PAGE: 1 Table of Contents CHAPTER 3.-... 2 3.1 NOTAM... 2 3.2 ORIGINAL DISPATCH (FLIGHT RELEASE), RE-DISPATCH, AMENDMENT... 2 3.3 WEATHER REQUIREMENTS... 3 3.3.1 DEFINITION OF WEATHER CONDITIONS... 3 3.3.2 AIRPORT WEATHER FORECASTS -APPLICATION FOR FLIGHT PLANNING... 3 3.3.3 DISPATCH OR FLIGHT RELEASE UNDER IFR OR OVER-THE-TOP... 3 3.3.4 FLIGHT RELEASE BELOW MINIMA -USING FLAG AND SUPPLEMENTAL EXTENDED OVER-WATER RULES... 4 3.3.5 DESTINATION WEATHER MINIMA... 4 3.3.6 ALTERNATE WEATHER MINIMA... 4 3.3.7 WITH NO APPROVED APPROACH... 4 3.3.8 CIRCLING APPROACH... 4 3.3.9 WEATHER DOCUMENTATION... 4 3.4 SELECTION OF ALTERNATES... 5 3.4.1 ALTERNATE AIRPORT NOMINATION AND FORECAST LANDING CONDITIONS... 5 3.4.1.1 POLITICAL CONSIDERATIONS FOR ANY ALTERNATE... 6 3.4.2 TAKE-OFF ALTERNATE... 6 3.4.3 EN-ROUTE ALTERNATE... 7 3.4.4 DESTINATION ALTERNATE... 7 3.5 AIRPLANE WEIGHT LIMITATIONS... 8 3.5.1 ESTIMATED ZERO FUEL WEIGHT MESSAGE... 8 3.5.2 DISPATCH RELEASE MAXIMUM TAKE-OFF WEIGHT (MTOW)... 8 3.5.3 MAXIMUM LANDING WEIGHT (MLW)... 8 3.5.4 LOAD SHEET... 9 3.6 CRUISE SPEEDS FOR PLANNING... 9 3.7 LANDING RUNWAY LENGTH... 9 3.8 OPERATIONS INTO ICING CONDITIONS... 9 3.9 FLIGHT PLAN FOR USE... 10 3.9.1 COMPUTER FLIGHT PLAN... 10
PAGE: 2 CHAPTER 3.- 3.1 NOTAM NOTAMS are provided by the following entities: Aero Thai within Thailand and the Aeronautical Information Publications of foreign governments in accordance with ICAO standards. Dispatchers must provide the Pilotin-command with all available information regarding airport conditions and irregularities of navigational facilities that may affect the safety of flight. This requirement is satisfied by the inclusion of NOTAMS in the Pre-flight Briefing. The latest information available or information provided on a previous flight leg may be used to satisfy this requirement. Because NOTAM information affects the judgment of both the Captain and the dispatcher, NOTAMS are considered in planning a flight. Dispatch will provide the Captain with NOTAMS and any applicable information that later becomes available. Crews operating multi-sector flights are to be given copies on departure from the first station only, and will retain them through transit stations with any updates. 3.2 Original Dispatch (Flight Release), Re-dispatch, Amendment The Company may use any regular airports, or refueling airports which are authorized for the aircraft type, as a destination airport for the purpose of original Dispatch Release. Neither the Pilot-in-Command nor the Dispatcher may allow a flight to continue to a destination airport to which it has been dispatched or released, unless the weather conditions at an alternate airport that was specified in the Dispatch Release are forecast to be at or above the alternate minimum s specified 'in the operations specifications for the airport, at the time the aircraft would arrive at the alternate airport. Where applicable, the Dispatch Release may be amended enroute to include any new or additional alternate if: The aircraft arrives at that alternate airport with the fuel reserves that apply for that flight; The alternate airport weather conditions at the estimated time of arrival are at or above the alternate airport weather minima specified in its operations specifications; and The airport that is within the fuel range of the aircraft. The original destination or alternate airport of a flight that is specified in the original Dispatch Release cannot be changed to another airport while the flight is in progress unless the other airport meets all of the requirements applicable to the original destination or alternate airports. When a Dispatch Release is amended while a flight is in progress: The Dispatcher will record the time the amendment became effective with his signature on the Dispatch Release. The PIC, if he concurs with the Dispatcher, will record the Dispatcher's name or initials and the time of the amendment on his copy of Dispatch Release and sign the amendment indicating his concurrence.
