飞行员操作飞行手册Pilot Operational Flying Manual

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000 feet PA, but maintaining cabin

pressure altitudes below that.

Flight Crew

Each member of the flight crew shall

have:

Operational Procedures 135

· an oxygen mask within

immediate reach, which may be

the same one as above,

excluding the portable

apparatus. When above 25 000

feet, the mask must be a quick

donning type.

· when cabin pressure fails,

oxygen for the time the cabin

altitude exceeds 10 000 feet,

with a minimum of 30 minutes

for aircraft below 25 000', and 2

hours for those above.

· essential flight crew members

must use oxygen continuously

after 30 minutes at a cabin PA

over 10 000 feet, and at all times

over

highest skills from crews and placing

the most strain on the aircraft.

Because of this, strict regulations

govern the information used for

calculating take-off or landing

performance. Of course, in the old

days (say during the war, or when

the trains ran on time), having

enough engines to lift the load was

136 Operational Flying

all that mattered and no priority was

given to reserves of power and the

like. Now it's different, and

performance requirements will be

worked out before a C of A is

issued, over a wide range of

conditions. They are subsequently

incorporated in the Flight Manual,

which actually forms part of the C of

A. In addition, the ANO requires

you to ensure that your aircraft has

adequate performance for any

proposed flight.

Aircraft are certified in one of

several groups (A, A (Restricted), or

B for helicopters, or A B C D E or F

for aeroplanes); the higher the

performance of the aircraft, the

lower the alphabetical letter (a 737

comes under Performance A, for

instance, while anything up to 9 seats

that may require a forced landing

after engine failure will come under

F). Well, at least, that’s how the

ANO works. JAR does it differently

as we have already seen.

The group in which an aircraft

operates depends on its

Certification, Max All-Up Weight

and the number of passengers it

carries. Within these limits you can

choose which group to operate in,

and come under the appropriate

weather and weight limitations; it

may be more acceptable

commercially, for example, to

operate in a lesser group if it enables

you to take more payload, and make

more money – all you might need is

longer runways.

Individual aircraft of a given species

will vary in performance due to such

variables as the age of the airframe

and engines, the standard of

maintenance, or the skill and

experience of the crews. What you

can do on one day under a given set

of circumstances may well be

impossible another time. The

original testing, of course, is done

with new aircraft and highly

experienced pilots. These results are

unfactored, and not all performance

data for foreign aircraft is actually

verified by the CAA, though they do

carry out spot checks. In fact, any

figures are a mixture of actual

readings and calculated (or

guesstimated) adjustments from

them. The "performance" of an

aircraft is therefore a set of average

values—particular machines may be

better or worse.

There are fudge factors applied to

unfactored figures to produce net

performance (and gross performance when

they're not). Occasionally,

performance data (as amended by

the CAA) in a flight manual will

already be factored, but you will

have to check the small print on the

chart, in case they surprise you.

Figures and graphs are based on

Standard conditions which allow for

fixed reductions in pressure and

temperature with height. As we all

know, the real world isn't like that,

so these assumptions may not always

be true and due allowance must

therefore be made for them (if your

aircraft is performing sluggishly, you

may find it's not the machine, but

the conditions it has to work under

that are at fault).

Performance A aircraft must (with

one engine out) clear all obstacles

under the departure track within a

defined area by a specified margin,

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without relying on seeing and

avoiding them – in Canada, for

example, aircraft are expected to

climb at over 200 feet per nm from a

Operational Procedures 137

point 35 feet above the end of the

runway, because obstacles are

assessed inside a slope of 152 feet

per nm, which gives you a clearance

of 48 feet (if there are no obstacles,

the takeoff visibility can also be

lower). All the relevant data will be

in the graphs, but some groups have

no information at all in some areas.

For instance, an aircraft in

Performance Group C is assumed to

have all engines working until above

200 feet, under which height there is

no data for landing or take-off

(which is why the take-off minima

will rarely be below this, because you

must be visual to avoid any obstacles

should an engine fail). Sometimes,

there can be no specific provision

for engine failure at all.

