Silkway winter ops 2012

SILKWAY WEST WINTER OPERATIONS NEWSLETTER 2012

I know the temperature outside our hotel in Baku is still in the low 20’s (that would be the
mid 70’s for some of us) however, winter will soon be upon us, so I thought now would be
a good time to revisit and refresh our knowledge of winter operations!

This newsletter is directed at both our Boeing 767 and Boeing 747 pilots. However, the
type specific technical information is derived from the Boeing 747 manuals, for this I
apologise to our Boeing 767 pilots. I shall be asking for one of our Boeing 767 Training
Captains to produce an appendix to this newsletter which will cover the Boeing 767 type
specific information.

The topics covered will come under the following headings:

1. Review of cold weather general operations and latest information from Boeing.
2. Low Visibility general operations and definitions.
3. Boeing Flight Crew Training Manual information.
4. Cold weather supplementary procedures.

This newsletter is not all encompassing, there will be topics which I haven’t covered but
some of you may believe I should have done. In that case just drop me a line and I’ll
strive to add that subject to the next edition!

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REVIEW OF COLD WEATHER GENERAL OPERATIONS

A thorough understanding of all adverse and cold weather operational procedures needs
to be completely understood by all cockpit crew members. As we are all aware there
have been many aircraft crashes which have been the result of incorrectly de-iced
aircraft, and misunderstanding the information sent from iced up pitot static systems.
Hopefully the following information will re-enhance our knowledge of cold weather
winter operations.

Safe winter operations require special procedures by airline maintenance, engineering,
flight, and de-icing personnel. These procedures include de-icing, anti-icing, cold
weather maintenance, and flight operations.

The “clean-airplane” concept states, “No person may take off an aircraft when frost, ice
or snow is adhering to the wings, control surfaces, propellers, engine inlets, or other
critical surfaces of the aircraft. Take-offs with frost under the wing in the area of the fuel
tanks can be authorized. Dispatch or take-off any time conditions are such that frost, ice,
or snow may reasonably be expected to adhere to the airplane, unless the certificate
holder has an approved ground de-icing/anti-icing program in its Operations
specifications that includes holdover time (HOT) tables.

The clean-airplane concept describes an airplane that is aerodynamically clean —that is,
free of frozen contaminants. The clean-airplane concept is important because airplane
take-off performance is based upon clean surfaces until lift-off.

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An airplane is designed using the predictable effects of airflow over clean wings.
Contaminants such as frost, ice, or snow adhering to the wings disturb this airflow,
resulting in reduced lift, increased drag, increased stall speed, potentially severe roll
problems due to uneven lift, and possible abnormal pitch characteristics.

Airplane operation in cold weather conditions can cause special problems because of
the effects of frost, ice, snow, slush, and low temperature. The airplane maintenance
manual (AMM) provides procedures for removal of contaminants from the airplane and
the prevention of subsequent accumulation of frost, ice, snow, or slush. In addition, the
operator must ensure that the maintenance procedures for winter operations are
appropriate for the weather conditions. Boeing recommends that maintenance and
ground crew personnel and contracted airplane de-icing service providers acquaint
themselves with these recent developments in the area of airplane de-icing and anti-
icing: When thickened airplane de-icing/anti-icing fluids (i.e. SAE international Types ii,
iii, and iv fluids) dry, they may leave a very fine, powdery residue in critical areas in
wings and stabilizers. This residue can rehydrate and expand into gel-like materials that
can freeze during flight and cause restrictions in the flight control systems.

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As a result, operators should:

1. Be aware of how frequently airplanes are being de-iced/anti-iced.
2. Be aware of whether a one- or two-step application process is being employed.
While recognizing that it is not possible at some locations, Boeing recommends
using a two-step process, preferably with Type i fluid and/or hot water as the first
step. The application of hot water or heated Type i fluid as the first step of a two-
step process have been shown to minimize the formation of residue gels.
3. Ensure that proper procedures, including storage, handling, and application of
fluids, are being followed by airline personnel or contracted de-icing service
providers.
4. Establish an inspection and cleaning schedule for thickened fluid residue to help
ensure that no flight control restrictions will occur. Examine areas such as wing
rear spar, wing leading edge devices, horizontal stabilizer rear spar, vertical
stabilizer, auxiliary power unit bay, control tabs and linkages (when applicable),
and the bilge area of the tail cone. Visually inspect for dry or rehydrated residues
in these areas. This inspection and cleaning should be performed in accordance
with the recommendations found in the AMM for the specific airplane model
involved.
5. Apply lubricants and corrosion inhibitors as necessary to the areas where residue
cleaning occurs.

Airplane de-icing/anti-icing fluids and many runway de-icing fluids are not compatible
—interaction between the two may contribute to the formation of gel Residues. When
these fluids combine, the salts in some runway fluids enhance the separation of the
polymers contained in thickened airplane fluids, leading to a more rapid formation of gel
residues. When runway de-icing fluid contaminates thickened airplane anti-icing fluid,
there can be significant degradation of the fluid’s performance. HOT values can be
reduced and adherence or unacceptable flow-off may result. Runway de-icing fluid can
get onto the wings and tails by various means, such as spray from the nose gear, spray
kicked up by the engine exhaust of other airplanes, or from activation of the engine
thrust reversers. Runway de-icing fluids are hydroscopic fluids, so they don’t dry out
very quickly, causing them to leave a thin wet layer on the wing that can be difficult to
see. This implies that the use of hot water or Type i fluid to clean the wing prior to the
application of thickened anti-icing fluid (i.e., Type ii, iii, or iV) is even more important
than previously thought. On September 14, 2010, EASA issued Safety information bulletin
2010-26 on this subject, recommending the use of the two-step application process.

