimatedHOT in heavy conditions, the high end, the estimated HOT in lightconditions.

_ In heavy weather conditions, the HOT can even be shorter thanthe lower end of the range and it is the responsibility of the P-i-Cto determine what HOT can be expected under prevailingconditions.

_ HOT may shortened with high wind velocity, jet blast and a/cskin temp well below OAT. If the aircraft is treated and remainswithin the HOT there is still no guarantee of clean surfaces – theHOT is a guide. HOT is determined from tables in the RM/ PFLWinter Ops considering fluid type and ratio mix, nature andseverity of precipitation.

PRE-FLIGHT & ENGINE STARTING

Pre-flight Check 1

_ All surfaces of the aircraft must be clear of snow, frost,


and ice for takeoff.

_ Thin hoarfrost is acceptable on the upper surface of thefuselage (Thin hoarfrost is typically a white crystallinedeposit which usually develops uniformly on exposedsurfaces on cold and cloudless nights; it is thin that aperson can distinguish surface features (line or markings)beneath it).

_ On the underside of the wing tank area, a max layer of3 mm (1/8 inch) will not penalize takeoff performance.

_ Other than above, all parts of the aircraft must be freeof ice, snow and slush. Other areas to inspect:

• landing gear assemblies, tires, gear doors• engine inlet cowls, fans (check for rotation), fan exhaust ducts and reverser assemblies• drains, bleeds, outlets• pitots, static ports, TAT sensors, angle of attack sensors• radome• fuel vents• commercial water supplies not frozen

_ Use ground power for APU start if OAT ≤ -15°C (5°F).

_ Cold soak effect: OAT -2 to +15°C, ice or frost canform on a/c structure if airframe is below 0°C.

_ ECAM and EFIS DU’s may not be available with OATbelow -15°C (5°F) until cabin conditioning has warmedthe avionics compartment and cockpit IRS’s may take upto 15 minutes to alignment.

_ Freezing temp of JET-A1 is -47 °C and slightly higherfor other common fuels. Add warm fuel if necessary.

_ The PROBE/WINDOW HEAT switch is turned on in thepreflight (PNF duty) for cold weather procedures – temp≤0°C (otherwise left in AUTO which is lights out).

Engine Start

_ Minimum oil temperature for starting is -40°C.

_ The PROBE/WINDOW HEAT switch is turned back toAUTO after engine start. It provides a low level of heatingto the cockpit windows and some probe heating. Thelevel of heating automatically changes to high whenairborne. The TAT probe is not heated on the ground.

_ EAI goes on after all engines started (PNF duty beforeAPU shut-down).

DE-ICING & ANTI-ICING TREATMENT

Before departure the following actions shall be performedbefore every departure:

_ The departure check person shall perform a check forneed to de-ice. The P-i-C shall, if applicable incooperation with the departure check person, state thenecessary de-/anti-icing treatment of the aircraft or beassured that there is no frost, ice or snow on the criticalsurfaces of the aircraft If de-icing performed:

– The de-/anti-icing release person shall perform a checkafter de-/anti-icing verifying that all frost, ice and snowaccumulations are removed from the critical surfaces ofthe aircraft after completed treatment.

Note If conditions are such that frost, ice or snow mightaccumulate on the aircraft: – After anti-icing, the P-i-C shalldetermine the HOT for prevailing conditions. See DeterminedHold-Over Time (HOT) table. The P-i-C or a delegated personshall perform a Pre-takeoff Check within 2 min before takeoff.

_ Usually performed after engine start so as to :

+ maximize HOT+ prevent de-/anti-ice fluid from entering the cabin through open doors

_ Coordinate with ATC at busy airports regards adeparture slot time so de/anti-icing may be done at thesuitable time to extend HOT.

_ During off-gate de-icing, two-way communicationbetween pilot and de/ anti-icing operator/ supervisormust be established prior to de/anti-icing treatment. Thisshall be accomplished either by intercom or by VHF radio.

_ The mixture ratio and de-icing procedure (1–step/ 2–step) is selected by the de-icing specialist. The selectionof mixture ratio is based on the actual weather conditionsand ISO/ SAE tables.