Each group requires certain

conditions to be met, either in

standards of power available,

environment or special procedures.

For example, take-off, landing and

reject areas need to be prepared

surfaces for Class A helicopters,

which also have to achieve certain

net gradients at particular points in

the climb. Lower groups are more

relaxed, but still have limitations—

you need somewhere to land in

emergency, but for these you only

need to avoid risk to third parties

while meeting certain weather limits.

Keeping to the helicopter theme,

Class A (1) take-off procedures

involve a vertical and backwards

liftoff to a predetermined height

before going forward, which is

known as the Critical Decision Point

(or CDP), and gives you a choice of

action if an emergency happens

(actually, ICAO now call it the

Takeoff Decision Point, or TDP).

Having moved backwards, you still

have the take-off spot in sight and

it's therefore available for landing. At

CDP (or TDP), if you elect to carry

on to forward flight, you should be

able to clear the landing spot during

the steep dive you have to make to

achieve flying speed (that's why the

CDP is about 40 feet high). Things

happen in reverse on landing. This

procedure is not without its critics,

since prolonged hovering at high

engine power outputs is not good

engine handling.

Anyhow, whatever you're flying, you

will find the data needed to check

your performance in the Flight

Manual, which will have a UK

supplement if your aircraft is foreign

made—these override any

information in the standard manuals.

General principles concerning

distances for take-off and landing are

similar for aeroplanes and

helicopters; for example, take-off

distances for both will increase by

10% for each 1000-foot increase in

Pressure Altitude.

Some factors affecting performance

include:

Density Altitude

This is is the altitude at which the

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ISA density is the same as that of the

air in question or, in other words,

your real altitude resulting from the

effects of height, temperature,

pressure and humidity, all of which

can make the air thinner and which

are mentioned below. The details

will be in the Flight Manual,

although humidity is usually ignored

in the average performance chart,

because it has more to do with

engine power than aerodynamic

efficiency, and high air density and

humidity do not often go hand in

138 Operational Flying

hand. However, if the air is humid,

say after a good shower, you would

be wise to be careful.

Anyhow, the idea is that the more

the density of the air decreases for

any reason, the higher your aircraft

thinks it is. If you look at the lift

formula, you will see that the lift

from a wing or thrust from a

propeller is directly dependent on air

density, as is drag, of course. The

effects are as valid at sea level as they

are in mountainous areas when

temperatures are high – for example,

90° (F) at sea level is really 1900' as

far as your machine is concerned. In

extreme circumstances, you may

have to restrict your operations to

early morning or late afternoon.

Here is a handy chart:

°F/C 60/15.6 70/21.1 80/26.7

1,000’ 1300 2000 2700

2000’ 2350 3100 3800

3000’ 3600 4300 5000

4000’ 4650 5600 6300

5000’ 6350 6900 7600

6000’ 7400 8100 8800

7000’ 8600 9300 1,0000

8000’ 9700 10400 11100

9000’ 11,000 11600 12400

1,0000’ 12250 13000 13600

11,000’ 13600 14300 15000

12000’ 14750 15400 16000

It shows that, at 6,000 feet and 21°C,

for example, you should enter

performance charts at 8100 feet.

If you want to work it out for

yourself, try this formula:

DA = 145,366[1 - (X

0.235

)]

where X is the station pressure in

inches divided by the temperature in

Rankin degrees, which are found by

adding 459.69 to Fahrenheit totals.

Altitude

Air density drops off by .002 lbs per

cubic foot (i.e. 2½ %) for every

1000 feet in the lower layers of the

atmosphere.

Humidity

Adding water vapour to air makes it

less dense because the molecular

weight is lower (dry air is 29 –water

vapour is 18). On cold days,

humidity is less of a problem simply

because cold air holds less vapour. A

relative humidity of 90% at 70°F

means twice as much than at 50°F.