Winter or cold weather operations are generally associated with a combination of low
temperatures and frost, ice, slush, or snow on the airplane, ramps, taxiways, and
runways. The airplane flight manual (AFM) defines icing conditions as when the outside
air temperature (OAT) on the ground or total air temperature (TAT) in flight is 50 degrees
Fahrenheit (10 degrees Celsius) or less and any of the following exist:

1. Visible moisture (e.g., clouds, fog with visibility of one statute mile [1,600 meters]
or less, rain, snow, sleet, or ice crystals).
2. Ice, snow, slush, or standing water on the ramps, taxiways, or runways. On
runways contaminated by slush, snow, standing water, or ice, the use of fixed de-
rate reduced thrust is permitted, provided that airplane take-off performance
planning accounts for the runway surface condition.

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3. Use of the assumed temperature reduced thrust method, alone or in combination
with a fixed de-rate is not permitted on contaminated runways. Boeing does not
recommend take-offs when slush, wet snow, or standing water depth is more than
0.5 inch (13 millimetres) or dry snow depth is more than 4 inches (102
millimetres).

Boeing recommends that flight crews make themselves aware of the following recent
developments in the area of winter operations.

Starting with the 2010 winter season, HOT guidelines for Type i fluids include a new set of
times to be used when the fluids have been applied to composite surfaces. Testing
performed during the last three winter seasons has shown that HOT values for Type i
fluids on composite surfaces are significantly shorter (on the order of 30 percent) than for
aluminium surfaces. Extensive use of composites on newer models, and many older
models also have numerous composite surfaces (e.g. spoilers, ailerons, flaps, slats, etc.)

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During taxi-out, avoid using reverse thrust on snow- or slush-covered runways, taxiways,
or ramps unless absolutely necessary. Using reverse thrust on snow on slush-covered
ground can cause slush, water, and runway de-icers to become airborne and adhere to
wing surfaces.

Boeing currently provides two different landing-distance data sets to operators: dispatch
data and in-flight operational data. Dispatch landing data is used during flight planning
to determine the maximum landing weight at which the airplane can land within the
available landing distance at the destination or alternate airport. This data, referred to as
certified data in the AFM, is based on standard-day temperature and accounts for airport
pressure altitude and runway wind. However, it does not account for the effect of thrust
reversers or runway slopes. Non-dry runway conditions are accounted for by factoring
the dry runway dispatch landing-distance data. In-flight operational data is published as
advisory normal-configuration landing distance data in the performance in-flight section
of a Quick Reference Handbook (QRH).

The advisory data in the QRH for operators who use Joint Aviation Authorities or EASA
requirements includes a 1.15 factor for non-dry runway conditions. The advisory data
provided by Boeing is based on the use of reverse thrust and a 1,000-foot (305-meter)
flare distance.

De-icing removes accumulated frost, ice, or snow from an airplane, typically through the
application of hot water or a hot mixture of water and de-icing fluid; although there are
other approved methods for de-icing—such as infrared heat or hot air—the primary
method worldwide is the use of fluids.

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Anti-icing prevents the adherence of frost, ice, or snow to airplane surfaces for a certain
period of time (i.e., the HOT values). While the same fluids used for de-icing are also
used for anti-icing, SAE Types ii, iii, and iv fluids are more typically used for anti-icing
because they are thickened to stay on the airplane and thus provide longer HOT
Protection. They are most effective when applied unheated and undiluted to a clean
airplane surface.

Whether used for de-icing or anti-icing, the fluids must be transported, stored, and
handled properly to be effective. Operators must ensure that the fluid manufacturer’s
guidelines are followed for the entire de-icing/anti-icing process.

The SAE standards define four types of de-icing and anti-icing fluids.

1. Type i fluids are unthickened and typically have a minimum of 80 percent Glycol
and a relatively low viscosity, except at very cold temperatures. These fluids
provide some anti-icing protection, primarily due to the heat required for de-
icing, but have a relatively short HOT.
2. Type ii, iii, and iv fluids typically contain a minimum of 50 percent glycol in
addition to polymer thickening agents. The thickening agents delay the flow-off of
the fluids from the airplane surfaces. As a result, Type ii, iii, and iv fluids provide
longer HOT values than Type i fluids. The flow-off characteristics of Type iii fluids
make them more suitable for commuter airplanes with relatively low take-off
rotation speeds. Type iv fluids provide longer HOTs than Type ii fluids.

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Hold Over Time (HOT) is the length of time that anti-icing fluid will prevent ice and snow
from adhering to and frost from forming on the treated surfaces of an airplane. These
times are only guidelines; a number of variables can reduce protection time, including:

1. The heavier the precipitation, the shorter the HOT.
2. High winds or jet blast that cause the fluid to flow off, decreasing the protection
afforded by the fluid layer.
3. Wet snow, which causes fluids to dilute and fail more quickly than dry snow.
4. An airplane skin temperature lower than outside air temperature.
5. Direct sunlight followed by precipitation.
6. The use of incorrect equipment to apply fluids.

