winter ops 800

RYANAIR WINTER OPERATIONS & PROCEDURES stRevision 1 - Sept 01 2002

Winter Operations Page 0

WINTER OPERATIONS 1.0 INDEX Page 0 1.1 GENERAL 1.2 PRE-FLIGHT PLANNING Page 2 1.3 START-UP AND TAXI Page 6 1.4 TAKE-OFF LIMITATIONS Page 8 1.5 RUNWAY CONDITION REPORTS Page 10 1.6 REPORTING OF RUNWAY CONDITIONS BY ATC Page 11 1.7 IN-FLIGHT PROCEDURES Page 14 1.8 LANDING Page 16 1.9 OVERNIGHT CHECKS & SECURITY Page 17 1.10 SNOWTAMS DECODE Page 18 1.11 DE-ICING FLUIDS Page 22 1.12 HOLDOVER TABLES Page 24 1.13 COLD WEATHER ALTIMETER CORRECTION Page 28



WINTER OPERATIONS 1.1 GENERAL

This section provides Ryanair B737-Ng crews with essential operational information to conduct safe Ground and Flight Operations during winter months. A general review of hazards associated with Winter Operations is also included for completeness.

Crews should review this document prior to winter operations. The Boeing

Operations Manual Volume 1, the Flight Crew Training Manual, Ryanair Operations Part ‘A’ and Part ‘B’ provide additional information.

This manual references the above publications in its content and is hopefully a

concise and informative guide to your pre-winter preparations. There have been many developments in the field over the past few years that you

may or may not be aware of. Take a few minutes to refresh your memory and help keep our Operation SAFE and STANDARD over the coming winter period.

Remember, the colleague sitting next to you may well be relying on your

experience to lead him through a first winter;

• Be patient • Pass on FACT only • Share the workload • Use spare time to plan ahead • Always double check • And above all – DO NOT RUSH YOUR OPERATION!

***********************



1.2 PRE-FLIGHT PLANNING

1 Fully check all available meteorological information, particularly noting icing levels, the possibility of and degree of airframe icing that may be encountered. This information may indicate the need to revise the planned route, flight level or diversion policy.

2 The B737-Ng is certified as having an icing protection system

which allows safe flight through continuous and intermittent maximum icing, as defined in FAR Part 25.1419, dated February 1, 1965.

3 Airplane Requirements & Considerations

Comply with all current Boeing Bulletins and Limitations

Caution: Do not move control surfaces without alerting ground crew.

Ensure that the following areas are clear of any frozen

contaminants: -

Upper surface of BOTH wings, including ailerons and tabs

Lower surface of BOTH wings if ice depth is greater

than 3mm

Stabilizer and elevator assembly

Rudder and fin area

Landing gear and doors

Radome area especially below the flight deck windows (do not spray de-icing fluid directly onto any a/c windows)



Door areas and escape hatches

Upper fuselage as necessary (with pre-conditioned air

entering the cabin, de-icing the fuselage may be avoided). Thin hoar frost on the upper surface of the fuselage is acceptable provided all vents and ports are clear

Control Balance cavities

Air conditioning inlets and exits

Engine inlets

APU air inlet – must be clear before attempting an

APU start

Pitot Probes and Static Ports – Check all pitot probes and static ports are free of ice and snow. Water rundown after snow removal may refreeze immediately forward of static ports and cause an ice buildup which disturbs airflow over the static ports resulting in erroneous readings even when the static ports themselves are clear – Hot air clearing only

To ensure adequate draining of de-icing fluid from

the tail area, the PF should ensure that full Nose Down trim is applied to the Stabilizer before de-icing commences

After de-icing and anti-icing procedures have been

completed, obtain clearance from the ground crew and cycle the elevator slowly through three complete cycles. This will help to ensure drainage of the fluid. Reposition the stabilizer to the takeoff position during the pre-flight scan



The front fan blade (rear edge) on the B737 is highly

susceptible to clear icing buildup when freezing fog conditions exist. Icing in this region may only be cleared using hot air

Always use approved de-icing/anti-icing fluid(s) to effectively remove any contamination and provide a conservative holdover capability. Guidance as to the effectiveness of protection is given below

Note 1 – It is acceptable to de-ice/anti-ice both wings and

exclude the tailplane from the process, providing the tailplane is free from contaminants. It is not permitted to apply fluid asymmetrically across the longitudinal axis of the airplane.