Temperature

As heat expands air, it becomes

thinner. Thinner air is less dense

(Boyles Law). On the surface, an

increase in temperature will decrease

density and increase volume, with

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pressure remaining constant. At

altitude, however, pressure reduces

more than temperature does, and

will produce an apparent

contradiction, where temperature

will decrease from the expansion.

Pressure

Air density reduces with atmospheric

pressure (Charles Law). When you

compress air, its density increases.

Runway length

Details are declared by the Airport

Authority and published in the AIP.

This declared distance is either the

Take-off Run Available (TORA) or

Landing Distance Available (LDA).

Any areas at the ends unsuitable to

run on, but nevertheless clear of

obstacles, are called Clearways, which,

with the TORA, form the Take-off

Operational Procedures 139

Distance Available (TODA), which

should not be more than 1½ x

TORA.

However, getting the wheels off the

runway is only part of the story. You

must also clear an imaginary screen

(usually 35 feet, but 50 for piston

aircraft) at the end of the TODA

(TORA + Clearway). The distance

to do this is the Take-off Distance

Required. If a single runway distance

is given, it must be used for both

TODA and TORA. The Take-off Run

Required (factored TODA) is 92% of

the TODR.

Part of the Clearway may be able to

support an aircraft while stopping,

although not under take-off

conditions. This may be declared as

Stopway which may be added to the

TORA to form the Emergency Distance

Available (EDA). This is the ground

run distance available for an aircraft

to abort a take-off and come to rest

safely—the essential point to note is

that Stopway is ground-based. EDA

is sometimes also referred to as the

Emergency Distance or Accelerate-Stop

Distance. The greater the EDA, the

higher the speed you can accelerate

to before the point at which you

must decide to stop or go when an

engine fails.

Obviously, the TODR must not be

more than the TODA. If not already

done in the Flight Manual, the

TODR must be factored by 1.33,

after the corrections below have

been multiplied together and applied

(factoring means that the distances

are multiplied by those figures to

provide a safety margin).

The Landing Distance Available must

similarly not be less than the Landing

Distance Required. If there's a choice

of runways, the LDR is the greater

of that on the longest one in zero

wind or on the runway used due to

forecast winds. Don't forget the

LDR is from 50 feet. Unless the

Flight Manual states otherwise, the

LDR must be factored by 1.43

(giving 70% of distance available),

again, after applying the following

corrections.

Airfield altitude and ambient

temperature

The higher you are, the less dense

the air and the less the ability of the

wings (rotating or otherwise) and

engines to "bite" into it, thus

requiring more power and longer

take-off runs to get airborne.

Humidity has a similar effect, but is

usually allowed for in the graphs.

TODR will increase by 10% for each

1000-foot increase in aerodrome

altitude and 10% per 10o C increase

in temperature (factor by 1.1).

LDR will increase by 5% for each

1000-foot increase in pressure

altitude and 10o C increase in

temperature (factor by 1.05).

Aircraft weight

Greater mass means slower

acceleration/deceleration and longer

distances. TODR will increase by

20% for each 10% increase in weight

and LDR 10% per 10% increase in

weight (factor by 1.2 and 1.1). Very

few aircraft allow you to fill all the

seats with full fuel.

140 Operational Flying

Some manuals give take-off and

landing weights that should not be

exceeded at specific combinations of

altitude and temperature, thus

ensuring that climb performance is

not compromised. These are known

as WAT limits (Weight, Altitude and

Temperature), and are mandatory for

Commercial Air Transport flights.

Sometimes rates of climb are given

instead, so you need to be aware that

a Commercial Air Transport

aeroplane must be able to maintain a

rate of climb of 700 fpm if it has

retractable landing gear, and 500 fpm

otherwise. In a multi, if you can't

visually avoid obstacles during climb

or descent, you must be able to

climb at 150 fpm with one engine

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out at the relevant altitudes and

temperatures (that's 500 feet in five

miles!). This means all obstacles—

you can't exclude frangible ones.

