000 feet PA, but maintaining cabinpressure altitudes below that.Flight CrewEach member of the flight crew shallhave:Operational Procedures 135·
an oxygen mask withinimmediate reach, which may bethe same one as above,excluding the portableapparatus. When above 25 000feet, the mask must be a quickdonning type.·
when cabin pressure fails,oxygen for the time the cabinaltitude exceeds 10 000 feet,with a minimum of 30 minutesfor aircraft below 25 000', and 2hours for those above.·
essential flight crew membersmust use oxygen continuouslyafter 30 minutes at a cabin PAover 10 000 feet, and at all timesoverhighest skills from crews and placingthe most strain on the aircraft.Because of this, strict regulationsgovern the information used forcalculating take-off or landingperformance. Of course, in the olddays (say during the war, or whenthe trains ran on time), havingenough engines to lift the load was136 Operational Flyingall that mattered and no priority wasgiven to reserves of power and thelike. Now it's different, andperformance requirements will beworked out before a C of A isissued, over a wide range ofconditions. They are subsequentlyincorporated in the Flight Manual,which actually forms part of the C ofA. In addition, the ANO requiresyou to ensure that your aircraft hasadequate performance for anyproposed flight.Aircraft are certified in one ofseveral groups (A, A (Restricted), orB for helicopters, or A B C D E or Ffor aeroplanes); the higher theperformance of the aircraft, thelower the alphabetical letter (a 737comes under Performance A, forinstance, while anything up to 9 seatsthat may require a forced landingafter engine failure will come underF). Well, at least, that’s how theANO works. JAR does it differentlyas we have already seen.The group in which an aircraftoperates depends on itsCertification, Max All-Up Weightand the number of passengers itcarries. Within these limits you canchoose which group to operate in,and come under the appropriateweather and weight limitations; itmay be more acceptablecommercially, for example, tooperate in a lesser group if it enablesyou to take more payload, and makemore money – all you might need islonger runways.Individual aircraft of a given specieswill vary in performance due to suchvariables as the age of the airframeand engines, the standard ofmaintenance, or the skill andexperience of the crews. What youcan do on one day under a given setof circumstances may well beimpossible another time. Theoriginal testing, of course, is donewith new aircraft and highlyexperienced pilots. These results areunfactored, and not all performancedata for foreign aircraft is actuallyverified by the CAA, though they docarry out spot checks. In fact, anyfigures are a mixture of actualreadings and calculated (orguesstimated) adjustments fromthem. The "performance" of anaircraft is therefore a set of averagevalues—particular machines may bebetter or worse.There are fudge factors applied tounfactored figures to produce netperformance (and gross performance whenthey're not). Occasionally,performance data (as amended bythe CAA) in a flight manual willalready be factored, but you willhave to check the small print on thechart, in case they surprise you.Figures and graphs are based onStandard conditions which allow forfixed reductions in pressure andtemperature with height. As we allknow, the real world isn't like that,so these assumptions may not alwaysbe true and due allowance musttherefore be made for them (if youraircraft is performing sluggishly, youmay find it's not the machine, butthe conditions it has to work underthat are at fault).Performance A aircraft must (withone engine out) clear all obstaclesunder the departure track within adefined area by a specified margin,
without relying on seeing andavoiding them – in Canada, forexample, aircraft are expected toclimb at over 200 feet per nm from aOperational Procedures 137point 35 feet above the end of therunway, because obstacles areassessed inside a slope of 152 feetper nm, which gives you a clearanceof 48 feet (if there are no obstacles,the takeoff visibility can also belower). All the relevant data will bein the graphs, but some groups haveno information at all in some areas.For instance, an aircraft inPerformance Group C is assumed tohave all engines working until above200 feet, under which height there isno data for landing or take-off(which is why the take-off minimawill rarely be below this, because youmust be visual to avoid any obstaclesshould an engine fail). Sometimes,there can be no specific provisionfor engine failure at all.Each group requires certainconditions to be met, either instandards of power available,environment or special procedures.For example, take-off, landing andreject areas need to be preparedsurfaces for Class A helicopters,which also have to achieve certainnet gradients at particular points inthe climb. Lower groups are morerelaxed, but still have limitations—you need somewhere to land inemergency, but for these you onlyneed to avoid risk to third partieswhile meeting certain weather limits.Keeping to the helicopter theme,Class A (1) take-off proceduresinvolve