PAGE: 3 3.3 Weather Requirements 3.3.1 Definition of Weather Conditions For purposes of flight planning, the following criteria will be used CONDITION USA Ft ICAO TAF OR 50%Probability "OCNL" "BECMG" "TEMPO" 30% to 50%Probability "CHC" "PROB30" "PROB40" 10% to 20%Probability "SLGTCHC" "TEMPO" Note: Detailed weather report and forecast decoding information are given in the Jespersen route manual. SKC - Sky clear; no cumulonimbus and no clouds below 5000 ft., or below the minimum sector altitude, whichever is greater. CAVOK - Cloud and Visibility Okay. Visibility 1O km or more; no cumulonimbus and no clouds below 5000 ft., or below the minimum sector altitude, whichever is greater; no precipitation, thunderstorm, sandstorm, dust storm, shallow fog or low drifting dust, sand or snow forecast. SCT - Scattered; up to one-half the sky covered or obscured by clouds. BKN - Broken; more than one-half but less than complete sky coverage by clouds. OVC - Overcast; complete sky coverage by clouds. 3.3.2 Airport Weather Forecasts -Application for Flight Planning Weather forecasts provided by the Thai Meteorological Office, US National Weather Service, World Meteorological Organization, approved weather services of other countries, and other approved sources often contain conditional phrases such as OCNL, CHC, TEMPO, SLT CHC, or PROB. These phrases modify the main body of the forecast and indicate the probability of change in conditions during the forecast period. Flight crews and Dispatch will use the worst weather conditions listed in any report or forecast as the controlling factor for any flight movement. This makes the remarks portion of a forecast as operationally significant as the main body of the forecast. It is Company policy that the worst weather condition listed in the main body or remarks portion of the terminal forecast, as well as any weather report used, is the controlling factor in the selection of destination and alternate airports. The above policy also applies to TREND forecasts (FC). Where available, the TREND forecast overrules the airport forecast (TAF/TAFOR) for the valid period. 3.3.3 Dispatch or Flight Release under IFR or Over-the-Top All Company flights are to be conducted under IFR Rules. Dispatchers on duty may not dispatch or release a Company aircraft for operations under IFR or over-the-top unless appropriate weather conditions will be at or above the authorized minimums at the estimated time of arrival at the airport or airports to which dispatched or released.
PAGE: 4 3.3.4 Flight Release below Minima - Using Flag and Supplemental Extended Over-Water Rules A flight may be dispatched to an airport reporting below minima, if in the judgment of the Captain and the Dispatcher after reviewing weather reports or forecast or both, there is a reasonable expectancy of weather improvement to approved minima at the estimated time of arrival (ETA) provided the alternate airport will be above minimums at the estimated time of arrival at the alternate. Otherwise a delayed departure or a cancelled landing will be appropriate. 3.3.5 Destination Weather Minima When dispatch rules require that the destination airport have weather at or above landing minima weather reports or forecasts or a combination of both must indicate that weather conditions at the ETA at that airport will be at or above the published landing minima shown on the applicable approach chart considering current NOTAMS and field condition When determining forecast weather at destination where ceiling is required, it may be necessary to consider "occasional" or "chance of' conditions" as part of the basic fore-cast to ensure the forecast cloud layers (when they constitute a ceiling) at the time of arrival will be equal to or greater than the QFE value, which appears in parentheses following the DH or MD value for the instrument approach procedure, expected to be used at the time of arrival. Where there is only a requirement for visibility to conduct an approach only the visibility need be considered (refer to Definitions of Weather Conditions). Note: Metric Minima for ceiling, visibility and RVR, when in use, are not abbreviate but are shown as complete values RVR visibility values are charted only when the value is not the same as the prevailing or meteorological visibility value. When a difference occurs, the respective RVR and prevailing or meteorological visibility values are prefixed with "RVR" and "VIS". When there is no difference, the minimum is shown only once and means either RVR (if RVR is reported for that runway) or visibility if measured otherwise. 3.3.6 Alternate Weather Minima The minima in this part are for dispatch purposes only and are not to be considered as operating minima. For weather minima applicable at an airport to which a flight has actually diverted, destination airport weather minimums apply. 3.3.7 With No Approved Approach The ceiling and visibility must be adequate to permit a descent from the MEA and to approach and land under basic VFR at the ETA at that airport. 3.3.8 Circling Approach Visual maneuvering authorized with 1000 ft. and 3 miles. 3.3.9 Weather Documentation As allowed in regulations to use "weather reports or forecasts, or any combination thereof," a flight can be dispatched with a forecast only when there are no legal requirements for a current weather sequence report. Weather sequence reports are provided for flight planning when available. When destination or alternate sequence reports are not available, the flight will be dispatched using a forecast only.
