clearance, but in mountainous areas,account will also be taken of itsDH Facilities/RVRFull Intermediate Basic Nil200 550 700 800 1000201–250 600 700 800 1000251–300 650 800 900 1200301 + 800 900 1000 1200Onshore Precision Approach Minima—Cat 1 FacilitiesDH(ft) Full Intermediate Basic200 500 600 1000201–250 550 650 1000251–300 600 700 1000301 + 750 800 100068 Operational Flyingheight and effect on turbulence.Remember the minimum RVR is800 m.Circling height will be in the AirwayManual, precalculated to a standardformula; otherwise, just add 300 feetto the highest obstacle within 5 nmof the airfield (provided the result isabove 500 feet agl).You can get a reasonably accuratecircling visibility in metres bymultiplying the circuit speed in knotsby 20, that is, if speed = 120 knots,then visibility must be 2400m. Youshould not descend below minimauntil aligned with the runway, exceptdown to 500 feet agl on base leg atyour discretion if you have the wholeof the runway continuously in sight.The minimum MDH and visibilityfor visual manoeuvring are 250 ftand 800m for helicopters, and as perthis table for aeroplanes:Aircraft Category A B C DMDH (ft) 400 500 600 700Min Met Vis (m) 1500 1600 2400 3600Visual ApproachThe minimum RVR for a visualapproach is 800 m (1200 in Canada).Aerodromes Without Approach AidsIf your destination doesn't have anyaids (unserviceability, perhaps), youcan either fly to your destination inVMC, or under IFR to where youcan carry out an InstrumentApproach, then continue under VFRto your original destination, whichmust be within 25 miles.In the latter case, permission mustbe obtained from ATC at the letdown point, and forecast weatherbetween the two aerodromes mustbe better than 1000 ft cloudbase agland 3 nm visibility. This also meansthat if you don't maintain the aboveVFR conditions, you will be flyingbelow 1000 feet above DecisionHeight en route, or if you're over thesea, actually below DH where youshould really be under an approachban (see glossary). You should notbe below MSA unless you canidentify your position, and sinceyou're flying towards an aerodromewithout approach aids, you couldfind that difficult. Your Companymay apply some rules in this case,but you will more than likely have toapply your own.Airborne Radar Approach (ARA)—Helicopters OverwaterYou cannot undertake one unlessyour radar is good enough toprovide course guidance for obstacleclearance (cloud ceiling must also besuitable for a safe landing). Beforestarting, a clear path must exist on
the screen for the final and missedapproach segments. If lateralclearance from any obstacle will beless than 1 nm, you should eitherapproach to a nearby target structureand proceed visually, or make theapproach from another directionleading to a circling manoeuvre.Minimum Descent Height (MDH)This is determined from a radioaltimeter. It must be at least 200 ftby day and 300 ft by night. TheMDH for an approach leading to acircling manoeuvre shall be at least300 ft by day and 500 ft by night.Minimum descent altitude (MDA)May only be used if the radioaltimeter is unserviceable, and shallbe at least MDH + 200 ft, based ona calibrated barometer at theOperational Procedures 69destination or the lowest forecastQNH for the region.Decision range (DR)At least ¾ nm unless you canconvince the CAA otherwise.Visual referenceYou cannot continue an approachbeyond DR or below MDH/MDAunless you are visual with thedestination.Single pilot operationsThe MDH/MDA for a single-pilotARA shall be 100 ft higher than theabove—DR is not less than 1 nm.An ARA to a rig or vessel under wayis only permitted for multi-crew.Heliport Minima for VFR/IFR,Onshore/OverwaterWhen VFR, if you are slow enoughto see other traffic and obstacles intime, that is, get a 1 minute visualreference ahead at 120 knots, theinflight visibility should be at least 2nm. Out of sight of land, flightvisibility must be at least 1500 mduring daylight and 5 km by night.VFR En-Route MinimaHelicoptersOn land, helicopters should have aminimum cloud-base of 600 feet agl(1500 feet at night) and 1000mvisibility (3 km). In reduced visibility,adjust your airspeed to maintain a 1-minute visual reference ahead, e.g. at120 knots, the inflight visibilityshould be at least 2 nm. A US Armystudy indicates that it takes about 5seconds to perceive a problem, makea decision and start a correction. At80 kts TAS, therefore, you will move676 feet and get still closer as youturn away from an obstacle, thedistance being equal to the radius ofthe turn which, in this case, wouldbe 984 feet, assuming 30 degrees ofbank, giving you a total distance of1660 feet to cope with, which is notgood if your visibility is only 1000feet! So, in bad weather, slow down,certainly enough to give you a 2-minute visual reference.Flying VMC on top of cloud is notallowed because performance rulesrequire that, if an engine fails, youmust remain in sight of the surface,and be able to carry out a safe forcedlanding, but in twins it may beundertaken by non-InstrumentRated pilots if the cloud within 10nm of the destination is forecast to