There are two methods for applying de-icing and anti-icing fluids.
One-step process: This process accomplishes both the de-icing and anti-icing steps
with a single fluid application. Typically a heated mixture of thickened fluid and water
is applied.
Two-step process: This process involves de-icing with heated Type i fluid, a heated
mixture of Type i fluid and water, or a heated mixture of water and thickened (Type ii, iii,
or iv) fluid, followed by a separate application of thickened fluid for anti-icing protection.
Experience and testing have shown that de-icing with heated Type i fluid or a heated
mixture of water and Type i fluid will help remove residue from previous anti-icing fluid
treatments. De-icing with heated thickened fluid may contribute to residue formation.

General Guidelines which apply to ground-crew but should also be known by flight crew
are as follows.
1. Ice that has accumulated on the fan blades while the airplane has been on the
ground for a prolonged stop is called “ground-accumulated ice” and must be
removed before engine start.
2. Ice that has accumulated on the fan blades while the engine is at idle speed is
called “operational ice” and is allowed to remain on the fan blades before taxi
because the ice will be removed by engine run-ups prior to take-off.
3. The right and left sides of the wing and horizontal stabilizer (including the
elevator) must receive the same fluid treatment, and both sides of the vertical
stabilizer must receive the same fluid treatment.
4. Treat the wings and tails from leading edge to trailing edge and outboard to
inboard.
5. Treat the fuselage from the nose and work aft. Spray at the top centre line and
work outboard.
6. Do not point a solid flow of fluid directly at the surfaces, gaps in airframe
structure, or antennas. Instead, apply the fluid at a low angle to prevent damage,
while pointing aft for proper drainage.
7. Make sure that all of the ice is removed during de-icing. There may be clear ice
below a layer of snow or slush that is not easy to see. As a consequence, it may be
necessary to feel the surface to adequately inspect for ice.
8. Do not spray de-icing/anti-icing fluids directly into auxiliary power unit (APU) or
engine inlets, exhausts, static ports, pitot-static probes, pitot probes, or TAT
probes.
9. Do not spray hot de-icing/anti-icing fluid or hot water directly on windows as it
may cause damage.
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10. Ensure that ice or snow is not forced into areas around flight controls during de-
icing.
11. Remove all ice and snow from passenger doors and girt bar areas before closing.
12. Cargo doors should be opened only when necessary. Remove the ice and snow
from the cargo containers before putting them on the airplane.
13. If SAE Type ii, iii, or iv fluids are used, remove all of the de-icing/anti-icing fluid
from the cockpit windows prior to departure to ensure visibility.
14. De-icing/anti-icing fluid storage tanks must be constructed of a compatible
material. For thickened fluids, the tanks must be of a material that is not
susceptible to corrosion (e.g., stainless steel or fiberglass). This is particularly
important for thickened fluids because their viscosity can be permanently
decreased if they are contaminated or exposed to excessive heat or mechanical
shear during handling and application.
15. When there is ice, slush, snow, or standing water on the runways or taxiways
during taxi-in, examine the airplane when it gets to the ramp. Look for any
damage to the airplane surfaces and for contamination that may have collected on
the airplane. Carefully remove the contamination.
16. Proper maintenance procedures for landing gear during cold weather operation
as defined in the AMM can help reduce degradation of the structural joints and
ensure optimal shock strut performance.
17. Operating during cold weather can adversely affect the ability to properly
lubricate the landing gear joints. Where possible, perform scheduled lubrication
at maintenance bases where the temperature is above freezing. A heated hangar
is the next most effective means of ensuring proper lubrication. If lubrication must
be accomplished outside a heated hangar in temperature below freezing, the
landing gear structure itself should be heated by blowing hot air directly onto the
structure or into an enclosure around the structure.
18. The temperature surrounding the airplane has a direct effect on both the volume
of the gas and the viscosity of the oil in the shock strut. Boeing multi-model
service letters provide procedures to ensure optimum strut performance if an
airplane operates between two different regions with significantly different
temperatures.
19. Do not point a spray of de-icing/anti-icing fluid directly onto wheels or brake
assemblies.
20. Remove contamination (e.g., frost, ice, slush, or snow) from the area where the
main and nose gear tires will be positioned when the airplane is parked at the
gate. If tyres are frozen to the ramp, the airplane should not be moved until they
are free.

The following are general guidelines which are applicable to flight deck crew, as
recommended by Boeing. However, the Boeing Flight Crew Operations manuals should
be referred to for definitive information.

Prior To Taxi:

1. Carefully inspect areas where surface snow, ice, or frost could change or affect
normal system operations. Perform a normal exterior inspection with increased
emphasis on checking surfaces, pitot probes and static ports, air-conditioning
inlets and exits, engine inlets, fuel-tank vents, landing-gear doors, landing-gear
truck beam, brake assemblies, and APU air inlets. Take-off with a light coating of
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frost (up to 1⁄8 inch [3 millimetres] thick) on lower wing surfaces caused by cold
fuel is allowable. However, all leading edge devices, all control surfaces, the
horizontal tail, vertical tail, and upper surface of the wing must be free of snow,
ice, and frost.
2. Perform the normal engine start procedures, but note that oil pressure may be
slow to rise. Displays may require additional warm-up time before engine
indications accurately show changing values. Displays may appear less bright
than normal.
3. Engine anti-ice must be selected on immediately after both engines are started,
and it must remain on during all ground operations when icing conditions exist or
are anticipated. Do not rely on airframe visual icing cues before activating engine
anti-ice. Use the temperature and visible moisture criteria.
4. Operate the APU only when necessary during de-icing/anti-icing treatment.
5. Do not operate the wing anti-ice system on the ground when thickened fluids
(e.g., SAE Type ii, iii, or iv) have been applied. Do not use the wing anti-ice
system as an alternative method of ground de-icing/anti-icing.
6. If the taxi route is through ice, snow, slush, or standing water, or if precipitation is
falling with temperatures below freezing, taxi out with the flaps up. Taxiing with
the flaps extended subjects flaps and flap devices to contamination.
7. Check the flight controls and flaps to ensure freedom of movement. If there are
any questions as to whether the airplane has frozen contamination, request de-
icing or proceed to a de-icing facility. Never assume that snow will blow off; there
could be a layer of ice under it. In rainy conditions with OAT near freezing, do not
assume that rain drops on surfaces have remained liquid and will flow off; they
could have frozen onto the surface. A similar issue can occur due to cold-soaked
fuel in the wing tanks.
8. Ice that has accumulated on the fan blades while the airplane has been on the
ground for a prolonged stop is called “ground-accumulated ice” and must be
removed before engine start.
9. Ice that has accumulated on the fan blades while the engine is at idle speed is
called “operational ice” and is allowed to remain on the fan blades before taxi
because the ice will be removed by engine run-ups prior to take-off.