PAGE: 5 Each departing flight must have the latest available weather reports or forecasts or a combination of both, appropriate to the route and altitude planned, and for airports designated in the Dispatch Release. This should include forecasts and reports of adverse weather phenomena, such as clear air turbulence, thunderstorms, and low altitude wind shear. Weather documentation provided for a previous flight leg may be used to meet the requirements if it is the latest available. This information affects the judgment of both the Captain and the Dispatcher and is, therefore, considered as a part of the Dispatch Re- lease. Station operations personnel should provide the Captain with any additional applicable weather reports or forecasts as they become available. 3.4 Selection of Alternates At least one destination alternate must be selected. The nomination and use of alternate airports which are situated in airspace where ATC may not grant priority to aircraft on diversion, or which have deficient standards of approach and landing aids, should be avoided. The alternate selected will be a regular, provisional, refueling, or alternate airport close to destination. The naming of an alternate further from destination than safely necessary increases required fuel and thereby decrease payload. Policy is to name the closest suitable alternate airport for each flight that requires an alternate. Suitability must consider the following:- a.) Actual and/or forecast weather and the reliability of the forecast. Obviously, a large high pressure area would make a forecast more reliable than rapidly moving fronts which are subject to changes of direction or speed. b.) Marginal forecast in the same weather pattern. c.) Flight time from departure to destination. The longer a flight is from destination in terms of time, the less reliable a forecast may be. d.) Approach radio aids and their status. The Captain and Dispatcher will agree to the selection of an alternate closest to the destination that meets safety requirements. Status of handling capability is not normally a determining factor at the time of original dispatch. Ground handling becomes important when the flight is approaching destination and a diversion becomes possible or probable. Short range flight dis- patches to an airport with marginal weather will make ground handling a consideration in selection of an alternate. Note: The selected take - off alternate, en-route alternate and destination alternate must be specified in the operational flight plan. 3.4.1 Alternate Airport Nomination and Forecast Landing Conditions The following criteria for forecast weather conditions are planning criteria and must be satisfied only at the planning stage. Detailed alternate requirements and the minimum weather conditions applicable to them are given in the following paragraphs. Where forecasts state a percentage probability for the occurrence of a condition, then only Prop 40%' and higher need to be taken into account when considering forecast conditions at an alternate. Airports are categorized into three groups; Takeoff Alternates, Destination Alternates and En-Route Alternates.
PAGE: 6 For any Takeoff Alternate or Destination Alternate, the forecast crosswind component must not exceed the limit for the applicable surface condition on the runway expected to be used for the landing, for the period one hour before and one hour after, the estimated time of arrival at the Takeoff or Destination alternate airport. Note: METAR winds are in degrees True. Crosswind limits are unaffected by engine status. 3.4.1.1 Political Considerations for Any Alternate When nominating an alternate, consideration must be given to political as well as operational factors. Where an alternate would not be approved under normal circumstances for political reasons, it must not be planned. After the planning stage, it will not be used except when an emergency is encountered and declared to ATC. Crews should be aware that in the case of diversion to an alternate that is not politically friendly, then the aircraft, passengers and crew may be subject to detention and a substantial fine levied against the airline. An additional vital consideration is that passengers on board may be vulnerable to punitive action by the State for political reasons if they are identified by authorities of the State when disembark due to operational reasons. These considerations apply equally to technical stops for fuel uplift. 3.4.2 Take-Off Alternate A suitable take-off alternate must be specified and documented in the operational flight plan when meteorological and/or performance considerations preclude a return to the departure aerodrome. This take-off alternate will be located within a) For two engine airplanes, one hour still air flight time at the AFM one engine inoperative cruising speed in ISA calculated on the actual take-off weight. b) For three and four engine airplanes, two hours still air flight time at the AFM one engine inoperative cruising speed in ISA calculated on the actual take-off weight. c) If the AFM does not contain a one-engine-inoperative cruising speed the speed to be used for calculation must be the remaining engine max continuous power speed. At the nominated Takeoff alternate, the weather reports or forecasts, or any combination thereof, which indicate that, during the period commencing 1 hour before and ending 1 hour after the ETA at the aerodrome, the weather conditions are at or above the applicable planning minimum. In addition the forecast conditions must be such that a successful CAT 1 ILS, or if necessary, non-precision approach, may be carried out on a runway expected to be available at the probable time of the approach. Airplane takeoff and climb performance with one engine inoperative must be considered when selecting a takeoff alternate. The airplane must be capable of climbing to a safe altitude which will permit onwards flight to the commencement of the approach at the selected takeoff alternate from the published initial approach altitude at that airport. The criteria listed are only required at the planning stage. Once flight has commenced an airplane may use any adequate airport as a takeoff alternate, which is at or above the lowest approach minima for which the crew are qualified and for which the airplane equipment required to fly the approach is serviceable.