4 Under certain conditions, the fact that aircraft surfaces are

‘wetted’ with diluted anti-icing fluids may enhance the accumulation of wet snow, particularly if there is any significant delay between de-icing and take-off.

5 After de-icing, re-check the aircraft taking particular note of

control surfaces, flaps and their associated operating mechanisms, hinges and gaps.

6 Non Environmental Icing - (NEI) – Crews must be alert for

this particular type of icing. NEI will form as a result of cold soaked fuel in contact with the upper surface of each wing cooling the surrounding local air to below its dewpoint; at which point it will freeze adhering itself to the wing much like a morning frost develops. What is particularly surprising to crews experiencing this type of icing for the first time is that, as the name suggests, the environment is not the causing factor, but it is the aircraft itself that generates the process. It may well be CAVOK with an OAT as high as 25 degrees C, but if the following conditions are met, there is a highly likely prospect of NEI developing;

a Fuel temperature (sensor in the port wing) below freezing and

also below the dewpoint.



b Greater than approximately 2000 kgs of weathered fuel in

each main tank. c High humidity levels (I.e. OAT and dewpoint close together). After refueling is complete, crews must touch test the top

surface of each wing to determine whether de-icing is necessary. Normally TYPE I fluid is used to clear NEI, however TYPE II or IV may be necessary, particularly if the NEI is combined with rain on a cold soaked wing.

This form of icing is probably the most subtle and deadly combination that we may be exposed to on a regular basis.

The company fuel tankering policies allow for NEI considerations and crews are asked to follow the tankering policy and accept a possible de-icing process on arrival at destination. In order to expedite this process alert the Handling agents via R/T if you expect to need de-icing. Remember that they will not anticipate your requirements especially when summer conditions exist at their airfield. Refer to the ‘Airfield Briefs’ for airfields, such as Alghero, which do not have de-icing facilities available. Tankering into such airfields is not permitted. If an NEI situation occurs and de-icing is unavailable, it may be necessary to transfer weathered fuel from the main tanks to the centre tank using the de-fuelling valve. This process can be found in Boeing Operations Manual 1, Ground Transfer of Fuel SP.12.2. Subsequently warm fuel from the airfield will be uplifted into the main tanks allowing the ice on the top surface of the wings to melt.

7. JAR OPS 1.600 states: An Operator (Ryanair) shall ensure that

when the appropriate weather reports or forecasts, or a combination thereof, indicate that the runway at the ETA may be contaminated, the landing distance determined by using data acceptable to the authority for these conditions, does not



exceed the landing distances available. Ryanair designated airfields will provide snow clearing and

runway clearing facilities to coincide with the arrival of our aircraft. Practically speaking, snow clearing will commence at a suitable period prior to landing that will provide the best possible surface and friction levels. It is reasonable to assume during pre-flight planning, that moderate levels of snowfall will be within the capabilities of the snow clearing team. Therefore, QRH Performance Dispatch figures for Slippery Runway Landing Distances are acceptable to the authority provided a suitable Alternate is available with the required factored landing distances calculated before departure.

Prior to commencing an approach and landing, it must be determined by the crew that the landing distance required will not exceed the landing distance available.