_ The PIC usually has no influence on selection ofmixture ratio and de-icing procedure. Should the PIC,however, insist on a mixture or procedure other than thatselected by the de-icing specialist, he is obliged to reportthe reason to personnel in charge.

_ All de/anti-icing actions must be entered in the a/c log.The appropriate information will be communicated by theground personnel and the respective de/ anti-icing code(fluid type, mixture and the time the final de/ anti-icingstep commenced, e.g. ”Type II, 75/25, 1155”), shall beentered by the flight crew into the Technical Log on the”Complaint” side of the log slip.

_ The HOT table must only be used as a guideline, asmany factors affect the time of protection of the aircraft.

_ Aircraft preparation for fluid spraying: See theprocedure in FCOM 3.04.91 Supp Tech –Adverse Weather-Cold Weather.

_ The following outlines the various procedures to beapplied before and after spraying:

+ All ENG and APU BLEED pushbutton must be set to OFFand the DITCHING pushbutton must be set to ON, toprevent any engine ingestion of deicing/anti-icing fluid.

+ The aircraft can be deiced/anti-iced, with the engineand/or the APU running or off. However, the APU or theengine should not be started during spraying. (De-iceand anti-ice fluid should not be sprayed directly intoengine or APU intakes or any other vent.)

+ The aircraft must be same deiced/anti-iced treatmentsymmetrically on both sides.

+ If spraying is performed with the engines not running,a small negative cabin delta P may appear for a shorttime, just after selecting the ditching pushbutton to OFF.During this time, do not open any door or windows.

De-/anti-icing Treatment

Depending upon the severity of the weather, thedeicing/anti-icing procedure must be applied in one ortwo steps either:

+ In one step, via the single application of heated anddiluted deicing/anti-icing fluid. The fluid used to de-icethe aircraft remains on the treated surfaces and providesanti-icing capability.: This procedure provides a shortHOT, and should be used in low moisture conditions only.The HOT starts from the beginning of the application ofthe fluid.

1 Step Procedure Heated anti-icing fluid applied Type I , II & IVfluid. (type III fluid discontinued) Type I less effective and usedfor low precipitation case only .

+ In two steps, by first applying the heated de-icing


fluid, then by applying a protective anti-icing fluid. Thesecond step (anti-icing) is an over spray with hot or coldanti-icing fluid. The correct fluid and concentration shallbe chosen with regard to desired HOT, OAT or aircraftskin temperature (whichever is lowest) and prevailingweather conditions. These two sprays must be appliedconsecutively. The HOT starts from the beginning of theapplication of the second fluid.

2 Step Procedure De-ice with either hot water, mixture of hotwater & type I fluid (low viscosity and shorter H.O.T), or heatedconcentrate of type I fluid applied. Then anti-ice with type II ortype IV fluid (high viscosity an longer HOT) applied.

_ If repeated anti-icing is necessary, ground crew mustde-ice the surfaces with a hot fluid mixture beforeapplying a new layer of anti-icing fluids

_ Aircraft wings are sprayed first.

After Treatment Check 2 / Check 4

_ Keep the APU running with the bleed off for a fewminutes after completion of spraying and perform avisual inspection of the aircraft surfaces.

_ The slats/flaps and flight controls can be moved,because they no longer have ice.

_ A deicing/anti-icing report must be filled out to indicatethe type of fluid and when the spraying began.

_ The information from ground personnel who performedthe treatment must include:

+ Type of fluid used.+ The mix ratio of fluid to water.+ When the HOT began.+ Result of post application check.

TAXI OUT & BEFORE TAKE-OFF

Taxiing

_ On contaminated taxiways, the taxiing speed should belimited to 10 knots on straight way ( max 5 kts aroundcorners -less in icy conditions), and any action that coulddistract the flight crew during taxiing should be delayeduntil the aircraft is stopped.

_ On slush-covered, or snow-covered, taxiways: Flapselection should be delayed until reaching the holdingpoint, in order to avoid contaminating the flap/slatactuation mechanism. Then do the “before takeoffchecklist down to the line” when reaching the holdingpoint.

_ Avoid high thrust settings.

_ Allow more than usual spacing with taxiing aircraft infront and begin braking for a stop well before normal (~3times earlier).

_ Anti skid does not operate at speeds below 10 knots.