a vertical and backwardsliftoff to a predetermined heightbefore going forward, which isknown as the Critical Decision Point(or CDP), and gives you a choice ofaction if an emergency happens(actually, ICAO now call it theTakeoff Decision Point, or TDP).Having moved backwards, you stillhave the take-off spot in sight andit's therefore available for landing. AtCDP (or TDP), if you elect to carryon to forward flight, you should beable to clear the landing spot duringthe steep dive you have to make toachieve flying speed (that's why theCDP is about 40 feet high). Thingshappen in reverse on landing. Thisprocedure is not without its critics,since prolonged hovering at highengine power outputs is not goodengine handling.Anyhow, whatever you're flying, youwill find the data needed to checkyour performance in the FlightManual, which will have a UKsupplement if your aircraft is foreignmade—these override anyinformation in the standard manuals.General principles concerningdistances for take-off and landing aresimilar for aeroplanes andhelicopters; for example, take-offdistances for both will increase by10% for each 1000-foot increase inPressure Altitude.Some factors affecting performanceinclude:Density AltitudeThis is is the altitude at which the
ISA density is the same as that of theair in question or, in other words,your real altitude resulting from theeffects of height, temperature,pressure and humidity, all of whichcan make the air thinner and whichare mentioned below. The detailswill be in the Flight Manual,although humidity is usually ignoredin the average performance chart,because it has more to do withengine power than aerodynamicefficiency, and high air density andhumidity do not often go hand in138 Operational Flyinghand. However, if the air is humid,say after a good shower, you wouldbe wise to be careful.Anyhow, the idea is that the morethe density of the air decreases forany reason, the higher your aircraftthinks it is. If you look at the liftformula, you will see that the liftfrom a wing or thrust from apropeller is directly dependent on airdensity, as is drag, of course. Theeffects are as valid at sea level as theyare in mountainous areas whentemperatures are high – for example,90° (F) at sea level is really 1900' asfar as your machine is concerned. Inextreme circumstances, you mayhave to restrict your operations toearly morning or late afternoon.Here is a handy chart:°F/C 60/15.6 70/21.1 80/26.71,000’ 1300 2000 27002000’ 2350 3100 38003000’ 3600 4300 50004000’ 4650 5600 63005000’ 6350 6900 76006000’ 7400 8100 88007000’ 8600 9300 1,00008000’ 9700 10400 111009000’ 11,000 11600 124001,0000’ 12250 13000 1360011,000’ 13600 14300 1500012000’ 14750 15400 16000It shows that, at 6,000 feet and 21°C,for example, you should enterperformance charts at 8100 feet.If you want to work it out foryourself, try this formula:DA = 145,3660.235)]where X is the station pressure ininches divided by the temperature inRankin degrees, which are found byadding 459.69 to Fahrenheit totals.AltitudeAir density drops off by .002 lbs percubic foot (i.e. 2½ %) for every1000 feet in the lower layers of theatmosphere.HumidityAdding water vapour to air makes itless dense because the molecularweight is lower (dry air is 29 –watervapour is 18). On cold days,humidity is less of a problem simplybecause cold air holds less vapour. Arelative humidity of 90% at 70°Fmeans twice as much than at 50°F.TemperatureAs heat expands air, it becomesthinner. Thinner air is less dense(Boyles Law). On the surface, anincrease in temperature will decreasedensity and increase volume, with
pressure remaining constant. Ataltitude, however, pressure reducesmore than temperature does, andwill produce an apparentcontradiction, where temperaturewill decrease from the expansion.PressureAir density reduces with atmosphericpressure (Charles Law). When youcompress air, its density increases.Runway lengthDetails are declared by the AirportAuthority and published in the AIP.This declared distance is either theTake-off Run Available (TORA) orLanding Distance Available (LDA).Any areas at the ends unsuitable torun on, but nevertheless clear ofobstacles, are called Clearways, which,with the TORA, form the Take-offOperational Procedures 139Distance Available (TODA), whichshould not be more than 1½ xTORA.However, getting the wheels off therunway is only part of the story. Youmust also clear an imaginary screen(usually 35 feet, but 50 for pistonaircraft) at the end of the TODA(TORA + Clearway). The distanceto do this is the Take-off DistanceRequired. If a single runway distanceis given, it must be used for bothTODA and TORA. The Take-off RunRequired (factored TODA) is 92% ofthe TODR.Part of the Clearway may be able tosupport an aircraft while stopping,although not under take-offconditions. This may be declared asStopway which may be added to theTORA to form the Emergency DistanceAvailable (EDA). This is the groundrun distance available for an aircraftto abort a take-off and come to restsafely—the essential point to note isthat Stopway is ground-based. EDAis sometimes also referred to as theEmergency Distance or