Flight Planning

Before boarding an aircraft, a navigator must thoroughly plan the flight. A well-planned flight provides a professional atmosphere, enhancing safety and accomplishment of flight objectives. Also, adequate flight planning prior to flight can avoid unnecessary in-flight problems. This category describes the navigator’s flight planning. It begins with a discussion of air traffic control (ATC) systems, followed by a brief description of publications, with which a professional navigator should be familiar. All phases of ground planning are discussed, from chart selection to arrival study.

Air Traffic Control (ATC) System

Most nations of the world today have established airspace, air traffic units, and air traffic services to promote a safe, orderly, and expeditious flow of traffic. Furthermore, in the interest of standardization, many nations are establishing systems according to the standards and recommended practices adopted by the International Civil Aviation Organization (ICAO). Navigators must understand what these air traffic services are and how they can be used.

• Air Traffic Service—a general term referring to any of the following services:

• Air Traffic Control (ATC)—a service provided by ground agencies to prevent collisions and to expedite and maintain an orderly flow of traffic. ATC includes such services as area and en route control, approach control, and tower control. It is used primarily under instrument flight rules (IFR).
• Advisory Service—provided to give air information that is useful for the safe and effective conduct of flight. This service is usually associated with the visual flight rules (VFR) environment and includes such services as weather conditions, location of known traffic, status of navigational aids (NAVAID), and status of airports and facilities.
• Alerting Service—a service provided to notify applicable organizations regarding aircraft in need of search and rescue aid and to assist such organizations as required.
• Airspace—when it has been determined that air traffic services are to be provided, portions of the airspace are designed in relation to the air traffic services that are required. Consult Flight Information Publication (FLIP) for an in-depth explanation of airspace.
• Air Traffic Service Units—provide the air traffic service within defined airspace.
• Air Route Traffic Control Centers (ARTCC)— provides ATC to IFR flights within controlled airspace.
• Approach Control—provides ATC to aircraft arriving at or departing from one or more airports.
• Airport Control Tower—provides ATC service for airport traffic.
• Flight Service Station (FSS)—operated by the Federal Aviation Administration (FAA) to provide flight assistance service.
• International Civil Aviation Organization (ICAO)—establishes international rules for ATC, the ICAO was formed in April 1947. ICAO is affiliated with the United Nations as a specialized international body dealing with aviation matters. The member states (refer to flight information publications (FLIP) General Planning (GP)) of the ICAO) subscribe to ICAO rules and procedures. These rules and procedures are used except for national deviations, which are usually filed with ICAO. Since standardization in ICAO is based upon the same technical principles and policies which are in actual effect in the continental United States (CONUS), American airmen can fly all major routes following the same general rules of the air, and governed by the same traffic control service with which they are familiar at home.
• Federal Aviation Administration (FAA)— the United States is a member of ICAO and follows ICAO standards. Deviations from ICAO standards are filed with ICAO. The FAA is responsible for air traffic services in the United States and its possessions according to the Federal Aviation Act of 1958, which consolidated all air traffic regulatory agencies under the control of the FAA. Some of the responsibilities of the FAA include:
  1. Operates the ATC system within the United States airspace.
  2. Establishes and ensures compliance with Title 14 of the Code of Federal Regulations (14 CFR), which is binding on the entire aviation community.
  3. Issues certificates to aircrew members, maintenance personnel, and control tower operators.
  4. Investigates aircraft accidents.
  5. Maintains communication stations and conducts flight checks on NAVAIDs.

Flight Planning Publications and Charts

Flight Information Publications (FLIP)

Complete aeronautical information concerning air traffic systems is published in FLIP. Published by the National Geo-Spatial Intelligence Agency (NGA), FLIP are divided into three phases of flight: planning, en route operations, and terminal operations. The en route and terminal phase publications have been divided into the following areas:

1. CONUS;
2. Alaska;
3. Canada and North Atlantic;
4. Caribbean and South America;
5. Europe, North Africa, and Middle East;
6. Africa;
7. Pacific, Australasia, and Antarctica; and
8. Eastern Europe and Asia.

General Planning (GP)

This document is revised every 32 weeks with planning change notices (PCN) issued at the 16-week midpoint. Urgent change notices (UCN) are issued as required. The FLIP GP document contains information that is applicable worldwide. It is supplemented by the information published in seven Area Publication Sections.

Area Planning (AP/1, 2, and 3)

Located behind GP in the FLIP Planning document binder, these publications contain planning and procedure information for a specific geographical area. Area Planning Documents 1, 2, and 3 are respectively North and South America, Europe- Africa-Middle East, and Pacific-Australasia-Antarctica.