_ The use of EAI increases ground idle thrust, so the pilotmust use care on slippery surfaces..

_ To minimize the risk of skidding during turns: Avoidlarge tiller inputs and use minimum radius turns.

_ Use smooth nose wheel steering inputs.

_ On slippery taxiways: It may be more effective to usedifferential braking and/or asymmetric thrust, instead ofnose wheel steering.

_ Warm up procedure When on ground in icing conditionsat idle and in temperature below + 1°C (34°F) forextended periods of time, or if engine vibration occurs,

thrust should be increased 50% N1 for ten secondsperiodically (do this once every hour) and just priorbefore takeoff, to shed any ice from the fan blades.

Pre-takeoff Check Check 3

Pre-takeoff check is the P-i-C's final check that theaircraft is free from frost, ice and snow before takeoff. Itshall be performed within 2 minutes of commencingtakeoff roll whenever conditions are such that frost, iceand snow might have accumulated on the criticalsurfaces after the de-/anti-icing treatment.

Mental review: A mental review of prevailing conditionsincluding:

1. Anti-icing treatment and HOT 2. Precipitation type and rate and variations experienced since anti-icing was performed.3.Temperature, normally OAT but also skin tempif aircraft has been cold soaked. 4. Relation of temperature/dew point. 5. Wind or experienced jet blast (especially for Type I fluid). 6. Visual cues as available from flight deck.

Check of representative surface : A visual check of arepresentative surface from within the flight deck. ThePre-takeoff Check is passed satisfactorily if:

+ The determined HOT has not expired, and + It is visually confirmed that the representativesurface is free from frost, ice and snow.

Check of wings: A visual check of wings. It may benecessary to open flight deck windows or perform thecheck from the cabin. The Pre-takeoff Check is passedsatisfactorily if:

+ The determined HOT has not expired, and + The visual check confirms that wings are free from frost, ice and snow.

_ If it cannot be satisfactorily confirmed by the Pre-takeoff Check, the aircraft shall return for a new de-/anti-icing.

4 CHECKs BEFORE TAKEOFF4 CHECKs BEFORE TAKEOFF4 CHECKs BEFORE TAKEOFF4 CHECKs BEFORE TAKEOFF4 CHECKs BEFORE TAKEOFF4 CHECKs BEFORE TAKEOFF4 CHECKs BEFORE TAKEOFF4 CHECKs BEFORE TAKEOFF4 CHECKs BEFORE TAKEOFF4 CHECKs BEFORE TAKEOFF

“MAKE IT CLEAN AND KEEP IT CLEAN”

Check 1 for need to de-ice : A visual check of theentire aircraft to determine whether the de-icing isrequired.

Check 2 after de-ice/anti-ice treatment: A check toverify that frost, ice and snow has been completelyremoved out and the anti-icing treatment has beenperformed correctly. This is done by the authorizedperson who performs the treatment and issues the de-ice/anti-ice release statement.

** Check 3 pre-takeoff check ** : The check isperformed before every departure as an item in thedeparture check.

_ This check is the P-i-C's final check that the aircraft( wings or a representative surface) is free from frost, iceand snow before takeoff. It shall be performed within 2minutes of start commencing takeoff roll wheneverconditions are such that frost, ice and snow might haveaccumulated on the aircraft after the de-/anti-icingtreatment.

_ Done by flight crew within the determined HOT frominside cabin to ensure wings & control surfaces clear ofice, snow, slush & frost.

_ If there are only two pilots and one has to leave the


control seat on the flight deck to check the wings thenthe aircraft must be stopped and the park brake set.

_ Switch on all aircraft lighting at night. Check as closeas possible to T/O.

_ If in doubt or the surfaces can’t be properly evaluated,get an external inspection (even it means taxiing back tothe ramp).

_ Special attention should be given to the flight controlcheck, which is delayed until just before take-off.

_ Before Take-off Checklist is completed at the holdingpoint.

Check 4 if re treatment is required : it is requiredwhen HOT has expired. HOT may be extended dependingon weather conditions (see the charts in RM).

TAKEOFF

_ Before the aircraft lines up on the runway for takeoff,the flight crew must ensure that the airframe has no iceor snow. Then, before applying thrust, the Captain shouldensure that the nosewheel is straight on the runway.