1.3 START UP AND TAXI Supplementary procedures from Boeing Operations Manual Volume 1 should be reviewed paying close attention to Engine Start, After Start, Taxi Out and Before Takeoff items. SP.16.3 - SP.16.7. Start up and pushback clearance must be strategically requested (airfield dependent) to coincide with the completion of all de-icing processes. Pay particular attention to holdover time available against taxi duration. Pushback procedures should be accomplished as normal with the following caveats – Be aware of sloping ramps that may be contaminated. Pushback tugs may find it difficult to pushback up slope. Consider delaying engine start accordingly – Ground crews are working in a hostile environment made all the more so by slippery ramp areas. Ensure ground personnel do not infringe the engine inlet danger zones. When ground crews are clear of the airplane and icing conditions exist: -

• Visible moisture (clouds, fog with visibility less than one mile, rain, snow, sleet, ice crystals and so on) is present, or

• Standing water, ice or snow is present on ramps, taxiways or runways.



Switch ON airplane anti-icing systems. Note: Start Switches must be ON during all ground operations with Engine anti-ice ON. When TYPE I fluid has been used Wing anti-ice must be switched ON. If TYPE II or IV fluid has been used for anti-icing purposes, the Boeing manual gives crews the option of using wing anti-ice. Ryanair procedure is to switch wing anti-ice ON during all ground operations in icing conditions irrespective of fluid type used. Note: Except, when conducting Bleeds Off Takeoffs; or, when de-iced due to NEI and OAT is greater than 10 degrees C. Taxi with great caution as snow clearance of apron and taxiways is usually given a low priority and their condition may be inferior to that reported on runways. To avoid further contamination of your aircraft maintain a generous distance from any aircraft taxiing ahead. Consideration should be given to taxiing with flaps up to prevent slush being thrown up into the flap hinges; however, if this is done, the entire Before Takeoff Checklist will be accomplished at the holding point prior to entering the runway. The flight controls check will again be accomplished as normal, but will include a total of three elevator cycles in order to aid fluid drainage. Taxiways may be difficult to discern through significant depths of snow, if necessary, request the assistance of a follow me vehicle, whose driver will know the airfield intimately. The Captain will use his judgment when assessing taxiway conditions and their suitability but must make full use of airfield experts such as the friction test driver who can (on request) provide additional information regarding braking co-efficient (in more detail than the standard presentation), contamination type, etc. If significant depths of snow are present on taxiways, a ‘chock’ of snow will build up in front of main wheels and nose wheels causing considerable drag. Do not attempt to taxi out of the situation as damage may occur. Crews should notice this through the use of abnormally high power settings. Take maximum caution when taxiing on painted lines especially during line up. Do not accept any immediate takeoff clearances that will necessitate a speed higher than a slow walking pace throughout the line up procedure.



Note - Sweeping taxiways and runways does not always increase the braking co-efficient. It may sometimes even reduce the co-efficient. Crews should therefore accept the opinions of the experts who will be using their experience and training to provide you with the best possible surface. Also remember that the surface appearance of a taxiway or runway is not always a good indication of its friction level. Dry snow at 60mm depth may well have a better braking action than compacted snow with 6mm depth. Northern European airfields will be much more capable and reliable during winter operations when compared to Southern airfields in our network. Increased vigilance of your operation is required when operating through these airfields during winter months. Further information and guidance can be found in the following publications: Ryanair Operations Manual Part A and B Boeing Operations manual volume 1, 2 and the FCTM 1.4 TAKE-OFF LIMITATIONS

1 Adopt taxiing techniques which will avoid snow/slush adherence to the airframe or accumulation around flap/slat and/or landing gear areas. DO NOT use reverse thrust.

2 Take-offs should not be attempted in depths of contaminant

greater than those given in the Ryanair Operations manual Part B or the AFM whichever is limiting.

3 All braking systems serviceable 4 Flight Spoilers/Ground Spoilers fully functional 5 Both Reverse thrust systems functional

6 The use of Flap 5 or 15 is recommended



7 Do not tanker fuel to airfields with braking action less than

0.30.

Note: The Captain may elect not to tanker at his discretion or when the Slippery Runway Landing distance dictates a lower landing weight is required to comply with Authority regulations.