Area Planning (AP/1A, 2A, and 3A)

Located behind their respective Area Planning documents, these publications contain a tabulation of all prohibited, restricted, danger, warning, and alert areas. In addition, they contain intensive student jet training areas, military training areas, and known parachute jumping areas within their specific geographical area.

Area Planning (AP/1B)

Located behind AP/1A in the FLIP Planning document, AP/1B contains information relative to military training routes in North and South America, including IFR and VFR military training routes.

Planning Change Notices (PCN)

Planning change notices (PCN) are in textual form and are used to update the FLIP Planning document.

Flight Information Handbook (FIH)

The fight informaton handbook (FIH) contains information for in-flight use. Sections include emergency procedures, national and international flight data and procedures, meteorological information, conversion tables and frequency pairings, standard time signals, and FLIP/Notices to Airmen (NOTAM) abbreviations and codes.

FLIP En Route Charts

Charts portray airway systems, radio aids to navigation, airports, airspace divisions, and other aeronautical data for IFR operations. FLIP En Route Charts are divided into high altitude (l8,000 feet mean sea level (MSL) through FL450) for use in the jet route system, and low altitude (1,200 feet above the surface up to but not including 18,000 feet MSL) for use in the airway systems. Packets of low and high altitude charts are available for each geographic area: CONUS; Alaska; Canada and North Atlantic; Caribbean and South America; Europe, North Africa, and Middle East; Africa; Pacific, Australasia, and Antarctica; and Eastern Europe and Asia.

FLIP En Route Supplements

A FLIP En Route Supplement is published for each geographical areas. Each supplement contains an airport or facility directory, en route procedures, special notices, and other textual data required to support FLIP En Route Charts. In the United States, there are two supplements. One supplement is designed for IFR operations and contains IFR airport and facility directory, special notices, and procedures required to support the FLIP En Route and Area Charts. The other supplement is designed for VFR operations and contains a listing of selected VFR airports with sketches and an IFR or VFR city and airport cross-reference listing. In all other FLIP areas, airport sketches are published for a limited number of selected airports and are provided with a separate section of the FLIP En Route Supplement. Airport sketch details include airport identification, city name, distance, direction, and elevation, as well as a diagram of each airport.

Area and Terminal Area Charts

These charts are large-scale graphics of selected terminal areas. In the United States, area charts are provided primarily as area enlargements; in foreign areas, the terminal area charts are published primarily to provide arrival and departure routings. The area and terminal charts are printed on the same size sheet as the FLIP En Route Charts (that is, the terminal or area sheet contains several terminal or area charts) and are distributed with the en route FLIP.

Approaches and Departure Procedures

FLIP terminal instrument approach procedures and departure procedures (DP) plates are divided into low altitude approaches (approaches initiated below 18,000 feet MSL), and high altitude approaches (approaches initiated normally at or above 18,000 feet MSL, such as high performance aircraft). Each instrument approach procedure shows an airport sketch, with additional data if necessary, for an approach under IFR conditions.

Terminal Change Notices (TCN)

Terminal Change Notices (TCNs) contain revisions to approach procedures and are published normally at the midpoint of the FLIP terminal booklets. The changes may be in textual or graphic form. In the United States, area TCNs revise only the low altitude approaches; however, in the Europe, North Africa, Middle East area, and Pacific, Australasia, and Antarctica areas, TCNs revise both low and high altitude approaches. In the other four FLIP areas, TCNs are not published and Notice to Airman (NOTAM) must be consulted for changes to approach procedures.

Standard Terminal Arrival Route (STAR)

Standard Terminal Arrival Route (STARs) contain preplanned IFR ATC arrival routes and are published in graphic and/or textual form. STARs provide transition from the en route structure to a fix or point from which an approach can be made. In Alaska, Pacific, Australasia, and Antarctica areas, STAR information is contained in the FLIP terminal booklets. In the United States, STARs are published in a bound booklet with civilian DPs.

Notice to Airman (NOTAM)

A NOTAM is a message requiring expeditious and wide dissemination by telecommunication means. NOTAMs provide information that is essential to all personnel concerned with flight operations. NOTAM information is normally in the form of abbreviations or a NOTAM code. The FIH contains an alphabetical list of these abbreviations.

Flight Planning

In the air, there is little time for lengthy processes of reasoning. Decisions must be made quickly and accurately; therefore, careful planning is essential to any flight. A smooth, successful flight requires a careful step-by-step plan that can be followed from takeoff to landing.