Accelerate-StopDistance. The greater the EDA, thehigher the speed you can accelerateto before the point at which youmust decide to stop or go when anengine fails.Obviously, the TODR must not bemore than the TODA. If not alreadydone in the Flight Manual, theTODR must be factored by 1.33,after the corrections below havebeen multiplied together and applied(factoring means that the distancesare multiplied by those figures toprovide a safety margin).The Landing Distance Available mustsimilarly not be less than the LandingDistance Required. If there's a choiceof runways, the LDR is the greaterof that on the longest one in zerowind or on the runway used due toforecast winds. Don't forget theLDR is from 50 feet. Unless theFlight Manual states otherwise, theLDR must be factored by 1.43(giving 70% of distance available),again, after applying the followingcorrections.Airfield altitude and ambienttemperatureThe higher you are, the less densethe air and the less the ability of thewings (rotating or otherwise) andengines to "bite" into it, thusrequiring more power and longertake-off runs to get airborne.Humidity has a similar effect, but isusually allowed for in the graphs.TODR will increase by 10% for each1000-foot increase in aerodromealtitude and 10% per 10o C increasein temperature (factor by 1.1).LDR will increase by 5% for each1000-foot increase in pressurealtitude and 10o C increase intemperature (factor by 1.05).Aircraft weightGreater mass means sloweracceleration/deceleration and longerdistances. TODR will increase by20% for each 10% increase in weightand LDR 10% per 10% increase inweight (factor by 1.2 and 1.1). Veryfew aircraft allow you to fill all theseats with full fuel.140 Operational FlyingSome manuals give take-off andlanding weights that should not beexceeded at specific combinations ofaltitude and temperature, thusensuring that climb performance isnot compromised. These are knownas WAT limits (Weight, Altitude andTemperature), and are mandatory forCommercial Air Transport flights.Sometimes rates of climb are giveninstead, so you need to be aware thata Commercial Air Transportaeroplane must be able to maintain arate of climb of 700 fpm if it hasretractable landing gear, and 500 fpmotherwise. In a multi, if you can'tvisually avoid obstacles during climbor descent, you must be able toclimb at 150 fpm with one engine
out at the relevant altitudes andtemperatures (that's 500 feet in fivemiles!). This means all obstacles—you can't exclude frangible ones.Runway slopeGoing uphill when taking off willdelay acceleration and increase thedistance required. The converse istrue of downhill slopes and a rule ofthumb is that TODR will increase10% for each 2% of uphill slope,and vice versa (factor both by 1.1).When landing, an uphill slope aidsstopping, thereby reducing LDR.Any gains from landing upslope ortaking off downslope should not bemade use of but accepted as a bonus(that is, don't use them as part ofyour planning).Surface windsHeadwinds will reduce the distancesrequired and improve the flight pathafter take-off. Tailwinds have reverseeffects and crosswinds may evenexceed the ability of the tyres to gripthe runway. Aside from the handlingproblem, crosswinds may alsoincrease the TODR if you need touse the brakes to keep you straight.Forecast winds must be factored by50% for a headwind and 150% for atailwind—this may already beallowed for in the charts.TODR and LDR will increase by20% for each tailwind component of10% of the lift-off and landing speed(factor by 1.2).SurfacePerformance information is basedon a dry, hard surface. The runwaystate can affect directional andbraking ability, and has beendiscussed already. Meanwhile, fordry short grass (under 5”), theTODR will increase by 20%, afactor of 1.2. When it's wet, 25%—afactor of 1.25. For dry, long grass (5-10 inches), TODR will increase by25%, and 30% when wet (it's notrecommended that you operatewhen grass is over 10 inches high).For dry short grass (under 5 inches),the LDR will increase by 20%, afactor of 1.2. When it's wet, 30%—afactor of 1.3. For dry, long grass (5-10 inches), LDR will increase by30%, and 40% when wet. For othersoft ground or snow, the increasewill be in the order of 25% or morefor take-off and landing,ObstaclesTakeoff requirements also need toconsider obstacles further along thetake-off path which cannot beavoided visually. The area concernedis a funnel extending up to 1500 feetabove the airfield elevation from theend of the TODR within 75m eitherside of track (with all enginesoperating). The Net Flight Path isOperational Procedures 141made up of segments coveringvarious stages of flight (such aswhen undercarriage or flaps areraised) and is so called because NET(i.e. factored) performance data isused to assess it. The NFPcommences from 50’ above the endof the TODR, the imaginary screenthe aircraft must clear.If an obstacle (including a frangibleone) intrudes on the Net Flight Path,then take-off weight must bereduced until it's cleared by a marginof 35 (or whatever) feet, so this maybe a determining one in calculatingRestricted Takeoff Weight (see alsoLoading). You can make gentle turnsto