Runway slope

Going uphill when taking off will

delay acceleration and increase the

distance required. The converse is

true of downhill slopes and a rule of

thumb is that TODR will increase

10% for each 2% of uphill slope,

and vice versa (factor both by 1.1).

When landing, an uphill slope aids

stopping, thereby reducing LDR.

Any gains from landing upslope or

taking off downslope should not be

made use of but accepted as a bonus

(that is, don't use them as part of

your planning).

Surface winds

Headwinds will reduce the distances

required and improve the flight path

after take-off. Tailwinds have reverse

effects and crosswinds may even

exceed the ability of the tyres to grip

the runway. Aside from the handling

problem, crosswinds may also

increase the TODR if you need to

use the brakes to keep you straight.

Forecast winds must be factored by

50% for a headwind and 150% for a

tailwind—this may already be

allowed for in the charts.

TODR and LDR will increase by

20% for each tailwind component of

10% of the lift-off and landing speed

(factor by 1.2).

Surface

Performance information is based

on a dry, hard surface. The runway

state can affect directional and

braking ability, and has been

discussed already. Meanwhile, for

dry short grass (under 5”), the

TODR will increase by 20%, a

factor of 1.2. When it's wet, 25%—a

factor of 1.25. For dry, long grass (5-

10 inches), TODR will increase by

25%, and 30% when wet (it's not

recommended that you operate

when grass is over 10 inches high).

For dry short grass (under 5 inches),

the LDR will increase by 20%, a

factor of 1.2. When it's wet, 30%—a

factor of 1.3. For dry, long grass (5-

10 inches), LDR will increase by

30%, and 40% when wet. For other

soft ground or snow, the increase

will be in the order of 25% or more

for take-off and landing,

Obstacles

Takeoff requirements also need to

consider obstacles further along the

take-off path which cannot be

avoided visually. The area concerned

is a funnel extending up to 1500 feet

above the airfield elevation from the

end of the TODR within 75m either

side of track (with all engines

operating). The Net Flight Path is

Operational Procedures 141

made up of segments covering

various stages of flight (such as

when undercarriage or flaps are

raised) and is so called because NET

(i.e. factored) performance data is

used to assess it. The NFP

commences from 50’ above the end

of the TODR, the imaginary screen

the aircraft must clear.

If an obstacle (including a frangible

one) intrudes on the Net Flight Path,

then take-off weight must be

reduced until it's cleared by a margin

of 35 (or whatever) feet, so this may

be a determining one in calculating

Restricted Takeoff Weight (see also

Loading). You can make gentle turns

to avoid obstacles, and not have to

fiddle with take-off weights, and

there will be graphs in the Flight

Manual allowing you to calculate

radii and procedures for it. However,

you will need to be visual as well, so

a minimum cloudbase is necessary.

If an engine fails in the climb out,

normal practice would be to return

to the point of departure, but if you

can't (maybe the weather) the NFP

and MSA must be examined at the

flight planning stage. It may even be

necessary to climb overhead to get

the height required before going for

your return alternate.

You must use the one-engine inoperative

net flight path data from the point at

which full instrument flying

commences, or is expected to.

Balked Approach Flight Path

This is similar to Net Flight Path,

and commences at DH above the

upwind end of the LDR. However,

you may not be able to complete a

balked landing or go around once

you have entered a low-energy

landing configuration, without

touching the ground, because your

flaps and gear would be set for

landing, you would be below about

50 feet, in descent, with the throttle

in the idle range and with decreasing

airspeed. Balked landings or go-arounds

should be initiated before this point is

reached – if you put your aircraft in

this state, the subsequent board of

inquiry would only assume you

thought it was safe to do so. As

there will be no performance figures

in the charts to cover it, this is a high

risk experiment – in fact, you are

very likely to stall if you climb before

your engines have spooled up.