DURING TAXI:

This guidance is applicable for normal operations using all engines during taxi.

1. Allowing greater than normal distances between airplanes while taxiing will aid
in stopping and turning in slippery conditions. This will also reduce the potential
for snow and slush being blown and adhering onto the airplane or engine inlets.
2. Taxi at a reduced speed. Taxiing on slippery taxiways or runways at excessive
speed or with strong crosswinds may cause the airplane to skid. Use smaller
nose-wheel steering and rudder inputs. Limit thrust to the minimum required.
3. Use of differential engine thrust assists in maintaining airplane momentum
through a turn. When nearing turn completion, placing both engines at idle thrust
reduces the potential for nose-wheel skidding. Differential braking may be more
effective than nose-wheel steering on slippery or contaminated surfaces.
4. Nose-wheel steering should be exercised in both directions during taxi. This
circulates warm hydraulic fluid through the steering cylinders and minimizes the
steering lag caused by low temperatures.

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5. During prolonged ground operations, periodic engine run-ups should be
performed per the Boeing FCOM to shed the accreted ice.

BEFORE / DURING TAKE-OFF:

1. Do the normal before Take-off Procedure. Extend the flaps to the take-off setting
at this time if they have not been extended because of slush, standing water, icing
conditions, or because of de-icing/anti-icing.
2. Verify that airplane surfaces are free of ice, snow, and frost before moving into
position for take-off.
3. In icing conditions, refer to the Boeing FCOM for guidance regarding static
engine run-up before take-off.
4. Before brake release, check for stable engine operation. After setting take-off
engine pressure ratio (EPR), or N1, check that engine indications are normal, in
agreement, and in the expected range. Check that other flight deck indications
are also normal.
5. Rotate smoothly and normally at Vr. Do not rotate aggressively when operating
with de-icing/anti-icing fluid.
6. Retract flaps at the normal flap retraction altitude and on the normal speed
schedule.
7. A larger temperature difference from international Standard Atmosphere (ISA)
results in larger altimeter errors. When the temperature is colder than ISA, true
altitude is lower than indicated altitude. Consider applying the Boeing FCOM
cold Temperature Altitude corrections, especially where high terrain and/or
obstacles exist near airports in combination with very cold temperatures (-22
degrees F/-30 degrees c or colder). Operator coordination with local and en-
route air traffic control facilities is recommended.

FROM THE BOEING 747-400 QRH.
Cold Temperature Altitude Correction.
Extremely low temperatures create significant altimeter errors and greater potential for
reduced terrain clearance. When the temperature is colder than ISA, true altitude will be
lower than indicated altitude.
The following altitude correction procedures should be considered when operating at or
near airports where high terrain and /or obstacle exist in combination with very cold
temperature (-30°C or colder), or when en-route minimum altitudes are affected by terrain
clearance:
• No corrections are required for reported temperature above 0°C
• Corrections apply to QNH operations
• Pilots should not correct altimeter barometric reference settings
• ATC assigned altitudes or flight levels should not be adjusted for temperature
• Apply corrections to all published minimum departure, en-route and approach altitudes,
including missed approach altitudes according to the table below.
Advise ATC of the corrections
• MDA/DA settings should be set at the corrected minimum altitudes for the
approach.
• Subtract the elevation of the altimeter barometric reference setting source (normally the
departure or destination airport elevation) from the published minimum altitude to be flown
to determine “height above altimeter source”

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• Enter the QRH table with Airport Temperature and with “height above altimeter source”.
Read the correction where these two entries intersect. Add the correction to the published
minimum altitude to be flown to determine the corrected indicated altitude to be flown. To
correct an altitude above the altitude in the last column, use linear extrapolation (e.g., to
correct 6000 feet or 1800 meters, use twice the correction for 3000 feet or 900 meters,
respectively)
• If the corrected indicated altitude to be flown is between 100 foot increments, set the MCP
altitude to the closest 100 foot increment above the corrected indicated altitude to be flown.

DESCENT:

1. Unless the airplane has fully automatic activation of ice protection systems,
anticipate the need for activating the engine and/or wing anti-ice systems at all
times, especially during a descent through instrument meteorological conditions
or through precipitation.
2. When anti-ice systems are used during descent, be sure to observe Boeing FCOM
minimum EPR/N1 limits (if applicable).