avoid obstacles, and not have tofiddle with take-off weights, andthere will be graphs in the FlightManual allowing you to calculateradii and procedures for it. However,you will need to be visual as well, soa minimum cloudbase is necessary.If an engine fails in the climb out,normal practice would be to returnto the point of departure, but if youcan't (maybe the weather) the NFPand MSA must be examined at theflight planning stage. It may even benecessary to climb overhead to getthe height required before going foryour return alternate.You must use the one-engine inoperativenet flight path data from the point atwhich full instrument flyingcommences, or is expected to.Balked Approach Flight PathThis is similar to Net Flight Path,and commences at DH above theupwind end of the LDR. However,you may not be able to complete abalked landing or go around onceyou have entered a low-energylanding configuration, withouttouching the ground, because yourflaps and gear would be set forlanding, you would be below about50 feet, in descent, with the throttlein the idle range and with decreasingairspeed. Balked landings or go-aroundsshould be initiated before this point isreached – if you put your aircraft inthis state, the subsequent board ofinquiry would only assume youthought it was safe to do so. Asthere will be no performance figuresin the charts to cover it, this is a highrisk experiment – in fact, you arevery likely to stall if you climb beforeyour engines have spooled up.DiversionsYou must be capable of continuingthe flight from any point of enginefailure at or above MSA to 1500 feetabove a suitable airfield (withinWAT and runway limits), where youmust be able to maintain a positiverate of climb. Consideration musttherefore be given to height loss, andthe likely drift down rate withengine(s) out is established from theFlight Manual. The charts willindicate how quickly you can expectto descend, based on aircraft weight,temperature, altitude, etc.If the MOCA is quite high (say overthe Alps or the Rockies at 14,000feet), you're obviously going to bepushed to get there in some aircraftwith two engines, let alone one. Ifyou have to go that way and suspectyou may have performanceproblems, you could always workout your Drift Down with the helpof an emergency turn, informationabout which will also be found in theFlight Manual. What you do isestablish a point one side of whichperformance is OK and the otherside of which, if you have an engine142 Operational Flyingfailure, you make an emergency turn
to get yourself away from the areaand (hopefully) out of trouble.Again, the charts will indicate therate of descent in a turn and all youneed do then is ensure that yourMSA reduces at a greater rate thanyour altitude! If you can't complywith any of this, you may have toreduce your weight until you can.SpeedPeculiar to landing is speed—ahigher one than specified naturallyrequires a longer distance, not onlyfor slowing down, but the FAA havealso determined that being 5 knotstoo fast over the threshold is theequivalent of being 50 feet too high.Power SettingsThese are important. Noiseabatement sometimes meansreduced thrust on take-off, whichobviously tighten performancelimits, so will increase all yourdistances. EPR gauges should not beused by themselves as an indicationof engine power output, and shouldbe crossed referenced with otherinstruments, especially when there isa chance of the probes icing up. Therelevance of this becomes apparentwith an engine failure after V1, wheresome aircraft allow full throttlewithout exceeding performancelimits (like those with automaticcontrols). Others need the levers tobe set more accurately, and a likelyidea of what the limits will be beforetake-off. V1 is a fixed speed based onweight and flap settings (nothing todo with runway length), and issupposed to give you a safe full stopor a successful engine-out takeoff.However, high speed rejects areamong the top three causes ofaccidents. Unless you feel the aircraftwill be uncontrollable, your chancesmay better in the air.MiscellaneousLow tyre pressures increase distancesrequired.SummaryIt's obviously not a good plan tooperate to the limit of all the abovefactors all at once, as you would byarriving high and fast at a wet,downward sloping runway with atailwind!ChecklistsFunny things, these. You need them,but if you let passengers see youusing them, they wonder if youknow how to fly the aircraftproperly, though we all know thatthey are there to make sure you havedone everything, and are not actuallyinstructions. Psychologically, at least,it may be a good idea to use them asdiscreetly as possible. They areespecially important in companies,where different pilots leave switchesin strange positions, or when anaircraft comes out of servicing –using a checklist properly will ensurethat an aircraft is in a standardposition before any flight.Checklists should be available forevery crew member, and they willalso be fully listed in the OperationsManual. They should be used on allrelevant occasions, but on singlecrew flights, checks usually done inthe air may be completed frommemory, but is not recommended.