Route Determination

When planning a route to be flown, many factors enter into consideration. The route may be dictated by operational requirements of the flight; it may be a preplanned route, or the navigator may have the prerogative of selecting the route to be flown. In any case, definite factors affect route selection and the navigator must be aware of them.

In most cases, a direct route is usually best because it conserves both time and fuel. Such things as airways, routing, high terrain, and bad weather, however, can affect this. The direction of prevailing winds can affect route selection, because the proper use of a jet stream often decreases total flying time, even though a direct route is not flown.

Chart Selection

Once a route is established, navigation charts appropriate to the intended flightpath should be selected. Correct selection depends on distance to be flown, airspeeds, methods of navigation, and chart accuracy.

Total Distance to Fly

A great circle is the shortest distance between two points. Considerable distance can be saved by flying a great circle course, particularly on long-range flights in polar latitudes. A straight line on a gnomonic chart represents a great circle course. One way to flight plan a great circle course is to plot the entire route on a gnomonic chart, then transfer coordinates to charts more suitable for navigation, such as a Transverse Mercator. Select coordinates at intervals of approximately 300 nautical miles (NM). Once the route is plotted on the navigational chart, record true courses and distances for each leg of the flight on the flight plan.

Chart and Methods of Navigation

The method of navigation is determined by flight requirements and the route/area that is used. Select charts for the flight that are best suited to the navigational techniques chosen. For example, radar flights require charts with representative terrain and cultural returns for precision fixing and grid flights require charts with a grid overlay. Charts produced by NGA are shown in Figure 2-1.

Figure 2-1. National Geo-Spatial Intelligence Agency charts.

Scale

The scale of charts used for navigation varies inversely with the speed of the aircraft. For example, Jet Navigation Charts (JNC) have a small scale and contain features appropriate for high speed navigation. Navigation at slower speeds requires large scale charts providing more detailed coverage.

NOTAMs

Interim aeronautical flight information changes are disseminated by NOTAMs until the change is provided in all pertinent FLIPs. NOTAMs also provide the most current information on restrictions to flight, reliability of airport facilities and services, en route hazards, radio aids, etc.

Airways

Types and Use of Airways

Airways are corridors established by a national government within its airspace to facilitate the navigation and control of air traffic under IFR conditions. Usually, an airway is 10 statute miles wide and follows a route over the ground defined by radio NAVAIDs.

Generally, there are many different airways within a country as evidenced by those established in the United States. In the United States, as well as in other countries, there are two sets of airways (one for low altitudes and one for high altitudes.) To distinguish one airway from another, each has its own designator, such as V (low altitude) and J (high altitude). These designators simplify the preparation of a flight plan and improve the communication between aircrews and air traffic controllers.

Alternate Airfield

An alternate airfield is where an aircraft intends to land if weather conditions prevent landing at a scheduled destination. Occasionally, an airfield may also be identified as an alternate for takeoff purposes. This procedure is at the direction of company procedures and operations specifications that authorize the use of lower minimums for takeoff than for landing.

Emergency Airfields

During flight planning, select certain airfields along the planned flight route as possible emergency landing areas and then annotate these airfields on the charts for quick reference. Consider the following factors when selecting an emergency airfield: type of aircraft, weather conditions, runway length, runway weight-bearing capacity, runway lighting, and radio NAVAIDs. The NOTAMs for these airfields should be checked prior to flight.

Highest Obstruction

After the route has been determined, the navigator should study the area surrounding the planned route and annotate the highest obstruction (terrain or cultural). The distance within which the highest obstruction is annotated is in accordance with governing or local directives. The highest obstruction is taken into consideration when determining the minimum en route altitude (MEA) and in emergency procedures discussion.

Special Use Airspace

When determining the flight planned route, the locations of special use airspace has to be considered. The best way to find the locations of the areas is by checking an en route chart. After the route is determined, any special use airspace that may be close enough to the route of flight to cause concern (as per governing directives) should be annotated on the chart with pertinent information. Annotate time and days of operation, effective altitudes, and any restriction applicable to that area. These areas, when annotated on the chart, assist the navigator with in-flight changes and prevent planning a route of flight that cannot be flown.