be less than 5/8 at 1000 feet with aminimum visibility of 1000m (VFROTT is only allowed with a permit inCanada). The forecast should bevalid from take-off until 2 hoursafter ETA. DO NOT LOSE SIGHTOF THE GROUND AT ALL INTHE ARCTIC.Do not start Special VFR below 3km, or conduct it below 1½ km.Over waterWhen crossing estuaries, it's agood idea to see the other sidebefore leaving the side you'reon, so you get as little of thegoldfish-bowl effect as possible.Also, keep the shoreline in sight.Out of sight of land, visibilitymust be greater than 1500m byday and 5 km by night.Single-Engined AeroplanesIf an engine fails, you must be ableto continue at or above MSA to1000 feet above a place on land where70 Operational Flyingyou can make a safe forced landing.Since you will be gliding, flightabove cloud extending below MSAis not a good idea. You need 1000 ftcloud-base agl (1500 over water or atnight) and 3 km visibility at all times.Multi-Engined AeroplanesFor minima, aeroplanes come in 5speed categories, based on nominalthreshold speeds, defined as 1.3times the stalling speed in thelanding configuration, or 1.23 timesVS 1G for JAR 25 certificatedaeroplanes, at max certificatedlanding mass.The five categories are:Category Threshold Speed (Kts)A Less than 91B 91 to 120C 121 to 140D 141 to 165E 166 to 210A and B can operate under VFRbetween 3-5 km visibility in Class Gairspace if the IAS is below 140 kts.Special VFR flights shall not becommenced when the visibility isless than 3 km, and not otherwiseconducted when less than 1½ km.All flights must be conducted inaccordance with Rules 24-27 of theRules of the Air.Presentation and Application ofOperating MinimaIf your flight guide does not containthe information you need for aparticular aerodrome, the detailsmust be included in your flight brief.For precision approaches, this willbe in terms of Decision Height (orDecision Altitude when landing onQNH) and RVR. For non-precisionapproaches, it will be MDH (orAltitude for QNH settings) andRVR. For circling, the MinimumDescent Height/Altitude will beshown together with a minimum inflight visibility (IFV).You can always operate to higherminima at any time in the interestsof safety, and you must always beprepared to amend the intendedminima if the status of any aidchanges, which brings me back tothe previous idea about havingsomething up your sleeve.Altitude Correction
Pressure altimeters indicate truealtitude under ISA conditions, sowhere the temperature is higher, truealtitude will be higher than shownand vice versa (errors may besignificant in extremely lowtemperatures).Interpreting MeteorologicalInformationSome codes (e.g. for wind velocity)use the same figures as the valuesbeing reported, so a wind from 280°at 15 knots is 28015KT. Otherwise,lettered abbreviations are used, asdescribed below.METARsRoutine actual weather reports(METARs) are compiled half-hourlyor hourly while the met station isopen. Missing information may beindicated by oblique strokes.Horizontal VisibilityThe minimum is in metres,followed by one of the eightpoints of the compass if there isa difference in visibility bydirection, as with 4000NE. Ifthe minimum visibility isOperational Procedures 71between 1500-5000 m inanother direction, minimum andmaximum values, and theirdirections will be given, e.g.1400SW 6000N. 9999 means 10km or more, while 0000 meansless than 50 metres.Runway Visual Range (RVR)An RVR group has the prefix Rfollowed by the runwaydesignator, then an obliquestroke followed by the touchdown RVR in metres. If RVR isassessed simultaneously on twoor more runways, it will berepeated; parallel runways aredistinguished by L, C or R, forLeft, Central or Right parallelrespectively, e.g. R24L/1100R24R/1150. When the RVR ismore than 1500m or themaximum that can be assessed,the group will be preceded by P,followed by the lesser value, e.g.R24/P1500. When less than theminimum, the RVR will bereported as M followed by theminimum value, e.g.R24/M0050.CloudUp to 4 cloud groups may beincluded, in ascending order ofbases. A group has 3 letters forthe amount (FEW = 1 to 2oktas, SCT, or scattered = 3 to 4oktas; BKN, or broken, = 5 to 7oktas, and OVC, or overcast = 8oktas) and 3 for the height ofthe cloud base in hundreds offeet above aerodrome level.Apart from significantconvective clouds (CB) cloudtypes are ignored. Cloud layersor masses are reported so thefirst group represents the lowestindividual layer; the second isthe next individual layer of morethan 2 oktas; the third is thenext higher layer of more than 4oktas, and the additional group,if any, represents significantconvective cloud, if not alreadyreported, e.g. ‘SCT010 SCT015SCT018CB BKN025’.