Memorised drills must be strictly inaccordance with Companychecklists, and emergency drills mustbe verified as soon as possible.Operational Procedures 143It may be helpful to have the vitalactions placarded somewhere—either on the back of a sun visor orprinted on the Nav Log.It's worth considering leaving thenavigation or anti-collision lights (orengine-out warnings) on when youleave an aircraft, despite what thechecklist says – then you know thatyou've left the Master switch on asyou walk away.Daily InspectionsEach day, before the first flight ofany aircraft, a Daily (Check A)Inspection is carried out. Althoughit's meant to be a specificmaintenance inspection, as laiddown in the Light Aircraft MaintenanceSchedule (LAMS), it's sort ofequivalent to a pilot's pre-flightinspection, which in turn isequivalent to the "externalwalkround" in the Flight Manual,only more detailed. The Check A issimilar to the status of the "FirstParade" given to every militaryvehicle at the start of each day, whenthe tyres and oil levels are checked.On smaller aircraft, it may be carriedout by a Commander with theapproval of the Chief Pilot, who willarrange for the necessary trainingwith the Company MaintenanceOrganisation. You will then beissued with a number to use againstyour signature on any paperwork. Inkeeping with General Aviationpractice, the Commanderperforming the first flight of the daynormally performs the Check A, andis responsible for signing the TechLog. You are responsible (asCommander) for checking it issigned by the person who did it.The term "Inspect" means that allitems are examined externally and insitu and that their condition when soinspected is so as to preservecontinued airworthiness.Throughout the Inspection, athorough examination should bemade of all surfaces and parts fordamage, corrosion, loose or missingrivets or bolts, distortion, cracking,dents, scores, chafing, kinking, leaks,excessive chipping of paintwork,overheating, fluid contamination andother signs of structural ormechanical damage. Parts shouldalso be checked for general securityand cleanliness and a particularinspection made of each drain andvent hole to ensure it is unblocked.Radio ProceduresA radio listening watch should bekept at all times as a matter ofairmanship, even though there arestill vast areas of the UK where youcan fly for hours without having totalk to anybody.There are one or two points, though,that aren't often taught properlyduring training. The first is to wait asplit second to speak after pressingthe transmit button, which gives allthe relays in the system a chance toswitch over so your message can getthrough in full, that is, not clippingthe first bit.Secondly, whenever you get afrequency change en route, not onlyshould you write it down on yourNav Log, but change to the newfrequency on the other box, so youalternate between radios. This way,you have something to go back to ifyou can't get through on the newone for whatever reason (although itis appreciated that this could create144 Operational Flyingdifficulties with two station boxesand you have to switch them bothevery time). Also, use the switcheson the station box to silence radios,not the volume controls, otherwiseyou get endless embarrassingsituations where you transmit, get noreply, wonder what-in-hell-ishappening and suddenly realiseyou've turned the volume down andhave been blocking everybody elseout. That's when the Standard AirTraffic Voice tells you he's beencalling you for the past 5 minutes......TranspondersThe code your flight will use isallocated when the computer spits itout to the appropriate sectorcontroller before you get airborne.Together with the callsign, it’s alsopassed to the Callsign DistributionSystem for display on the radarscreens of the relevant ATC units,after which the flight is activatedautomatically by the radar, in thecase of London or Manchester,about a minute after takeoff.Reliability here is entirely dependenton you squawking the correct code,
or another flight could be activated.Radio failureEssentially, comply with the lastclearance, which hopefully includedpermission to land or clear the area.If you don’t need to enter controlledairspace, carry on with the plan,maintaining VFR as necessary; don'tenter it even if you’ve beenpreviously cleared. If you must doso, divert and telephone forpermission first. If you’re already incontrolled airspace, where clearancehas been obtained to the boundaryon leaving, or the field on entering,proceed as planned. If in doubt,clear the zone as directly and quicklyas possible, avoiding airfields.The military have a system of flyinga left or right-handed triangle patternthat can be seen on radar, althoughit's usually only used if