LANDING:

1. The flight crew must be aware of the condition of the runway with respect to ice,
snow, slush, or other contamination.
2. Follow the normal procedures for approach and landing. Use the normal
reference speeds unless otherwise directed by the Boeing FCOM.
3. Arm the autobrake and autospoiler systems, if available, before landing.
4. The airplane should be firmly flown onto the runway at the aiming point.
5. Immediately after main-gear contact with the runway, deploy the speedbrakes if
not already deployed by the automatic system.
6. Without delay, lower the nose-wheel to the runway to gain nose-wheel directional
control. Do not hold the nose gear off the runway when operating on slippery or
icy runways.
7. Use of autobrakes is recommended. They will allow the pilot to better concentrate
on directional control of the airplane. If manual braking is used, apply moderate
to firm steady pedal pressure symmetrically until a safe stop is assured.
8. Let the anti-skid system do its work. Do not pump the brake pedals.
9. Do not use asymmetric reverse thrust on an icy or slippery runway unless
necessary to arrest a skid.
10. When using reverse thrust, be prepared for a possible downwind drift on a
slippery runway with a crosswind.
11. During winter operations, it is even more important than usual that the flight crew
not attempt to turn off the runway until the airplane has slowed to taxi speed.
12. Taxi at a reduced speed. Taxiing on slippery taxiways or runways at excessive
speed or with strong crosswinds may cause the airplane to skid.
13. The cold Weather operations Supplementary Procedure in the Boeing FCOM
specifies how far the flaps may be retracted after landing in conditions where ice,
snow, or slush may have contaminated the flap areas. If the flap areas are found to
be contaminated, flaps should not be retracted until maintenance has removed
the contaminants.
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14. Use the engine anti-ice system during all ground operations when icing
conditions exist or are anticipated.

LOW VISIBILITY REFRESHER

Obviously with winter operations looming, we will be required to complete Low
Visibility Approaches and Autolands in decreased visibilities.
The following is just a reminder of what Low Visibility Procedures entail.

LVO is a procedure recommended by ICAO to be implemented by the Airport
AUTHORITIES when weather conditions fall below or are expected to fall below 800
meters RVR or 200 feet cloud base to ensure a sterile localizer sensitive area (LSA). Pilots
can expect ILS localizer and glide path signals to be fully protected from interference
during the final approach, from the time that the pilots are notified that LVOs are in
operation until the time that pilots are notified that LVOs have been cancelled.

DECISION HEIGHT

A specified height in the precision approach at which a missed approach must be
initiated if the required visual reference to continue the approach has not been
established. Decision height is referenced to runway threshold elevation.

1. ILS Category I
ILS approach procedure which provides for an approach to a decision height not lower
than 200 ft. and a visibility of not less than 800 meters or an RVR of not less than 550
meters.
2. ILS Category II
ILS approach procedure which provides for an approach to a decision height not lower
than 100 ft and an RVR of not less than 300 meters.
3. ILS Category IIIA
ILS approach procedure which provides for an approach to a decision height lower than
100 ft or no decision height and with an RVR of not less than 200 meters.
4. ILS Category IIIB
ILS approach procedure which provides for an approach to a decision height of 17 ft and
an RVR of not less than 125 meters.

FAIL OPERATIONAL and FAIL PASSIVE AUTOPILOT SYSTEMS

It is important to understand the difference between these as CAT II/III operation is
based on these concepts.
Fail Operational
Means that in the event of failure of one channel, the approach, flare and landing can be
completed by the remaining part of the automatic system. After failure of one channel out
of three the aircraft would become FAIL-PASSIVE.

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Fail Passive
Means that in the event of a failure of one further channel, there is no significant out-of-
trim condition or deviation from the flight path or aircraft attitude. It does mean however
that the automatic system is no longer able to carry out the automatic landing. Should one
channel fail during the approach the Autoland capability is lost.

LOW VISIBILITY TAKE-OFF

A Take-Off when the reported RVR is 400m or less.

A take-off minimum of 125 m may be used under the following conditions:
• Low visibility procedures are in force.
• High intensity runway centreline lights spaced 15 m or less and high intensity edge
lights spaced 60m or less are in operation.
• Crews have satisfactorily completed training in a simulator approved for this
procedure.
• Visual segment for 125m RVR, is such that 90M is visible from the cockpit at the start of
take-off run and the required RVR value has been achieved for all of the relevant RVR
reporting points.
• ILS Localizer will be tuned in for runway in use with visibility.

Alternate Airports for departure

Departure weather minima at an aerodrome shall not be lower than Category I minimum
or the applicable higher non-precision approach for that aerodrome unless a take-off
alternate aerodrome is available which meets all the relevant landing minima and
performance requirement for the aeroplane type e.g. engine inoperative limitation and
loss of Category II/III capability .Take-off alternate shall not net be more than one hour
flight time for two engine aircrafts, and two hour for four engine aircrafts, at One Engine
inoperative cruising speed according to the AFM in still air standard conditions based on
the actual take-off mass.

Rejected Take-off

If it is necessary to abandon the take-off and visibility is very limited, directional control
with reference to the centreline lights may become relatively less easy as speed is
reduced. Apply full braking to ensure aircraft stops before end of runway. As soon as the
centreline lights change to alternate red and white there is 900m of runway left and
groundspeed should certainly not be greater than 90 kt. When only 300m of runway
remains the centreline changes to continuous red lights.