CAVOK and SKCCAVOK will replace visibility,RVR, weather and cloud groupswhen visibility is 10 km or more,there is no cloud below 5000feet or below the highest MSA,whichever is greater, and no cunims; with no precipitation,thunderstorm, shallow fog orlow, drifting snow. Otherwise,the cloud group is replaced by‘SKC’ (sky clear) if there is nocloud to report.Air Temperature and DewpointShown in °C, separated by anoblique stroke. A negative valueis indicated by an ‘M’ in front ofthe appropriate digits, e.g. 10/03or ‘01/MOI’Pressure SettingQNH is rounded down to thenext whole millibar and reportedas a 4-figure group preceded by‘Q’. If less than 1000 Mb, thefirst digit will be ‘0’.Recent WeatherSignificant weather since theprevious observation, but notcurrent, will be reported withthe standard present weathercode preceded by the indicator‘RE’, e.g. ‘RETS’.72 Operational FlyingWindshearIncluded if windshear isreported in the lowest 1600 feet,beginning with ‘WS’: ‘WSTKOF RWY20’, ‘WS LDGRWY20’.Runway StateFor snow or other runwaycontamination, an 8-figuregroup may be added at the endof the METAR.TrendFor when significant changes areforecast during the next 2 hours.The codes ‘BECMG’(becoming) or ‘TEMPO’(temporarily) may be followedby a time group (in hours andminutes UTC) preceded by oneof ‘FM’ (from), ‘TL’ (until) or‘AT’ (at). These are followed bythe expected change usingstandard codes, e.g. ‘BECMGFM 1100 250/35G50KT’ or‘TEMPO FM 0630 TL08303000 SHRA’. Where nosignificant changes are expected,the trend group will be replacedby the word ‘NOSIG’.DENEBFog dispersal is in progress.Aerodrome Weather Forecasts (TAFs)These describe forecast conditions atan aerodrome for between 9 and 24hours. The validity periods of manylonger forecasts may not start for upto 8 hours after the time of origin,and the details only cover the last 18hours. 9-hour TAFs are updated andre-issued every 3 hours, and 12- and24-hour TAFs, every 6 hours, withamendments issued as and whennecessary. They are not available foroffshore operations. A TAF may besub-divided into 2 or more selfcontained parts by the abbreviation‘FM’ (from) followed by the timeUTC to the nearest hour, expressedas 2 figures. Many groups inMETARs are also found in TAFs,
but differences are noted below:Validity PeriodA METAR reports conditions ata specific time, but the TAFcontains the date and time oforigin, followed by the start andfinish times of its validity periodin whole hours UTC, e.g. ‘TAFEGLL 130600Z (date and timeof issue) 0716 (period of validity0700 to 1600 hours UTC).Horizontal VisibilityOnly minimum visibility isforecast; RVR is not included.WeatherIf no significant weather isexpected, this is omitted. After achange group, however, if theweather ceases to be significant,the abbreviation ‘NSW’ (nosignificant weather) is inserted.CloudFor clear sky, the cloud groupwill be replaced by ‘SKC’ (skyclear). When no CB, or cloudbelow 5000' or the highest MSA,whichever is greater, areforecast, but ‘CAVOK’ or ‘SKC’are not appropriate, ‘NSC’ (nosignificant cloud) is used instead.Significant ChangesIn addition to ‘FM’ and the time(see above) significant changesmay be indicated by ‘BECMG’(becoming) or ‘TEMPO’Operational Procedures 73(temporarily). ‘BECMG’ isfollowed by a four-figure groupindicating the beginning andending of the period when thechange is expected. The changeis expected to be permanent,and to occur at an unspecifiedtime within it. ‘TEMPO’ willsimilarly be followed by a 4-figure time group, indicatingtemporary fluctuations inforecast conditions. ‘TEMPO’conditions are expected to lastless than 1 hour in eachinstance, and in aggregate, lessthan half the period indicated.ProbabilityProbability of a significantchange, either 30 or 40%. Theabbreviation ‘PROB’ willprecede the percentage,followed by a time group, or achange and time group, e.g.‘PROB 30 0507 0800FGBKN004’, or ‘PROB40TEMPO 1416 TSRABKN010CB’.AmendmentsThe amended forecast will haveAMD between TAF and theaerodrome identifier, and willcover the rest of the validityperiod of the original forecast.Fuel, Oil and Water MethanolFuel and oil consumption rates andweights for flight planning should bein Part B (the Flight Manual). It'susual to keep a check on the fuelcontents during flight to see if thingsare going according to plan, thuskeeping track of fuel consumption;it’s written down on the FlightProgress Log (PLOG) every hour orso on long trips, but not required(for obvious reasons) in singleengined unstabilised helicopters.Special conditions apply under IFR