you're lost aswell as having a duff radio. Use it asa last resort, though, because ATChave other things to look out forthan possible triangles. If they dorecognise your problem, they willsend up a shepherd aircraft toformate on you and bring you down,so remain VMC if you can, and ashigh as possible so radar can see youbetter. If you can squawk Mode C,do so, because that will give a heightreadout to work with.If you can only receive messages, flyin a right handed pattern for aminute (if your airspeed is over 300knots, make it two). Fly at bestendurance speed and make each 120degree turn as tight as possible. Ifyou can't transmit either, do thesame, but to the left.RT Emergency ProceduresYou should always declare anEmergency, even if you have todowngrade it later.The Distress call (or "MAYDAY") isused when the aircraft is threatenedby imminent danger and is in mosturgent need of immediate assistance.If and when the threat of danger hasbeen overcome, the Distress callmust be cancelled by notification onALL frequencies on which theoriginal message was sent.The Urgency call (or "PAN")indicates that the aircraft has a veryurgent message to transmitconcerning the safety of a ship,Operational Procedures 145aircraft or other vehicle, or of someperson on board or in sight.Flights Over WaterExcept with permission from theCAA, no flight may exceed 3minutes continuously over water, forwhich float gear must be fitted andserviceable (in a helicopter), and lifejackets worn. For over 3 minutes,aircraft must be equipped as perSchedule 4.HelicoptersAny flight beyond autorotativedistance from land (20 seconds) is anoverwater flight. For any such flight,or when flying along the Thames inthe London Control Zone, betweenHammersmith Bridge and ChelseaReach, approved lifejackets for eachperson on board should be carried,as well as flotation gear.For flights more than 3 minutes overwater, the following conditionsshould apply:·
A dinghy and SARBE (SearchAnd Rescue Beacon) must becarried.·
No night flying (single-enginedonly).·
Two way radio communicationmust be maintained withposition reporting every tenminutes.·
Flight plan to be filed.·
SAR to be notified.·
Immersion suits to be wornwhen practical.·
A serviceable radio altimeterwith voice must be fitted.·
Passengers must be given a fullbriefing on all emergencyequipment.AeroplanesIn an aeroplane, when over water formore than 90 minutes' flying time atthe recommended over water speed,an approved lifejacket for eachperson on board must be carried aswell as enough liferafts for everyone.If over 30 minutes, a demonstrationmust be given.Also, when beyond gliding distancefrom shore, the lifejackets need to becarried whenever it is reasonablypossible that a landing may have tobe made on water during take-off orlanding, to cover for coastal airfields.If you're in a single-engined aircraft,and going beyond gliding distancefrom shore, make the passengerswear their lifejackets from the start,and ensure they know how to use
them. In a twin, it's enough just topoint out their location and theinstructions on the briefing card.However, if one of the enginesstops, you become single-engined, soget your passengers to don themimmediately.Except due to the nature of the task,overwater routings should not beplanned if alternative overlandroutes are available. No unplannedoverwater flight may be conductedexcept in emergency. In any case,overwater time should be minimised.Life RaftOn any flight planned to coast outfrom the mainland or cross a tract ofwater more than 3 minutes flyingtime wide, a life raft must be carried,which must carry all occupants andbe properly restrained so it's ready146 Operational Flyingfor use. Life rafts must be equippedwith carbon dioxide inflation bottlesand a secondary means of inflation,as well as having adequate protectionfor the occupants, bailing apparatus,leak stoppers, a maritime survivalpack and a water activated light.FlaresOn any flight carrying a life raft, thecommander must have either aday/night distress flare or a miniflaregun and cartridges, which may becarried as part of the life raftequipment.Personal Locator BeaconOn all flights carrying a liferaft thecommander must have anEmergency Locator Beacondesigned to transmit on 121.5 MHzand 243.00 MHz.Immersion SuitsTo be worn by all on board on alloverwater flights with a watertemperature is at or below 10o C.Sea StateOverwater flights must not takeplace where forecast wave heightexceeds 6 feet.Weather Minima600 feet cloud base and horizontalvisibility of 6000 metres. Minimumwind 5 kts.power pedal in a fast turn the otherway will create a torque spike.DitchingDitching is a deliberate act, ratherthan an uncontrolled impact,although the terms