8 Confirm that appropriate de-icing/anti-icing precautions have been met for the current weather conditions and holdover time has not been exceeded.

9 NO TAKE-OFF permitted with tailwind component.

10 Utilize the information in Part B to determine the crosswind

limits associated with runway conditions. (Contaminated Crosswind limits are reduced by 1KT/METRE that the runway cleared width is less than 45M).

11 Do not use an intersection takeoff point, use full runway

length. 12 Calculate RTOM using the corrections given in the QRH

Performance Dispatch section. Remember to apply the corrections to the DRY 27K (or 24K if limiting) RTOM figures.

13 Vspeeds should be determined from the Performance Dispatch

section of the QRH. Rotation should be made at the correct speed using normal rate to the normal attitude.

14 Do not use Assumed Temperature for thrust reduction. 15 Bleeds Off Takeoff – Wing anti-ice is not available to the right

wing.



Do not select wing anti-ice ON. TYPE II or IV fluid must be used. TYPE I is NOT permitted except for NEI.

1.5 RUNWAY CONDITION REPORTS Runway condition is reported to crews as follows; Dry Runway A dry runway is one which is neither wet nor contaminated, and includes those paved runways which have been specially prepared with grooves or porous pavement and maintained to retain, effectively dry braking action even when moisture is present. Damp Runway A runway is considered damp when the surface is not dry, but when the moisture on it does not give it a shiny appearance. Wet Runway A runway is considered wet when the runway surface is covered with water, or equivalent, less than specified for Contaminated Runway or when sufficient moisture on the runway surface to cause it to appear reflective, but without significant areas of standing water. Contaminated Runway A runway is considered to be contaminated when more than 25% of the runway surface area (whether in isolated areas or not) within the required length and width being used is covered by the following:



1) Surface water more than 3mm (0.125in) deep, or by slush,

or loose snow, or equivalent to more than 3mm (0.125in) of water - see below

2) Snow which has been compressed into a solid mass which

resists further compression and will hold together or break into lumps if picked up (compacted snow); or

3) Ice, including wet ice.

The minimum runway cleared width for B737-Ng operations is 30m.

Banks at thirty meters should not exceed approximately 20cms. As runway cleared widths increase, the height of snow banks may be increased proportionally at the Captain’s discretion. Captains will always exercise good judgment when assessing requirements for a particular set of circumstances. The depth of contamination of the cleared portion of the runway will not exceed AFM limits for a given type of contamination.

Equivalent Depths (mm)

Water Slush Wet Snow Dry Snow

Specific grav. 1.00 0.85 0.30 0.10 3 3 5 15 6 6 10 30 9 9 15 45 12 12 20 60

1.6 REPORTING OF RUNWAY CONDITIONS BY ATC

The presence of water on a runway will be reported by ATC on R/T using the following descriptions:

a. DAMP - The surface shows a change of colour due to moisture



b. WET - The surface is soaked but no significant patches of standing water are visible

c. WATER PATCHES - Significant patches of standing water are visible

d. FLOODED- Extensive standing water is visible

When a runway is reported as DAMP or WET, pilots may assume that an acceptable level of runway wheel braking friction is available. When a

runway is reported as having WATER PATCHES or being FLOODED, wheel braking may be affected by aquaplaning and appropriate operational adjustments should be considered as outlined in Performance Dispatch QRH. Runways that are defined as, ‘Liable to be slippery when wet’ must be treated using the same performance tables as Slippery Runway Takeoff from the Performance Dispatch section of the QRH. See definition for Wet runway page 10.