and, needless to say, you shouldn'tthink of going IMC on VMC fuelreserves, talking of which….IFRJourneys are split into specificphases, such as start, checks, and taxi(that is, before take off), take-off andclimb (another phase), cruise anddescent (yet another), approach andlanding, plus 10%, plus missedapproach and diversion to thealternate. Then there's holding at thealternate, unuseable and contingencyfuel, which covers errors in forecastwinds, navigation, ATC restrictionsand individual variations fromstandard fuel consumption. Byarrangement, block figures can beused which ignore the take-off andclimb. Fuel flow will have to beadjusted if you plan to usespecialised equipment in flight, suchas heaters, or not use anythingessential, such as an engine. Moreabout Critical Points and Points ofNo Return against "wet footprints"are in International Operations.HelicoptersHelicopters don't need aerodromes,and minimum figures reflect this.However, they are calculated forlevel aircraft. Odd attitudes, saywhen slinging, may cause a fuelboost pump to become uncoveredand give you a nasty surprise justwhen you don’t want it. On a 206,the unuseable fuel after a boostpump failure can be up to 10 USgals, which is uncomfortably close tothe figures below. By day, use theIFR ones as above, but withoutmissed approach and loiter fuel, and74 Operational Flyingthe contingency fuel can be 5% ifover non-hostile terrain, and 10%otherwise (non-hostile in thiscontext means where fuel isavailable). By night, add loiter fuelas well.Final Reserve FuelAn emergency exists when your fuelhas reduced to the point where youshould land without delay. This is atleast the sum of:·
for VFR by day, 20 minutes atbest range speed;·
for IFR, or VFR and navigatingby other means than visuallandmarks or at night, 30minutes at holding speed at1500 ft above the destinationheliport in ISA, based on theestimated mass on arrival above·
extra fuel, at your discretion.This total is what you should haveleft when you arrive at yourdestination.Isolated HeliportsWhere an alternate does not exist thefuel required is the sum of:·
taxy fuel·
trip fuel·
contingency fuel·
additional fuel if required, butnot less than 2 hours' worth,based on normal cruiseconsumption over thedestination, or 45 mins forpiston-engines, plus 15% ofplanned cruise time.·
extra fuel, at your discretion.
Fixed WingThe plan should be to arrive overthe destination in a position to makean approach, overshoot and fly to analternate, and still have enough tohold for 45 minutes (30 if a turbojet) at the alternate. Even then, youmust still be able to carry out anapproach and landing, so you shouldcarry enough for the estimated timeto the destination, plus 5% forcontingencies, time to alternate, andholding fuel, which may be a setminimum amount, not forgetting thestart up and unuseable fuelallowances for type.Fuel PlanningBased on figures in the FlightManual, or data from the CompanyFuel Consumption Monitoring Programme,if you've got one, from whichcontingency fuel is calculated, thefuel on board at the start of eachflight must cover the elements listedbelow. Sometimes this can meanconsiderable forward thinking—forexample, fuel for a there-and-backtrip means considering Max LandingWeight at the first destination, howmuch you can accept when you getback (so you don't need to defuel fora heavy load next time) and whetheror not you can claim tax drawbackfrom Customs.Standard ProcedureThe fuel required is the sum of:·
Taxy Fuel, that is, the totalamount you expect to usebefore take-off, including icesystems and the APU.·
Trip Fuel, including take-off andclimb for the expecteddeparture routeing, cruise fromtop of climb (TOC) to top ofOperational Procedures 75descent (TOD), TOD to initialapproach point according to theexpected arrival procedure, andapproach and landing atdestination.·
Contingency Fuel, which must bethe higher of:·
5% of planned fuel or thatfor the rest of the flight,reduced to 3% with enroute alternate, or·
fuel for 20 minutes, basedon the planned trip fuel,supported by data from theFCMP, or·
fuel for at least 15 minshold at 1500' above thedestination in ISAsupported by data fromFCMP, or·
5 mins hold at 1500' abovethe destination in ISA.·
Alternate Fuel, to include·
a go-around to missedapproach altitude, based onthe procedure·
climb from missedapproach altitude tocruising level·
cruise from TOC to TOD.·
TOD to initial approachpoint, based on theexpected arrival procedure·
approach and landing at thealternate.