are often usedsynonymously. A successful onedepends on sea conditions, wind,type of aircraft and your skill, but it'sthe after effects, like survival andrescue that appear to cause theproblems (88% of controlledditchings happen without too manyinjuries, but over 50% of survivorsdie before help arrives).Of course, the best way out of aditching is not to get into one, butyou can't always avoid flying overwater. The next best thing is toprepare as much as possiblebeforehand, and make sure that theequipment you need is readilyavailable, and not stuck in thebaggage compartment where no-onecan reach it. Have you really gotenough fuel for the trip? Did youtop up the oil or check the weather?Once under way, flying higher helps
in two ways, by giving you that littleextra time to reach land, and to allowyou to brief and prepare thepassengers better. Maintaining aconstant listening watch helpssomebody know your position, asdoes filing a flight plan before going.Sea MovementIt's a good idea to have a basicknowledge, as getting the headingright may well mean the differencebetween survival and disaster.Whereas waves arise from localwinds, swells (which relate to largerbodies of water), rely on moredistant and substantial disturbances.They move primarily up and down,and only give the illusion ofmovement, as the sea does notactually move much horizontally.This is more dominant than anythingcaused by the wind, so it doesn'tdepend on wind direction, althoughsecondary swells may well do. It'sextremely dangerous to land intoOperational Procedures 147wind without regard to seaconditions; the swell must be takeninto consideration, although it couldassume less importance if the wind isvery strong.The vast majority of swells are lowerthan 12-15 feet, and the swell face isthe side facing you, whereas thebackside is away from you. Thisseems to apply regardless of thedirection of swell movement.The ProcedureYou will need to transmit all yourMAYDAY calls and squawks (7700)while still airborne, as well as turningon your ELT, or SARBE. If timepermits, warn the passengers to dontheir lifejackets (without inflatingthem, or the liferafts) and tightenseat belts, remove any headsets, stowany loose items (dentures, etc.) andpair off for mutual support, beingready to operate any emergencyequipment that may be to hand (theyshould have been briefed on thisbefore departure).One passenger should be the"dinghy monitor", that is, beresponsible for the liferaft. If it'sdark, turn on the cabin lights andensure everyone braces beforeimpact (the brace position helps toreduce the flailing of limbs, etc. asyou hit the water, although itsprimary purpose is to stop peoplesliding underneath the lap strap;there are different ones for forwardand aft seats).If only one swell system exists, theproblem is relatively simple—even ifit's a high, fast one. Unfortunately,most cases involve two or moresystems running in differentdirections, giving the sea a confusedappearance. Always land either onthe top, or on the backside of a swellin a trough (after the passage of acrest) as near as possible to anyshipping, meaning you neither getthe water suddenly falling away fromyou nor get swamped with water,and help is near.Although you should normally landparallel to the primary swell, if thewind is strong, consider landingacross if it helps minimisegroundspeed (although in most casesdrift caused by crosswind can beignored, being only a secondaryconsideration to the forces contactedon touch-down). Thus, with a bigswell, you should accept morecrosswind to avoid landing directlyinto it. The simplest way ofestimating the wind is to examinethe wind streaks on the water whichappear as long white streaks up- anddownwind. Whichever way the foamappears to be sliding backwards isthe wind direction (in other words,it's the opposite of what you think),and the relative speed is determinedfrom the activity of the streaksthemselves. Shadows and whitecapsare signs of large seas, and if they'reclose together, the sea will be shortand rough. Avoid these areas as faras possible—you only need about500' or so to play with.The behaviour of the aircraft onmaking contact with the water willvary according to the state of the sea;the more confused and heavy theswell, the greater the decelerationforces and risks of breaking up(helicopters with a high C of G, suchas the Puma, will tip over very easily,and need a sea anchor to keep themstable – in fact, the chances of anyhelicopter turning upside down arequite high). Landing is less148 Operational Flyinghazardous in a helicopter becauseyou can minimise forward speed. Infact, if you are intentionally ditching,you should come to a hover abovethe water first, then throw out the kit