Diversions

You must be capable of continuing

the flight from any point of engine

failure at or above MSA to 1500 feet

above a suitable airfield (within

WAT and runway limits), where you

must be able to maintain a positive

rate of climb. Consideration must

therefore be given to height loss, and

the likely drift down rate with

engine(s) out is established from the

Flight Manual. The charts will

indicate how quickly you can expect

to descend, based on aircraft weight,

temperature, altitude, etc.

If the MOCA is quite high (say over

the Alps or the Rockies at 14,000

feet), you're obviously going to be

pushed to get there in some aircraft

with two engines, let alone one. If

you have to go that way and suspect

you may have performance

problems, you could always work

out your Drift Down with the help

of an emergency turn, information

about which will also be found in the

Flight Manual. What you do is

establish a point one side of which

performance is OK and the other

side of which, if you have an engine

142 Operational Flying

failure, you make an emergency turn

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to get yourself away from the area

and (hopefully) out of trouble.

Again, the charts will indicate the

rate of descent in a turn and all you

need do then is ensure that your

MSA reduces at a greater rate than

your altitude! If you can't comply

with any of this, you may have to

reduce your weight until you can.

Speed

Peculiar to landing is speed—a

higher one than specified naturally

requires a longer distance, not only

for slowing down, but the FAA have

also determined that being 5 knots

too fast over the threshold is the

equivalent of being 50 feet too high.

Power Settings

These are important. Noise

abatement sometimes means

reduced thrust on take-off, which

obviously tighten performance

limits, so will increase all your

distances. EPR gauges should not be

used by themselves as an indication

of engine power output, and should

be crossed referenced with other

instruments, especially when there is

a chance of the probes icing up. The

relevance of this becomes apparent

with an engine failure after V1, where

some aircraft allow full throttle

without exceeding performance

limits (like those with automatic

controls). Others need the levers to

be set more accurately, and a likely

idea of what the limits will be before

take-off. V1 is a fixed speed based on

weight and flap settings (nothing to

do with runway length), and is

supposed to give you a safe full stop

or a successful engine-out takeoff.

However, high speed rejects are

among the top three causes of

accidents. Unless you feel the aircraft

will be uncontrollable, your chances

may better in the air.

Miscellaneous

Low tyre pressures increase distances

required.

Summary

It's obviously not a good plan to

operate to the limit of all the above

factors all at once, as you would by

arriving high and fast at a wet,

downward sloping runway with a

tailwind!

Checklists

Funny things, these. You need them,

but if you let passengers see you

using them, they wonder if you

know how to fly the aircraft

properly, though we all know that

they are there to make sure you have

done everything, and are not actually

instructions. Psychologically, at least,

it may be a good idea to use them as

discreetly as possible. They are

especially important in companies,

where different pilots leave switches

in strange positions, or when an

aircraft comes out of servicing –

using a checklist properly will ensure

that an aircraft is in a standard

position before any flight.

Checklists should be available for

every crew member, and they will

also be fully listed in the Operations

Manual. They should be used on all

relevant occasions, but on singlecrew flights, checks usually done in

the air may be completed from

memory, but is not recommended.

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Memorised drills must be strictly in

accordance with Company

checklists, and emergency drills must

be verified as soon as possible.

Operational Procedures 143

It may be helpful to have the vital

actions placarded somewhere—

either on the back of a sun visor or

printed on the Nav Log.

It's worth considering leaving the

navigation or anti-collision lights (or

engine-out warnings) on when you

leave an aircraft, despite what the

checklist says – then you know that

you've left the Master switch on as

you walk away.

Daily Inspections

Each day, before the first flight of

any aircraft, a Daily (Check A)

Inspection is carried out. Although

it's meant to be a specific

maintenance inspection, as laid

down in the Light Aircraft Maintenance

Schedule (LAMS), it's sort of

equivalent to a pilot's pre-flight

inspection, which in turn is

equivalent to the "external

walkround" in the Flight Manual,

only more detailed. The Check A is

similar to the status of the "First

Parade" given to every military

vehicle at the start of each day, when

the tyres and oil levels are checked.