THE APPROACH BAN

The CAT II or III approach may NOT be continued beyond the FAF, if the reported RVR is
below the published minima. If, after passing the Outer Marker or equivalent position,
the reported RVR/Visibility falls below the applicable minimums, the Commander may
continue the approach to DA/H or MDA/H.
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Where no Outer Marker or equivalent position exists, the Commander shall make a
decision to continue or abandon the approach before descending below 1000 ft above
the aerodrome on the final approach segment.
The approach may be continued below DA/H or MDA/H and the landing completed
provided that the required visual reference is established at the DA/H or MDA/H and is
maintained.

With RVRs between CAT II and CAT IIIB minimum's, the pilot has a VISUAL SEGMENT that
will take, (at 160 knots) between 4 seconds (RVR 300m) and 1 second (RVR 550m) to
traverse. Obviously this makes it difficult - if not impossible - to assess precisely what the
visibility is. There is no time to start counting lights. The pilot also has little time to assess
the trend in visibility as the aircraft progresses towards and along the runway. It is
therefore considered prudent to prohibit the start (or continuation) of an approach if
conditions at DH are likely to be unfavourable for a successful landing.
Why does the APPROACH BAN apply up to the OM but not after? This due to the fact that
if the RVR was above minima up to the OM but has since deteriorated then there is likely
a fluctuating RVR situation present. The Approach is allowed to continue as there is still a
reasonable chance of improvement in RVR. This also minimizes crew distraction caused
by continual RVR readouts during the approach.
The visibility associated with fog is by no means uniform and it is not uncommon for the
visibility to reduce over a very short distance. Thus after touchdown and reverse thrust
deployment the pilot may encounter very rapid reduction of visibility in the runway mid-
zone.

REQUIRED VISUAL REFERENCE

That section of the visual aids or of the approach area which should be in view for
sufficient time for the Pilot to make an assessment of the aircraft position and rate of
change of position in relation to the desired flight path.

Visual Reference, Category II/IIIA
A pilot may not continue an approach below the applicable decision height (DH) unless
the following visual reference is attained and can be maintained:
• segment of at least 3 consecutive lights being the centreline of the approach lights; or
Touchdown zone lights; or
• Runway centreline lights; or
• Runway edge lights or a combination of the required visual references above.

NOTE…..CAT II
This visual reference must include a lateral element of the ground pattern, i.e. an
approach lighting crossbar or the landing threshold or a barrette of the touchdown zone
lighting.

15


BOEING FLIGHT CREW TRAINING MANUAL REVIEW

Once again we should have a thorough knowledge of winter operations as described in
the Boeing FCOM. I have selected some topics as revision but they are not limiting.

1. Our Boeing FCTM states that fluctuating and inaccurate airspeed and altimeter
indications after take-off have been attributed to static ports obstructed by ice
formed while the airplane was on the ground. Precipitation or water rundown
after snow removal may freeze on or near the static ports. This may cause an ice
build-up which disturbs airflow over the static ports resulting in erroneous
airspeed and altimeter readings, even when static ports appear to be clear. Since
static ports and the surrounding surfaces are not heated when probe heat is
activated, a thorough pre-flight inspection and clearing of all contaminants
around the static ports are critical. The aircrew should pay particular attention to
the static ports during the exterior inspection when the airplane has been
subjected to freezing precipitation. Clear ice on the static ports can be difficult to
detect. If in doubt, contact maintenance for assistance.

2. When taxiing on a slippery or contaminated surface, particularly with strong
crosswinds, use reduced speeds. Use of differential engine thrust assists in
maintaining airplane momentum through the turn. When nearing turn completion,
placing all engines to idle thrust reduces the potential for nose gear skidding.
Avoid using large nose wheel steering inputs to correct for skidding. Differential
braking may be more effective than nose wheel steering on slippery or
contaminated surfaces. If speed is excessive, reduce speed prior to initiating a
turn. Note: A slippery surface is any surface where the braking capability is less
than that on a dry surface. Therefore, a surface is considered “slippery” when it is
wet or contaminated with ice, standing water, slush, snow or any other deposit
that results in reduced braking capability. During cold weather operations, nose
gear steering should be exercised in both directions during taxi. This circulates
warm hydraulic fluid through the steering cylinders and minimizes the steering
lag caused by low temperatures. If icing conditions are present, use anti-ice as
required by the OM. During prolonged ground operations, periodic engine run-
ups should be accomplished to minimize ice build-up. These engine run-ups
should be performed as defined in the OM. Engine exhaust may form ice on the
ramp and take-off areas of the runway, or blow snow or slush which may freeze on
airplane surfaces. If the taxi route is through slush or standing water in low
temperatures, or if precipitation is falling with temperatures below freezing, taxi
with flaps up. Extended or prolonged taxi times in heavy snow may necessitate
de-icing prior to take-off.

3. A slippery runway (wet, compact snow, ice) also increases stopping distance
during a rejected take-off. Take-off performance and critical take-off data are
adjusted to fit the existing conditions. Note: If there is an element of uncertainty
concerning the safety of an operation with adverse runway conditions, do not
take-off until the element of uncertainty is removed. During wet runway or
slippery conditions, the PM must give special attention to ensuring that the thrust
on the engines advances symmetrically. Any tendency to deviate from the runway
centreline must immediately be countered with steering action and, if required,
slight differential thrust. Forward pressure on the control column during the initial
16


portion of the take-off roll; (below approximately 80 knots) increases nose wheel
steering effectiveness. Note: On very slippery runways, over control of the
rudder pedal during initial acceleration can quickly destabilize directional
control. During take-offs on icy runways, lag in rudder pedal steering and
possible nose wheel skidding must be anticipated. Keep the airplane on the
centreline with rudder pedal steering and rudder. The rudder becomes effective
between 40 – 60 knots. If deviations from the centreline cannot be controlled
either during the start of the take-off roll or until the rudder becomes effective,
immediately reject the take-off.