When snow, slush or ice conditions prevail, information on runway conditions will be notified by SNOWTAM, OPMET RUNWAY STATE MESSAGE, or by R/T on request. Until a satisfactory method has been found to determine accurately and quickly the density of a contaminant on a runway, the nature of the surface covering is described using the following categories based on subjective assessment by the personnel making the inspection:

e. ICE - Water in its solid state takes many forms including sheet ice, hoar

frost and rime (assumed specific gravity 0.92)

f. DRY SNOW - A condition where snow can be blown loose, or if compacted by hand will fall apart again on release (assumes

specific gravity less than 0.35)

g. COMPACTED SNOW - Snow which has been compressed into a solid mass that resists further compression and will hold together or



break up into chunks if picked up (assumed specific gravity 0.351 to 0.50)

h. WET SNOW - A composition which, if compacted by hand,

will stick together and tend to, or does, form a snowball (assumed specific gravity greater

than 0.5)

i. SLUSH - A water saturated snow which, with a heel and toe slap-down action with the foot against the ground, will be displaced with a splatter (assumed specific gravity 1.0)

j. ASSOCIATED STANDING WATER

-Standing water produced as a result of melting contaminant in which there are no visible traces of slush or ice crystals (assumed specific gravity 1.0)

BRAKING ACTION INFORMATION

It is important to remember that the reported braking action assessment is for general guidance only. It must be remembered that the friction measuring wheel (the vehicles fifth wheel) is much narrower than an airplane tyre and that the car will drive three meters to the left and subsequently the right side of the centerline for the entire length of the runway. The average readings are then calculated. It must be assumed that for an average to be an average there must be significant patches of the runway with braking actions below the official given value. The friction test driver will normally pass any comments that he may have to the tower controller along with a graphic illustration of the three braking zones. This information (at certain airfields) may be available and requested by the crew prior to using the runway in order to build a better mental picture of the three zones.



The following braking action descriptors will be used:

a. GOOD - 0.40 and above

b. MEDIUM/GOOD - 0.39 to 0.36 c. MEDIUM – 0.35 to 0.30 d. MEDIUM/POOR – 0.29 to 0.26

e. POOR - 0.25 and below - Conditions are extremely slippery.

Landings or takeoffs should not be attempted.

No satisfactory method of assessing braking action in slush exists. Therefore, when slush is present runway reports do

not include plain language braking reports. Aquaplaning conditions should be assumed to exist whenever

depths of water or slush exceeding approximately 3mm. 1.7 IN-FLIGHT PROCEDURES The build up of ice in flight may be very rapid. Crews should continually check the surfaces of wings and airframe ensuring de-icing/anti-icing systems are switched ON. Take appropriate measures to avoid flying in areas of severe icing. Do not Hold in icing conditions with Flaps extended Following flap retraction after takeoff, it is recommended to switch wing anti-ice ON. This will help to melt any accumulations of slush or ice around the flap/slat track fairings. Failure to comply with this recommendation may result in flaps/slats failing to extend after a long cold soak at altitude. It is recommended that should a non normal flap/slat condition exist, consideration be given to operating the wing anti-ice system for a suitable period to eliminate the aforementioned factor. Engine anti-icing must be switched ON when icing conditions exist or are anticipated. If visible moisture is present and temperature (TAT) is 10 degrees



Celsius or less, the engine anti-icing must be switched ON; Unless, SAT is below (colder) than -40 degrees Celsius and climb or cruise power is set. The B737 tail plane is not de/anti-iced and neither are the gear or gear doors. They will accumulate ice during flight in icing conditions. Crews must be alert to this fact particularly when operating with limited Performance available, such as Engine Inop flight. The wing de/anti-icing system is used primarily as a de-icing system. The system is normally switched ON to remove ice buildups that have developed. When the ice has cleared, switch the wing anti-ice OFF. This method is acceptable during flight in light icing conditions. When flying in moderate or severe icing, crews should use the system as an anti-icing system. Switch the wing anti-ice ON and leave it ON until leaving the icing area. Note: Speed tape stick shaker logic is set for the remainder of flight after WAI is switched ON in flight. The following definitions apply when reporting (PIREP) icing conditions to ATC: - Trace Ice becomes perceptible. Rate of accumulation slightly greater than

rate of sublimation. It is non hazardous to aircraft without de-icing/anti-icing equipment, unless encountered for more than one hour.