On smaller aircraft, it may be carried

out by a Commander with the

approval of the Chief Pilot, who will

arrange for the necessary training

with the Company Maintenance

Organisation. You will then be

issued with a number to use against

your signature on any paperwork. In

keeping with General Aviation

practice, the Commander

performing the first flight of the day

normally performs the Check A, and

is responsible for signing the Tech

Log. You are responsible (as

Commander) for checking it is

signed by the person who did it.

The term "Inspect" means that all

items are examined externally and in

situ and that their condition when so

inspected is so as to preserve

continued airworthiness.

Throughout the Inspection, a

thorough examination should be

made of all surfaces and parts for

damage, corrosion, loose or missing

rivets or bolts, distortion, cracking,

dents, scores, chafing, kinking, leaks,

excessive chipping of paintwork,

overheating, fluid contamination and

other signs of structural or

mechanical damage. Parts should

also be checked for general security

and cleanliness and a particular

inspection made of each drain and

vent hole to ensure it is unblocked.

Radio Procedures

A radio listening watch should be

kept at all times as a matter of

airmanship, even though there are

still vast areas of the UK where you

can fly for hours without having to

talk to anybody.

There are one or two points, though,

that aren't often taught properly

during training. The first is to wait a

split second to speak after pressing

the transmit button, which gives all

the relays in the system a chance to

switch over so your message can get

through in full, that is, not clipping

the first bit.

Secondly, whenever you get a

frequency change en route, not only

should you write it down on your

Nav Log, but change to the new

frequency on the other box, so you

alternate between radios. This way,

you have something to go back to if

you can't get through on the new

one for whatever reason (although it

is appreciated that this could create

144 Operational Flying

difficulties with two station boxes

and you have to switch them both

every time). Also, use the switches

on the station box to silence radios,

not the volume controls, otherwise

you get endless embarrassing

situations where you transmit, get no

reply, wonder what-in-hell-ishappening and suddenly realise

you've turned the volume down and

have been blocking everybody else

out. That's when the Standard Air

Traffic Voice tells you he's been

calling you for the past 5 minutes......

Transponders

The code your flight will use is

allocated when the computer spits it

out to the appropriate sector

controller before you get airborne.

Together with the callsign, it’s also

passed to the Callsign Distribution

System for display on the radar

screens of the relevant ATC units,

after which the flight is activated

automatically by the radar, in the

case of London or Manchester,

about a minute after takeoff.

Reliability here is entirely dependent

on you squawking the correct code,

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or another flight could be activated.

Radio failure

Essentially, comply with the last

clearance, which hopefully included

permission to land or clear the area.

If you don’t need to enter controlled

airspace, carry on with the plan,

maintaining VFR as necessary; don't

enter it even if you’ve been

previously cleared. If you must do

so, divert and telephone for

permission first. If you’re already in

controlled airspace, where clearance

has been obtained to the boundary

on leaving, or the field on entering,

proceed as planned. If in doubt,

clear the zone as directly and quickly

as possible, avoiding airfields.

The military have a system of flying

a left or right-handed triangle pattern

that can be seen on radar, although

it's usually only used if you're lost as

well as having a duff radio. Use it as

a last resort, though, because ATC

have other things to look out for

than possible triangles. If they do

recognise your problem, they will

send up a shepherd aircraft to

formate on you and bring you down,

so remain VMC if you can, and as

high as possible so radar can see you

better. If you can squawk Mode C,

do so, because that will give a height

readout to work with.

If you can only receive messages, fly

in a right handed pattern for a

minute (if your airspeed is over 300

knots, make it two). Fly at best

endurance speed and make each 120

degree turn as tight as possible. If

you can't transmit either, do the

same, but to the left.