4. Slippery Runway Landing Performance. When landing on slippery runways
contaminated with ice, snow, slush or standing water, the reported braking action
must be considered. Advisory information for reported braking actions of good,
medium and poor is contained in the PI section of the QRH. The performance level
associated with good is representative of a wet runway. The performance level
associated with poor is representative of a wet ice covered runway. Also provided
in the QRH are stopping distances for the various autobrake settings and for non-
normal configurations. Pilots should use extreme caution to ensure adequate
runway length is available when poor braking action is reported. Pilots should
keep in mind slippery/contaminated runway advisory information is based on an
assumption of uniform conditions over the entire runway. This means a uniform
depth for slush/standing water for a contaminated runway or a fixed braking
coefficient for a slippery runway. The data cannot cover all possible
slippery/contaminated runway combinations and does not consider factors such
as rubber deposits or heavily painted surfaces near the end of most runways.

COLD WEATHER SUPPLEMENTARY PROCEDURES

Nacelle Anti–Ice Operation – On the Ground
Nacelle anti–ice must be selected ON immediately after all engines are started and
remain on during all ground operations when icing conditions exist or are anticipated
except when temperature is less than -40°C.

WARNING: Do not rely on airframe visual icing cues before activating nacelle anti–
ice. Use the temperature and visible moisture criteria because late activation of
engine anti-ice may allow excessive ingestion of ice and result in damage or
failure.

CAUTION: Do not use nacelle anti-ice when OAT is above 10° C.

When nacelle anti–ice is needed:
Nacelle anti-ice ............................................................................. ON
When nacelle anti-ice is no longer needed:
Nacelle Anti-ice .......................................................................AUTO

17


Before Taxi Procedure:

Do the normal Before Taxi Procedure with the following modifications:
If taxi route is through ice, snow, slush, or standing water in low temperatures or if
precipitation is falling with temperatures below freezing, taxi out with the flaps up.
Taxiing with the flaps extended subjects the flaps and flaps drives due to contamination.
Leading edge flaps are also susceptible to slush accumulations.

Taxi-Out:

CAUTION: Use extreme caution when taxiing on ice-covered taxiways or runways,
as excessive speed or high crosswinds may start a skid. Make all turns at a reduced
speed. Use smaller tiller and rudder inputs, apply minimum thrust evenly and
smoothly.

When nacelle anti-ice is required and the OAT is 3°C or below, do an engine run up, as
needed, to minimize ice build-up. Use the following procedure:

Check area behind airplane is clear.
Run-up to a minimum of 60% N1 and a maximum of 65% N1 for approximately 30
seconds duration at intervals no greater than 60 minutes.

De-Icing / Anti—Icing

Testing of undiluted de-icing/anti-icing fluids has shown that some of the fluid remains on
the wing during take-off rotation and initial climb. The residual fluid causes a temporary
decrease in lift and increase in drag, however, the effects are temporary. Take-off
operations with reduced thrust (assumed temperature method or fixed derate) are
permitted provided take-off performance accounts for the runway surface condition. Use
the normal take-off rotation rate.

CAUTION: Operate the APU during de-icing only if necessary. If the APU is
running, ingestion of de-icing fluid causes objectionable fumes and odours to enter
the airplane. Ingestion of snow, slush, ice, or de-icing/anti-icing fluid can also
damage to the APU.

If de-icing / anti-icing is needed:
APU ....................................................................................As needed
The APU should be shut down unless APU operation is necessary.
Call “FLAPS UP”.
Flaps ...............................................................................................UP
Prevents ice and slush from accumulating in flap cavities during de-icing.
Thrust levers ................................................................................. Idle
Reduces the possibility of injury to personnel at inlet or exhaust area.
Packs ............................................................................................OFF
Reduces the possibility of fumes entering the air-conditioning system.
APU bleed air switch (APU running) ..........................................OFF
Reduces the possibility of fumes entering the air-conditioning system.

18


After de-icing / anti-icing is completed:
APU .............................................................................. As needed
APU bleed valve switch (APU running) ................................. ON
Wait approximately one minute after de-icing is completed to turn pack selectors on to
ensure all de-cing fluid has been cleared from the engines.
Packs ........................................................................................ ON

Before Take-off Procedure:

Do the normal Before Take-off Procedure with the following modification:
Call “FLAPS ___” as needed for take-off.
Flaps lever ............................................... Set take-off flaps, as needed. Extend flaps to
take-off setting at this time if they have been held due to slush, standing water, or icing
conditions, or because of exterior de-icing / anti-icing.

Take-off Procedure:

Do the normal Take-off Procedure with the following modifications.
When nacelle anti-ice is required and the OAT is 3°C or below, do an engine run-up, as
needed, to minimize ice build-up; and use the following procedure:
Run-up to a minimum of 60% N1 for approximately 10 seconds duration and confirm
stable engine operation before the start of the take-off roll.

Fan Ice Removal:

CAUTION: Avoid prolonged operation in moderate to severe icing conditions.