Light The rate of accumulation might create a problem if flight in this

environment exceeds one hour. Occasional use of de-icing/ anti-icing equipment removes/prevents accumulation. It does not present a problem if de-icing/anti-icing equipment is used.

Moderate The rate of accumulation is such that even short encounters become

potentially hazardous and use of de-icing/anti-icing equipment, or diversion, may be necessary.

Severe The rate of accumulation is such that de-icing/anti-icing equipment

fails to reduce or control the hazard. Immediate diversion is necessary.



1.8 LANDING Depths of water or slush, exceeding approximately 3 mm (1/8”), over a considerable proportion of the length of the runway, can have an adverse effect on landing performance. Under such conditions aquaplaning is likely to occur with its attendant problems of negligible wheel-braking and loss of directional control. Moreover, once aquaplaning is established it may in certain circumstances be maintained in much lower depths of water or slush. It is important that the aircraft is landed accurately, and runway distance is not forfeited trying for a smooth landing. Indeed a positive landing will break through the water surface film and lessen the chance of aquaplaning. Touchdown speed is Vref. Reverse thrust must be selected on main wheel touchdown to take advantage of approach idle to detent reverse margins. The nose wheels should be flown onto the runway taking maximum caution not to over de-rotate the nose as this will cause structural damage. The PNF must ensure that spoilers deploy automatically on touchdown or wheel spin up. Failure of the automatic system must be rectified as quickly as possible by manual selection. On the roll out be alert for aircraft swings caused by puddles of water or isolated build ups of snow or slush. After nose wheel touchdown hold LIGHT forward control wheel pressure, this will ensure that maximum weight is applied to the main gear ensuring maximum friction is available to the tyres. It will also increase nose wheel steering effectiveness. Pushing the control wheel too far forward will effectively reduce weight on wheels, reduce available tyre friction and increase weight (pressure) to the nose gear assembly and increase stopping distance. Autobrakes must be selected for landing on contaminated runways. QRH Performance dispatch should be consulted to help select the most pertinent deceleration level. After touchdown the airplane should be brought to taxi speed as soon as possible. This will be achieved by applying manual braking overriding the autobrake setting. It must be remembered that the minimum stopping distance for landing will be achieved by maximum MANUAL braking. Taxi to stand must be accomplished with caution. Single engine taxi is not permitted when taxiway contamination exists. Flaps may be left at 15 on retraction if, slush or contaminant is suspected to have impinged on the flaps and



tracks. Anti-icing systems should be turned OFF entering the apron area in order to reduce engine speeds which are automatically increased by the EEC’s when anti-ice systems are ON. If friction co-efficient is unacceptable for taxi onto stand, negotiate with ground operations to stop in a safe area. Reverse thrust to aid stopping may be used in an emergency situation. In summary: -

• STABILISED APPROACH • TOUCHDOWN AT VREF

• FIRM TOUCHDOWN

• LAND AT THE CORRECT TOUCHDOWN POINT (DO NOT

DIP BENEATH THE GLIDESLOPES OR PAPIS – THIS WILL NOT SHORTEN THE LANDING ROLL)

• ENSURE SPEEDBRAKES DEPLOY ON TOUCHDOWN

• USE MAXIMUM REVERSE TO 60KTS (OR TO A HALT IN AN

EMERGENCY CONDITION)

• USE MAX MANUAL BRAKING TO SLOW TO TAXI SPEED BRAKING ACTION IS NOT UNIFORM – THERE MAY WELL BE PORTIONS OF RUNWAY WITH BRAKING ACTION NIL – FOR THIS REASON TAXI SPEED SHOULD BE ATTAINED AS SOON AS POSSIBLE AFTER TOUCHDOWN