_ On contaminated runways use TOGA thrust.

_ ENG START SEL to IGN/START for takeoff in turbulence,standing water or heavy rain.

_ Takeoff technique is normal.

_ Take-off is not recommended from a runway which is:+ icy (though can land under certain conditions)+ has more than 2” (50 mm) of loose dry snow+ has more than 1” (25 mm) of wet snow+ has more than 1/2” (12 mm) of slush (no tables available for calculations)

Takeoff Performance

_ V1 (VR and V2) reductions apply for contaminatedrunways – see FCOM 2.04.10

_ Use of EAI and/or WAI results in a reduction in PERFMTOW, the flight crew must apply the applicableperformance penalty.

_ Crosswind limits apply for contaminated runways withreduced braking Action (see limitations below)

_ Anti-skid must be serviceable (contaminated RWY)

_ Inoperative brakes may affect dispatch (contaminatedRWY)

_ Reversers must be serviceable (contaminated RWY)

_ When taking off from contaminated runways, it is notpermitted to use FLEX thrust. However, derated thrustmay be used, as required, in order to optimize aircraftperformance. When available, a derated takeoff thrustresults in lower minimum control speeds and, therefore,in a lower V1.

_ A reduction in the minimum control speeds cansometimes enhance takeoff performance.

_ Slush, standing water, and/or deep snow reduce theeffectiveness of aircraft takeoff performance, because ofincreased rolling resistance and reduction in tire-to-ground friction.

_ A higher flap setting increases the runway-limitedtakeoff weight, but reduces the second segment limitedtakeoff weight.

_ Low visibility take-off (if required) has a set of

limitations also.

Takeoff roll

_ If there is a tendency to deviate from the runwaycenterline, this tendency must be neutralizedimmediately, via rudder pedal steering, not via the tiller.

_ On contaminated runways, the flight crew shouldensure that engine thrust advances symmetrically to helpminimize potential problems with directional control.

Rejected Takeoff

_ Maintain directional control with rudder and differentialbraking if necessary.

_ Reverse thrust is most useful at high speeds.

CLIMB & DESCENT

_ Whenever icing conditions are encountered orexpected, the EAI should be turned on. Although the TATbefore entering clouds may not require EAI, flight crewsshould be aware that the TAT often decreasessignificantly, when entering clouds.

_ In climb or cruise, when the SAT decreases to lowerthan -40 °C, EAI should be turned off, unless flying nearCBs.

_ If the recommended anti-ice procedures are notperformed, engine stall, over-temperature, or enginedamage may occur.

_ If it is necessary to turn on the EAI, and if ice accretionis visible because EAI was turned on late, then apply thefollowing procedure:

+ Set the ENGINE START selector to IGN.+ Retard one engine, and turn on set the EAI. + Smoothly adjust thrust, and wait for stabilization.+ Set the ENGINE START selector to NORM+ Repeat this procedure for the other engines.

_ WAI should be turned on, if either severe ice accretionis expected, or if there is any indication of icing on theairframe.

HOLDING & APPROACH

Caution (FCOM 3.04.30)

1. The pilot should avoid extended flight in icingconditions with the slats extended.

2. If the pilot suspects that a significant amount of ice isaccumulating on unde-iced parts of the airframe, the minspeed should be:

_ Green Dot + 10 kt in clean configuration.

3. If the pilot suspects that a significant amount of ice isaccumulating on de-iced parts (WAI inoperative) of theairframe, use CONF 3 for landing, and the minimumspeed should be:

_ Green Dot + 10 kt in clean configuration._ VLS + 5 kt in CONF 1,2,3. _ Multiply the landing distance by 1.1 on dry runway or 1.05 on a wet runway.

Holding

_ Holding in icing conditions should be done with a cleanwing.

_ If holding is performed in icing conditions, the flightcrew should maintain clean configuration. This is becauseprolonged flight in icing conditions with the slats


extended should be avoided.

Approach

_ If significant ice accretion develops on parts of the wingthat have not been de-iced, the aircraft speed must beincreased (see above).

_ When the temperature is lower than ISA -10°C , thetarget altitudes (provided by the ATC) must be corrected,by adding the values. ( see cold weather altitudecorrections below)

LANDING & TAXI IN

Landing

_ Consider autobrake mode 4 for short or contaminatedrunways ( mode LO,2,3 for long and dry runways).