If moderate to severe icing conditions are encountered:
During flight in moderate to severe icing conditions for prolonged periods, if fan icing is suspected
due to high engine vibration (exceeding 2.5 units), the fan blades must be cleared of any ice. Do the
following procedures on all engines, one engine at a time: quickly reduce thrust to idle for five
seconds, and then restore the required thrust.
If vibration persists, advance thrust lever to 90% N1 momentarily.

19


SUMMARY

I hope that this newsletter has refreshed our views on some of the requirements for winter operations.
It is not an exhaustive piece on this subject. I suggest that we also review our other documentation
which we have available, especially the Flight Planning and Performance Manual and the Minimum
Equipment List.

Also please read the Boeing bulletin which applies to engine core icing, as this scenario will be
occurring shortly, especially in places like Urumqi.

Number: SYK-14 R1
IssueDate: January 7, 2011
Airplane Effectivity: All Airplanes
Subject: New Core Ice Shedding Procedure When Operating in Freezing Fog
Reason: To inform flight crews of a special ice shedding procedure that can beused in
freezing fog conditions.
Introduction
Operators exposed to freezing fog who wish to minimize the risk of unplanned engine
removals associated with ice damage to the engine core may use a new, optional core ice
shedding procedure. The boroscope inspection requirements following exposure to
freezing fog in the Aircraft Maintenance Manual (AMM) remain in effect.
Background Information
Boeing has received reports of internal engine damage on RB211-524 powered 747-400
airplanes. The damage occurred after extended idle thrust operation in freezing fog. In
freezing fog, ice can build up in the core of the engine as well as on the fan blades.
Analysis has shown the current RB211-524 ground engine ice shedding procedure, which
requires operation at 60% N1 for 10 seconds every 60 minutes is adequate for shedding fan
blade ice accumulations but may not always shed core ice accumulations in freezing fog
conditions.
Analysis has also shown extended exposure to freezing fog conditions below -13°C can
create ice accumulations impractical or impossible to shed using ground run-up
procedures. The use of engine anti-ice on the ground will not prevent ice accumulations on
the fan blades or in the core of the engine. An engine that experiences freezing fog on taxi
in to the gate will not shed the ice when the engine is shut down in cold temperatures. For
this reason, the total engine running time of taxi in and taxi out, including warm up and cool
down times, in freezing fog must be considered.
A new, optional core ice shedding procedure has been developed for operations in freezing
fog. This procedure does not apply to operations in snow, hail, sleet, freezing rain, or
freezing drizzle. These condition have a larger water particle size that does not cause ice
accumulation in the core of the engine.
Boeing and Rolls Royce recommend using the new, optional core ice shedding procedure
any time total taxi time in freezing fog (FZFG as reported in the METAR) exceeds 30 or 45
minutes, dependent on ambient air temperature, when visibility is 900 feet (300 meters)
RVR or less as reported in the METAR. In freezing fog, inbound flight crews must make a log
book entry of the total number of minutes taxiing in when visibility is 300 meters RVR or less
so the subsequent outbound flight crew can calculate the total taxi time in these conditions.

20


Operating Instructions
Flight crews may use the new, optional core ice shedding procedure for RB211-524 engines
when freezing fog (FZFG) with visibility of 900 feet (300 meters) RVR or less is reported in
the METAR to minimize compressor damage.
Note: If taxi in on the previous flight occurred in freezing fog and the temperature stayed
below freezing, the taxi in time from the previous flight must be included in the total time. If
the engine is considered free of ice before engine start, only the taxi out time should be
included in the total time. The engine is considered free of ice before engine start if:
• the engine has been manually de-iced, or
• the engine has been visually inspected per the AMM, or
• the core ice shedding procedure was conducted within 5 minutes
of engine shutdown after taxi in.
If the subsequent take-off cannot be accomplished within 45 minutes total taxi time for a
OAT of 0°C to -6°C, or 30 minutes for an OAT of -7°C to -13°C, accomplish the new core ice
shedding procedure to clear the ice from the engine core. The core ice shedding procedure
should be accomplished at intervals no greater than every 30 or 45 minutes, dependent on
OAT, before take-off.
For an OAT of -14°C or below, if the subsequent take-off cannot be accomplished within 30
minutes total taxi time, manual de-icing is needed. To avoid manual de-icing requirements,
operators are encouraged to work with airport authorities to limit or eliminate exposure to
extended taxi times when freezing fog conditions exist.
If the subsequent take-off can be accomplished within 45 minutes total taxi time for an OAT
of 0°C to -6°C, or 30 minutes total taxi time for an OAT of -7°C or below, the new core ice
shedding procedure does not need to be done.

CAUTION: As with all engine run-ups, precautions must be taken for:
• jet blast up to 600 feet (200 meters) behind the aircraft
• snow and ice at the edge of the taxiway that can be ingested by the engines
• slippery taxi surfaces
• airport noise restrictions.

NOTE! THE ABOVE IS NOT THE COMPLETE BULLETIN, SO PLEASE REFER TO IT IN
VOLUME 1……..

FINALLY!
As an aside I would just like to remind us all that the MEL applies up until the setting of take-off
thrust. Within the MEL there are many references to unserviceable items and systems which affect
our operation in cold weather, IMC and icing conditions which I suggest that we all have a look at
from time to time when at a quiet time in the cruise.
Just to reiterate all pilots, co-pilots and captains alike need to have a thorough understanding of these
adverse weather procedures.

Please e-mail me with your comments or criticisms and I will endeavour to use your ideas to improve
the next newsletter. (cla747@hotmail.com)

Many thanks.

Alan Carter.

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Silkway winter ops 2012

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