With two alternates, use thefigures for the one that needsthe most fuel. The departurepoint can be used as analternate.·
Final Reserve Fuel, or enough for45 minutes for a piston-enginedaeroplane, or 30 minutes at1500 ft above aerodromeelevation in ISA for turbo-propsand turbo-jets, based on theestimated landing weight.·
Additional Fuel, dictated by theoperation, e.g. ETOPS. Onlyneeded if the fuel calculatedabove is not enough for 15 minsholding at 1500 ft above theaerodrome in ISA (when IFR)without an alternate, andfollowing an engine orpressurisation failure at themost critical point en-route,covering descent as necessary toa suitable aerodrome, 15minutes hold at 1500 ft in ISAand approach and landing.·
Extra fuel, at your discretion.Decision Point ProcedureFor an en-route decision point thefuel required is the greater of:For the destination·
taxy fuel·
trip fuel, via the decisionpoint.·
contingency fuel of at least5% of estimated fuel fromdecision point todestination.·
alternate fuel, if required.·
Final reserve fuel.·
additional fuel, if required76 Operational Flying·
extra fuel, at yourdiscretion.For the alternate·
taxy fuel·
trip fuel via the decisionpoint.·
contingency fuel of not lessthan 3% of the trip fuel.·
final reserve fuel.·
additional fuel, if required.·
extra fuel, at yourdiscretion.Isolated Aerodrome ProcedureWhere an alternate does not exist thefuel required is the sum of:·
taxy fuel·
trip fuel·
contingency fuel (seeStandard Procedure, above).·
additional fuel if required,but at least 2 hours' worth,based on normal cruiseconsumption over thedestination, or 45 mins forpiston-engines, plus 15% ofplanned cruise time.·
extra fuel, at yourdiscretion.Predetermined Point ProcedureWhere the distance between thedestination and alternate means youcan only go through a predeterminedpoint, use the greater of:For the destination·
taxy fuel·
trip fuel to the destinationvia predetermined point.
·
standard contingency fuel.·
additional fuel if required,but not less than 2 hours'worth, based on normalcruise consumption overthe destination, or 45 minsfor piston-engined aircraft,plus 15% of planned cruise.·
extra fuel, at yourdiscretion.For the alternate·
taxy fuel·
trip fuel from the departureaerodrome to the alternate,via predetermined point.·
standard contingency fuel..·
additional fuel if required,but at least 45 mins forpiston-engined aircraft, or30 mins hold at 1500 ft inISA including Final reservefuel for turbo-props andturbo-jets·
extra fuel, at yourdiscretion.OilJust check before flight that theengine has been topped upaccording to the manufacturer’srecommendations, and that noexcess oil consumption has takenplace between flights.Operational Procedures 77Water MethanolSee the Flight manual.Mass and Centre of GravityLoading presents similar problemsfor all aircraft, but heavier types willhave things like Maximum Zero FuelWeight to contend with, aside fromlarger areas in which to place loadsand present more chances formistakes to happen. Some aircrafthave a proper cargo fit, butproblems arise where one thatnormally carries passengers is usedwithout modification, which is whyyou may need to be certificated onyour training forms as being clearedto change the aircraft layout.Naturally, in small aircraft where theemergency exits are obvious, thisreally only involves removing theseats, because the aim is just tosubstitute loads that use the samefixtures and locations, but where youget involved in removing galleys andotherwise converting the cabin inlarger ones, the exercise becomes alittle more difficult (just because aFlight Manual contains details offreight loading limitations, don’tassume that any modifications youmake are permitted—those figuresmay only have been used for basiccertification).There are two aspects to Loading,the weights and their distribution,and you sometimes get some nastysurprises—fuel in wings meansunusually shaped fuel tanks, so youwon't get a straight line variation;every fuel load will have a differentfigure, principally because the fueltanks have a C of G system all oftheir own, running separately fromthe aircraft. In this case, it's notenough just to subtract the closingfuel moment from the start—forexample, say 1000 lbs has a momentof 1843 and 300 has 558. The result