PAGE: 7 3.4.3 En-Route Alternate During en-route, one-engine out limitations must be taken in account. (See Section 4.4.4.) When selecting an en-route alternate in accordance with fuel planning the en-route alternate weather must be suitable during the period commencing 1 hour before an ending 1 hour after the ETA at that aerodrome. 3.4.4 Destination Alternate When selecting an aerodrome as destination or alternate, the planning minimum for landing must be established for the possible approach aid available taking into account the prevailing wind direction and the serviceability conditions of the approach aid at the estimated time of arrival. At least one destination alternate must be selected for each IFR flight unless: The planned duration of the flight from take-off to landing does not exceed 6 hours; and Two separate runways are available and usable at the destination aerodrome and the appropriate weather reports or forecasts or any combination thereof indicate that, for the period commencing 1 hour before and ending 1 hour after the ETA at the destination, the ceiling will be at least 2000 ft. or circling height+ 500 ft., whichever is greater, and the visibility will be at least 5 km. When the destination is isolated and no adequate destination alternate exists fuel policy in Section 4.3.5.1 may require additional fuel for that flight. Two destination alternates must be selected when the appropriate weather reports or forecasts, or any combination thereof, indicate that during a period commencing 1 hour before and ending 1 hour after the ETA at the destination the weather conditions will be below the applicable planning minimum; or When no meteorological information is available. All required alternates must be specified in the operational flight plan. The Commander is responsible for the specification and documentation of the alternate aerodromes. Note 1: Runways on the same aerodrome are considered to be separate runways when: They are separate landing surfaces which may overlay or cross such that if one of the runways is blocked, it will not prevent the planned landing on the other runway; and Each of the landing surfaces has a separate approach procedure based on a separate aid. Note 2: An adequate aerodrome is an aerodrome, which the operator and the Authority consider to be adequate, having regard to the performance requirements applicable at the expected landing weight anticipated at the expected time of use: The aerodrome will be available and equipped with necessary ancillary services such as ATC, sufficient lighting, communications, weather reporting, navaids and emergency services; an At least one letdown aid will be available for an instrument approach (Ground radar would so qualify). Note 3: A suitable aerodrome is an adequate aerodrome with weather reports or forecasts, or any combination thereof, indicating that the weather conditions are at or above operating minimum and the aerodrome condition report indicate that a safe landing can be accomplished at the time of intended operation.
PAGE: 8 3.5 Airplane Weight Limitations Airplane loading limitations have been established to protect the airplane's structural integrity and to provide adequate performance margins under critical conditions of flight. The objective of load planning is to carry all or as much as possible of the revenue load (cargo) to the intended destination. Frequently flights are planned and operated at limiting weights lower than allowable by airplane performance due to volume limit of the cabin load, or estimated cabin loads below the capacity of the airplane. Within these limitations it is the Dispatcher's responsibility to meet the objectives stated above as economically as possible. In doing so he determines the following values: a.) Dispatch Release Maximum Take-off Weight (MTOW) b.) Maximum Landing Weight (MLW) c.) Dispatch Release Maximum Zero Fuel Weight (MZFW) d.) Minimum Fuel Required (MFR) e.) Extra fuel The Dispatcher is responsible to ensure that the MTOW and MZFW shown on the Dispatch Release do not exceed structural or performance limitations under the conditions forecast for the operations. 3.5.1 Estimated Zero Fuel Weight Message Zero Fuel Weight (ZFW) may be limited by the amount of required fuel. Whenever possible, stations are to provide Dispatch with a realistic estimate of ZFW at the latest one hour before departure. Dispatch will flight plan and compute required fuel based on the estimated ZFW without any padding to provide for last-minute changes. 3.5.2 Dispatch Release Maximum Take-off Weight (MTOW) It is the Captain's responsibility to ensure that the actual TOW does not exceed the structural or performance limitations at the time of departure. The Dispatch Release MTOW is limiting unless revised upward or downward by the Captain whenever conditions permit. An upward adjustment will only become necessary if the Captain has directed the loading of extra fuel. Frequently the MTOW will be above the CFP TOW, (and in these cases, is intended for weight and balance computations only. The MTOW must not exceed the lower of the following two computations: a.) Structural Limit given by the manufacturer in the Limitations Chapter of the relevant Airplane Flight Operations Manual, and b.) Performance-limited MTOW which is the lower of either of the following: i. Take-off performance limits which are determined from the tables in the Airport Analysis Manual, and ii. MTOW limited by MLW which is determined by adding fuel burn to the MLW. When determining performance-limited TOW the Captain and the Dispatcher are to use values for performance that they anticipate will exist at the time of take-off. 3.5.3 Maximum Landing Weight (MLW) a.) Structural Limit - To determine structural MLW, see the Limitations Chapter of the relevant Airplane Flight Operations Manual.