_ Consider contaminated runway matters for landing.Landing distance calculations and technique, crosswindlimits.

_ Do not land on a contaminated runway if the antiskid isunserviceable.

_ Do not land on a runway where braking action isreported as POOR unless a greater emergency exists.

_ Correct flare technique (do not float).

_ Maintain directional control with the rudder for as longas possible and then use nosewheel steering with care.

_ Obviously, landings should be avoided on very slipperyrunways. However, if it is not possible to avoid suchlandings, the following factors (linked to operations oncontaminated runways) should be considered:

. Braking action

. Directional control.

Braking Action

_ The presence of fluid contaminants on the runway has anadverse effect on braking performance, because it reduces thefriction between the tires and the surface of the runway. It alsocreates a layer of fluid between the tires and the runway surface,and reduces the contact area.

_ The landing distances, indicated in the QRH, provide a goodassessment of the real landing distances for specific levels ofcontamination.

_ A firm touchdown should be made and MAX reverse should beselected, as soon as the main landing gear is on ground. Usingreversers on a runway that is contaminated with dry snow mayreduce visibility, particularly at low speeds. In such cases, reversethrust should be reduced to idle, if necessary.

_ The use of autobrake mode 4 for A345,346 is recommended,when landing on an evenly contaminated runway. It is possiblethat the DECEL light on the AUTO BRK panel will not come on, asthe predetermined deceleration may not be achieved. This doesnot mean that the autobrake is not working.

_ In the case of uneven contamination on a wet or contaminatedrunway, the autobrake may laterally destabilize the aircraft. Ifthis occurs, consider deselecting the autobrake.

Directional Control

_ During rollout, the side stick must be centered. This preventsasymmetric wheel loading, that results in asymmetric braking andincreases the weathercock tendency of the aircraft.

_ The rudder should be used for directional control aftertouchdown, in the same way as for a normal landing. Use of thetiller must be avoided above taxi speed, because it may result innosewheel skidding, and lead to a loss of directional control.

_ When required, differential braking must be applied bycompletely releasing the pedal on the side that is opposite to theexpected direction of the turn. This is because, on a slippery

runway, the same braking effect may be produced by a full orhalf-deflection of the pedal.

_ Landing on a contaminated runway in crosswindrequires careful consideration. In such a case, directionalcontrol problems are caused by two different factors:

+ If the aircraft touches down with some crab, and reverse thrust is selected, the side-force component of reverse adds to the crosswind component, and causes the aircraft to drift to the downwind side of the runway.+ As the braking efficiency increases, the cornering force of the main wheels decreases. This adds to any problems there may be with directional control.

_ If there is a problem with directional control:+ Reverse thrust should be set to idle, in order to reduce the reverse thrust side-force component.+ The brakes should be released, in order to increase the cornering force.+ The pilot should return to the runway centerline, reselect reverse thrust, and resume braking.

Taxi In

_ After landing in slow, slush or ice do not retract theflaps. The engineer must inspect them for iceaccumulation or damage and will retract the flaps. GREENand YELLOW ELEC PUMPS are placed ON temporarily toretract the flaps.

_ If the approach was made in icing conditions, or if therunway was contaminated with slush or snow, theflaps/slats should not be retracted until after engineshutdown, and after the ground crew has confirmed thatflaps/slats are clear of obstructing ice. This is becauseretraction could cause damage, by crushing any ice thatis in the slots of the slats.

_ When the aircraft arrives at the gate, and the enginesare stopped, a visual inspection should be performed tocheck that the slats/flaps areas are free ofcontamination. They may then be retracted, with theelectric pumps.

PARKING & SECURING

At the end of the flight, in extreme cold conditions, coldsoak protection is requested when a longer stopover isexpected.

_ Remove the APU battery in very cold conditions – below-15°C (it can Freeze otherwise).

_ Drain water systems to prevent freezing and possiblysplit pipes. The water draining procedure is in FCOM.

_ Aircraft external vents and ports are closed e.g.DITCHING P/B ON).

_ Park brake should be left off (chocks in).

_ pitot and other protective covers ON.