1.9 OVERNIGHT CHECKS & SECURITY Whenever possible hangar the aircraft overnight, if not practical ensure that; a) All aircraft water systems are drained completely; this includes galley and drinking water containers. (Water Glycol fire extinguishers are excluded, as their contents have inherent antifreeze properties.)



b) Pitot covers, engine blanks and other covers are fitted as appropriate. c) The aircraft is chocked by fore and aft chocks on the nose and at least one main wheel. d) All doors and exits are securely closed e) Consult the Supplementary procedures SP16.10-11 in Boeing Operations manual 1. 1.10 SNOWTAMS DECODE Decode of the Eight Figure Runway State Group Added to the METAR (or SPECI) 8-Figure Group 1 2 3 4 5 6 7 8

Runway designator 1 2

The first two digits correspond to the runway designator (this is not necessarily the same runway as that in an equivalent SNOWTAM). The designator is expressed as follows:

09 -Runway 09 27- Runway 27 or Runway 27 LEFT 77- Runway 27 RIGHT

(The RIGHT runway of parallel runways has 50’ added to the designator.)

88 - All runways



99 - Repetition of last message because no new message has

been received in time for transmission Runway deposit 3

The runway deposit is indicated by the third digit as follows:

0 - Clear and dry 1 - Damp 2 - Wet or water patches 3 – Rime or frost covered (depth normally less than 1mm) 4 – Dry Snow

5 - Wet snow 6 - Slush

7 - Ice

8 - Compacted or rolled snow

9 - Frozen ruts or ridges

/ - Type of deposit not reported (far example due to runway clearence in progress)

Extent of runway contamination 4



The extent of runway contamination as indicated by the fourth digit as follows:

1 - 10% or less of runway contaminated

2 - 11% to 25% of runway contaminated



/ - Extent of runway contamination not reported (for example due to runway clearance in progress). Depth of deposit 5 6

The depth of deposit is indicated by the fifth and sixth digits as follows: 00 - less than 1 mm 01 – 1mm etc

90 - 90mm 91 - not used 92 – 10cm 93 - 15cm 94 - 20cm 95 - 25 cm

Note that the quoted depth is the mean of a number of readings or, if operationally significant, the greatest depth measured.

96 - 30 cm 97 - 35cm 96 – 40cm or more

99- Runway or runways non-operational due to snow, slush, ice, large drifts or runway clearance, but depth not reported.

// - Depth of deposit operationally not significant or not measurable



Note: If deposits of the type reported in the third digit by the code figure 3, 7, 8, and 9 are reported, the depth of deposit might not be reported and // used instead. This is to be understood as meaning that the actual depth of deposit is not measurable or as not of relevance.

Note: The depth of standing water may only be reported if an accurate and representative measurement is guaranteed

Friction coefficient or braking action

7 8 28 -Friction coefficient 0.28

Note that the mean value is transmitted or, if operationally significant, the lowest value.

35 -Friction coefficient 0.35 etc. 91 -Braking action Poor

92 -Braking action Medium/Poor 93 -Braking action Medium

94 -Braking action Medium/Good 95 -Braking action Good

99 -Figures unreliable (e.g. If equipment has been used that does not measure satisfactorily in slush or loose snow).

// - Braking Action not reported: Runway not operational: Aerodrome closed.

Notes:

CLRD – If contamination conditions on all runways cease to exist, a group consisting of the figures 88, the abbreviation CLRD, and the braking action is sent. e.g. 88CLRD95 – All runways cleared, B.A good



If contamination conditions on a single runway cease to exist, a group consisting of the runway designator, the abbreviation CLRD, and the braking action is sent. e.g. 24CLRD95 – Runway 24 cleared, B.A good It should be noted that runways can only be inspected as frequently as conditions permit, so a re-issue of a previous report does not mean that the runway has been inspected again