RT Emergency Procedures

You should always declare an

Emergency, even if you have to

downgrade it later.

The Distress call (or "MAYDAY") is

used when the aircraft is threatened

by imminent danger and is in most

urgent need of immediate assistance.

If and when the threat of danger has

been overcome, the Distress call

must be cancelled by notification on

ALL frequencies on which the

original message was sent.

The Urgency call (or "PAN")

indicates that the aircraft has a very

urgent message to transmit

concerning the safety of a ship,

Operational Procedures 145

aircraft or other vehicle, or of some

person on board or in sight.

Flights Over Water

Except with permission from the

CAA, no flight may exceed 3

minutes continuously over water, for

which float gear must be fitted and

serviceable (in a helicopter), and life

jackets worn. For over 3 minutes,

aircraft must be equipped as per

Schedule 4.

Helicopters

Any flight beyond autorotative

distance from land (20 seconds) is an

overwater flight. For any such flight,

or when flying along the Thames in

the London Control Zone, between

Hammersmith Bridge and Chelsea

Reach, approved lifejackets for each

person on board should be carried,

as well as flotation gear.

For flights more than 3 minutes over

water, the following conditions

should apply:

· A dinghy and SARBE (Search

And Rescue Beacon) must be

carried.

· No night flying (single-engined

only).

· Two way radio communication

must be maintained with

position reporting every ten

minutes.

· Flight plan to be filed.

· SAR to be notified.

· Immersion suits to be worn

when practical.

· A serviceable radio altimeter

with voice must be fitted.

· Passengers must be given a full

briefing on all emergency

equipment.

Aeroplanes

In an aeroplane, when over water for

more than 90 minutes' flying time at

the recommended over water speed,

an approved lifejacket for each

person on board must be carried as

well as enough liferafts for everyone.

If over 30 minutes, a demonstration

must be given.

Also, when beyond gliding distance

from shore, the lifejackets need to be

carried whenever it is reasonably

possible that a landing may have to

be made on water during take-off or

landing, to cover for coastal airfields.

If you're in a single-engined aircraft,

and going beyond gliding distance

from shore, make the passengers

wear their lifejackets from the start,

and ensure they know how to use

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them. In a twin, it's enough just to

point out their location and the

instructions on the briefing card.

However, if one of the engines

stops, you become single-engined, so

get your passengers to don them

immediately.

Except due to the nature of the task,

overwater routings should not be

planned if alternative overland

routes are available. No unplanned

overwater flight may be conducted

except in emergency. In any case,

overwater time should be minimised.

Life Raft

On any flight planned to coast out

from the mainland or cross a tract of

water more than 3 minutes flying

time wide, a life raft must be carried,

which must carry all occupants and

be properly restrained so it's ready

146 Operational Flying

for use. Life rafts must be equipped

with carbon dioxide inflation bottles

and a secondary means of inflation,

as well as having adequate protection

for the occupants, bailing apparatus,

leak stoppers, a maritime survival

pack and a water activated light.

Flares

On any flight carrying a life raft, the

commander must have either a

day/night distress flare or a miniflare

gun and cartridges, which may be

carried as part of the life raft

equipment.

Personal Locator Beacon

On all flights carrying a liferaft the

commander must have an

Emergency Locator Beacon

designed to transmit on 121.5 MHz

and 243.00 MHz.

Immersion Suits

To be worn by all on board on all

overwater flights with a water

temperature is at or below 10o C.

Sea State

Overwater flights must not take

place where forecast wave height

exceeds 6 feet.

Weather Minima

600 feet cloud base and horizontal

visibility of 6000 metres. Minimum

wind 5 kts.

power pedal in a fast turn the other

way will create a torque spike.

Ditching

Ditching is a deliberate act, rather

than an uncontrolled impact,

although the terms are often used

synonymously. A successful one

depends on sea conditions, wind,

type of aircraft and your skill, but it's

the after effects, like survival and

rescue that appear to cause the

problems (88% of controlled

ditchings happen without too many

injuries, but over 50% of survivors

die before help arrives).