AIRCRAFT SYSTEM

Engine Anti-Ice (EAI)

_ Descent with anti-ice - The FMGCS assumes anti-ice ison for a third of all descents.

_ If anti-ice use is prolonged, increase descent speed (tothat programmed) or use half speedbrake.

Wing Anti-Ice (WAI)

_ When switched ON on the ground, anti-ice valves open


for about 30 seconds (test sequence) and then close aslong as the aircraft on ground until airborne.

_ Detection by+ ECAM “SEVERE ICE” or+ ice accretion on central external cockpit post o+ Ice accretion on the windscreen wiper or window external frame Wing anti-ice is only the outer portion of the leading edge slat.

Equipment Failure Cases

_ EAI valves remain OPEN if electrical failure (fail safeopen)._ WAI valves CLOSE if electrical failure (fail safe close).

BRAKING ACTION vs RUNWAY CONDITION vs XWIND

The concept of equivalent runway condition is used todetermine the max crosswind limitation.

The following table indicates the max recommendedcrosswinds related to the reported braking actions:

Braking action/ Rwy Friction Coefficient/ Equivalent rwy condition/ Max Xwind kt

GOOD 1 32 GOOD/MEDIUM 0.39-0.36 1 27 MEDIUM 0.35-0.30 2/3 20 MEDIUM/POOR 0.29-0.26 2/3 20 POOR ≤0.25 3/4 15 UNRELIABLE *** 4/5 5(*** do not land unless a greater emergency exists)

Equivalent Runway Condition1 = dry, damp or wet runway (less than 3 mm depth

standing water)2 = slush3 = dry snow4 = standing water (with aquaplaning risk) or wet snow5 = icy runway or high risk aquaplaning

ALTIMETER CORRECTIONS

The altimeter is designed for ISA temperatures. When itis extremely cold, the altimeter under-reads (mostdangerous case). It is worse as altitude increases. Thismeans corrections to cleared altitude, minima, marker /DME check heights and glideslope intercept altitudesmust be applied.

_ The altimeter error may be significant under conditionsof extremely cold temperature.

_ Altimeter corrections during approach (The table iscalculated for a sea level AP. They are conservative whenapplied at higher AP). It is assumed that the aeroplanealtimeter reading on crossing the fix is correlated withthe published altitude, allowing for altitude error andaltimeter tolerances.

The choice of a method depends on of the amount ofprecision needed for the correction.

1. Approximate correction :

Increase obstacle elevation by 4% per 10°C below ISA ofthe height above the elevation of the altimeter settingsource or

Decrease aircraft indicated altitude by 4% per 10°Cbelow ISA of the height above the elevation of thealtimeter setting source

_ This method is generally used to adjust minimum safealtitudes and may be applied for all altimeters settingsource altitudes for temperatures above -15°C.

Example: Let’s assume an airport elevation of 1000 ft.The airport elevation is the same as altimeter settingsource altitudes elevation = 1000 ft.The ISA temperature at 1000 ft is 13°C.Let’s now assume that the actual OAT is -2°C.The ISA deviation is then, ΔISA =(13°C)-(-2°C) = -15°C.It is assumed that the minimum required actual altitudeto clear the obstacle is 1200 ft.Value to be added:In order to account for the ISA deviation, the terrain/obstacle elevation has to be increased by: 1200 x 0.04 x15/10 = 72 ftIn other words, the altimeter must read 1272 ft in orderto have an actual height of 1200 ft.

2. Tabulated corrections ICAO publishes the following tables in the «PANS-OPSFlight Procedures» manual. They are based on an airportelevation of 2000 ft; however, they may be usedoperationally at any airport.

Example: Aerodrome elevation: 1000 ft; Reported temperature:-40°C

References

1. FCOM 3.04.91 -Supplementary Techniques

- Adverse Weather - Cold Weather

2. FCOM 3.04.30 -Ice & Rain Protection

3. FCTM 04.010 – Adverse Weather

4. FOM 3.2.12 De/Anti-icing

5. Getting to Grips with Cold Weather Operations

6. Lido RM part LAT, PFL7. www.a330jam.com

edit by punn33567 [email protected] 14 Nov 08

A340 Cold Weather Operation

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Transcript of A340 Cold Weather Operation