1.11 DE-ICING FLUIDS. The three main types of de-icing/anti-icing fluids are AEA (Association of European Airlines) Type I (unthickened) which have a high glycol content and a low viscosity, Type II (thickened) which has a minimum glycol content of about 50% and Type IV which has a lower viscosity than types I or II. Type I fluids have good de-icing properties but provide only limited protection against re-freezing whereas Type II fluids have a good de-icing performance as well as providing additional protection against subsequent accretions and refreezing. Type IV fluids have a particularly low viscosity which offer increased holdover times in most conditions and are coloured to make application easier to monitor. However Type IV fluids have higher shear speeds than high viscosity fluids and some aircraft manufacturers may impose general or specific conditions on the use of Type IV. A Commander must always know what type of fluid is being used to de-ice his aircraft and ensure that the holdover times appropriate to that fluid are known and properly observed. De-icing of aircraft Ryanair has agreed that the Ground Handling agent may “early de-ice” over night aircraft in conditions where early morning frost etc. will be an obvious hazard. The agent uses a company checklist to determine whether early de-icing is appropriate and is required to ensure that either the aircraft commander or the responsible engineer is subsequently given details of the type of fluid applied and the time of application so that proper holdover times can be calculated. Finally, an aircraft commander must call for his aircraft to be de-iced whenever he thinks it necessary. Whether the de-icing takes place on stand, on a remote de-icing stand or via a remote de-icing rig, the commander may trust a de-icing



crew to do their job properly, although overall responsibility remains (as always) with the commander. Whenever or wherever an aircraft is de-iced, the procedure is only valid if the commander knows the fluid type applied, the mix of fluids and the appropriate application time and that information is written into and signed for in the airplane tech log. At STN, engineers are available to carry out all pre-flight checks which will include a check as to whether the aircraft requires de-icing. Where a commander decides he wants his aircraft de-iced, these engineers should supervise the process, ensure the necessary fluid application time details are recorded in the technical Log and carry out tactile checks when they are needed. At all other airfields, contracted ground handlers are available to complete the de-icing process. The pre-flight walk around will be completed by the crew as normal, and the Captain will request de-icing as necessary. The de-icing crew should not need supervision but they must provide fluid application time details to the commander and if they are to carry out a tactile check after a de-icing, they must have been trained to carry out the procedure. In all the cases listed above “someone” has to fill in and sign the appropriate Technical log de-icing box. That “someone’ can be an engineer or the aircraft captain but in each case the type of de-icing fluid used, the mix of fluids and the start and finish times of the applications must be recorded and signed for. This is so there is a written record to support any subsequent holdover time calculation and so that engineering personnel know when an aircraft requires a special inspection for de-icing fluid residue. This is in reference to the Boeing directive regarding tail plane vibration. Refer to Boeing Operations Manual Volume 1 – Bulletins. The above outlines the system as it exists but it is worth remembering that in the final analysis, everything with regard to the de-icing of an aircraft is the responsibility of the aircraft Captain. The Captain must ensure that his aircraft is properly de-iced in circumstances where it is appropriate, that required tactile checks have been carried out, that the technical log is signed off correctly and that the aircraft does not depart if any part of the necessary procedure has not been completed to the letter. Type IV de-icing fluid Increasingly, Type IV de-icing fluid is available at European destinations and at some airfields it is now the only de-icing on offer. Essentially, Type IV fluid is a

RYANAIR WINTER OPERATIONS & PROCEDURES Revision 1 - Sept 01st 2002


1.13 COLD WEATHER ALTIMETER CORRECTION Current industry pressure altimeters are subject to Temperature Error. The B737-Ng altimetry system is no exception to this well known phenomenon. Crews must be aware that when making descents and approaches to airfields where temperatures are below +15 degrees C that ALL altimeters on board will overread. The colder the reported OAT, the more significant the error. The error may place the airplane below the required path and below MDA or DA. It is absolutely necessary when conducting cold weather approaches to refer to the table provided on the reverse of the glare shield checklist and corrections to MSA, MEA and IF Approach profiles made. These corrections should also be applied to FMC altitudes.

winter ops 800

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