Of course, the best way out of a

ditching is not to get into one, but

you can't always avoid flying over

water. The next best thing is to

prepare as much as possible

beforehand, and make sure that the

equipment you need is readily

available, and not stuck in the

baggage compartment where no-one

can reach it. Have you really got

enough fuel for the trip? Did you

top up the oil or check the weather?

Once under way, flying higher helps

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in two ways, by giving you that little

extra time to reach land, and to allow

you to brief and prepare the

passengers better. Maintaining a

constant listening watch helps

somebody know your position, as

does filing a flight plan before going.

Sea Movement

It's a good idea to have a basic

knowledge, as getting the heading

right may well mean the difference

between survival and disaster.

Whereas waves arise from local

winds, swells (which relate to larger

bodies of water), rely on more

distant and substantial disturbances.

They move primarily up and down,

and only give the illusion of

movement, as the sea does not

actually move much horizontally.

This is more dominant than anything

caused by the wind, so it doesn't

depend on wind direction, although

secondary swells may well do. It's

extremely dangerous to land into

Operational Procedures 147

wind without regard to sea

conditions; the swell must be taken

into consideration, although it could

assume less importance if the wind is

very strong.

The vast majority of swells are lower

than 12-15 feet, and the swell face is

the side facing you, whereas the

backside is away from you. This

seems to apply regardless of the

direction of swell movement.

The Procedure

You will need to transmit all your

MAYDAY calls and squawks (7700)

while still airborne, as well as turning

on your ELT, or SARBE. If time

permits, warn the passengers to don

their lifejackets (without inflating

them, or the liferafts) and tighten

seat belts, remove any headsets, stow

any loose items (dentures, etc.) and

pair off for mutual support, being

ready to operate any emergency

equipment that may be to hand (they

should have been briefed on this

before departure).

One passenger should be the

"dinghy monitor", that is, be

responsible for the liferaft. If it's

dark, turn on the cabin lights and

ensure everyone braces before

impact (the brace position helps to

reduce the flailing of limbs, etc. as

you hit the water, although its

primary purpose is to stop people

sliding underneath the lap strap;

there are different ones for forward

and aft seats).

If only one swell system exists, the

problem is relatively simple—even if

it's a high, fast one. Unfortunately,

most cases involve two or more

systems running in different

directions, giving the sea a confused

appearance. Always land either on

the top, or on the backside of a swell

in a trough (after the passage of a

crest) as near as possible to any

shipping, meaning you neither get

the water suddenly falling away from

you nor get swamped with water,

and help is near.

Although you should normally land

parallel to the primary swell, if the

wind is strong, consider landing

across if it helps minimise

groundspeed (although in most cases

drift caused by crosswind can be

ignored, being only a secondary

consideration to the forces contacted

on touch-down). Thus, with a big

swell, you should accept more

crosswind to avoid landing directly

into it. The simplest way of

estimating the wind is to examine

the wind streaks on the water which

appear as long white streaks up- and

downwind. Whichever way the foam

appears to be sliding backwards is

the wind direction (in other words,

it's the opposite of what you think),

and the relative speed is determined

from the activity of the streaks

themselves. Shadows and whitecaps

are signs of large seas, and if they're

close together, the sea will be short

and rough. Avoid these areas as far

as possible—you only need about

500' or so to play with.

The behaviour of the aircraft on

making contact with the water will

vary according to the state of the sea;

the more confused and heavy the

swell, the greater the deceleration

forces and risks of breaking up

(helicopters with a high C of G, such

as the Puma, will tip over very easily,

and need a sea anchor to keep them

stable – in fact, the chances of any

helicopter turning upside down are

quite high). Landing is less

148 Operational Flying

hazardous in a helicopter because

you can minimise forward speed. In

fact, if you are intentionally ditching,

you should come to a hover above

the water first, then throw out the kit