PAGE: 9 b.) Performance-Limit MLW - The approach and landing climb limits and the landing runway limits are determined from the tables in the Runway Analysis Manual. When determining performance-limited MLW, the Captain and the Dispatcher are to use values for performance factors that they anticipate will exist at the time of landing. (See "Landing Runway Length" below.) 3.5.4 Load Sheet The MTOW and MZFW shown on WEIGHT AND BALANCE LOADING FORM will be considered the maximum allowable weights for the flight. If take-off conditions change and the Captain direct extra fuel to be loaded, a new WEIGHT AND BALANCE LOADING FORM is NOT required for changes up to a total of 10,000 lbs. for H25B flights in take-off weight. But (both PIC and Dispatcher must record the time and sign their Dispatch Release to annotate the amendment) or a new computer flight plan will be transmitted to the PIC if required. 3.6 Cruise Speeds for Planning Computer flight plans are normally calculated on fixed Mach number or cruise speed. Flight crew will operate the airplane on LRC at all cruise levels unless otherwise specified. 3.7 Landing Runway Length If the landing runway at the destination is expected to be wet or slippery at the flight's estimated time of arrival, fifteen percent additional runway is required. Verify details using the relevant aircraft performance charts. This limitation applies for load planning purposes only and is not an operating limitation. The following is to be considered in determining applicability of the wet-slippery runway limitation: a.) Dry Runway: A dry runway may be anticipated either with scattered showers in the area, with intermit- tent drizzle of no greater-than-moderate intensity, with intermittent light rain and surface temperatures above freezing, or with light rain and surface temperatures above freezing, or with light snow and surface temperatures below (28 F) -2 C. In assuming a dry runway, all other factors affecting the condition of the landing runway should also be considered. b.) Wet-Slippery Runway: When precipitation of greater severity or intensity than that listed above is not forecast to end in sufficient time to allow the runway to dry or be cleared, or if for any other reason the runway may be slippery (with ice, slush or snow), a wet slippery runway must be anticipated. 3.8 Operations into Icing Conditions No aircraft will be dispatched into known or forecast icing conditions unless: A.) The aircraft is equipped with operational: Wing Icing Detection System, Wing Anti-icing System, Engine Anti-icing System, and B.) The alternate and destination airports have de-/anti-icing capability.
PAGE: 10 3.9 Flight Plan for Use A copy of the flight plan filed with ATC must be carried on board the airplane to the destination. When a Flight Plan is filed, the crew must be provided with a copy (or copy of telex) of the flight plan. The Dispatcher assigned with the flight will retain a copy of the same flight plan for his monitoring of flight progress. If for any reason a flight plan has not been prepared or filed with ATC, the Captain will ensure that this is accomplished promptly so as not to delay the flight departure. Under unusual circumstances at a departure station, this may require a flight crew member to prepare and file the flight plan manually and forward a copy on teletype to Dispatch if feasible. 3.9.1 Computer Flight Plan Dispatch normally prepares a Computer Flight Plan (CFP) for departures of all flights. If conditions change and the flight cannot operate as originally planned, the crew may use telephone or air-ground radio to enlist the assistance of Dispatch. Dispatch will attempt to forward a revised CFP to the departure station. Because of the nature of point-to-point communications and to avoid a delay, the crew may depart with a manual flight plan. Use of this procedure will be noted in the Dispatch Log.