Flight Plans

IFR and VFR Flight Plans

Flight plans are documents filed by pilots, or a Flight Dispatcher with the local Civil Aviation Authority (e.g., FAA in the United States), prior to departure. [Figure 2-2] They generally include basic information, such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether IFR or VFR), pilot’s name, and number of people onboard. In most countries, flight plans are required for flights under IFR. Under VFR, they are optional unless crossing national borders; however, they are highly recommended, especially when flying over inhospitable areas, such as water, as they provide a way of alerting rescuers if the flight is overdue. For IFR flights, flight plans are used by ATC to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Figure 2-2. FAA Flight Plan Form 7233-1 (8-82).

International Flight Plans

Flight plans are required for all flights into international and foreign airspace. The standard flight plan form is the FAA Form 7233-4, available at most U.S. Flight Service Stations (FSSs). [Figure 2-3] Flight plans must be transmitted to and should be received by ATC authorities in each ATC Region to be entered at least 2 hours prior to entry, unless otherwise stated in the various country requirements. It is extremely important that, when filing flight plans in countries outside the U.S., inquiry be made by the pilot as to the method used for subsequent transmission of flight plan information to pertinent en route and destination points and of the approximate total elapsed time applicable to such transmissions.

Figure 2-3. FAA Form 7233-4, International Flight Plan (7-93).

En Route Fuel

En route fuel is determined with a fuel graph, such as the one depicted in Figure 2-4. Each type aircraft has a series of fuel graphs based on: aircraft gross weight, pressure or density altitude, true airspeed (TAS) or Mach number and, on some aircraft, the aerodynamic drag of external stores. En route fuel is computed in a manner that takes into account the worst fuel consumption situation, such as the lowest cruise altitude and highest airspeed. Most fuel graphs are designed for standard day conditions, so temperature deviation has to be considered. En route fuel can be calculated from the start descent point or initial approach fix (IAF).

Figure 2-4. Fuel planning graph. [click image to enlarge]

Fuel Reserve

Fuel reserve is the quantity of fuel carried in excess of flight requirements if the flight is completed as planned.

En Route Plus Reserve

Add en route time and reserve time together to obtain the en route plus reserve time.

Alternate Fuel

The fuel to the alternate is based on the fuel flow for the gross weight of the aircraft at destination, TAS, and altitude flown to the alternate. Some flight manuals include graphs designed for computing fuel to the alternate, but the fuel can also be computed by adding the time to the alternate and to the en route time. This time is then used to extract the total fuel required from takeoff to alternate. En route fuel is then subtracted from this to obtain the fuel to the alternate. A standard fuel amount may be added to allow for a missed approach at the original destination.

Holding Fuel

Adverse weather, air traffic, or aircraft malfunction in the terminal area may force the aircraft to hold in the local area for a period of time before landing. The amount of holding fuel is based on any planned delays according to applicable directives.

Approach and Landing Fuel

Approach and landing fuel is the fuel required from the terminal fix to the runway. This is computed for a prescribed amount of time (usually 15 minutes). The amount of fuel needed for approach and landing varies with the aircraft.

Total Takeoff or Flaps Up Fuel

Total takeoff, or flaps up, is the cumulative total fuel from takeoff or flaps up that is required for en route, reserve, alternate, holding, and approach and landing.

Taxi and Runup Fuel

Taxi and runup fuel is the fuel needed for taxiing, engine runup, and acceleration to takeoff speed. It is usually a predetermined value for each type of aircraft.

Required Ramp Fuel

Required ramp fuel is the amount of fuel required at engine start to complete the flight.

Actual Ramp Fuel

Actual ramp fuel is the fuel onboard prior to engine start.

Unidentified Extra Fuel

Additional fuel over and above that required by the flight plan is referred to as unidentified extra fuel. It is the difference between required ramp fuel and actual ramp fuel.

Burnoff Fuel

Burnoff is the planned amount of fuel to be used after takeoff. This value subtracted from takeoff gross weight is equal to the approximate aircraft gross weight at landing.

Range Control Graph

The range control graph portrays planned, minimum, and actual fuel consumption. [Figure 2-5] It is used to flight plan fuel consumption and serves as an in-flight worksheet for comparing actual and planned fuel consumption. The range control graph can be constructed with information taken from a completed flight plan, such as Figure 2-2 and the applicable fuel planning graph in Figure 2-4. After calculating the required fuel at checkpoints along the route, the fuel remaining (vertical) is plotted against time remaining (horizontal). The planned fuel consumption is then plotted on the graph along with the minimum required fuel line. In-flight fuel readings are taken periodically and plotted on the graph to determine the fuel consumption in relation to that planned.

Figure 2-5. Range control graph.Figure 2-5. Range control graph (continued).

The planned line is determined by calculating the fuel remaining and time remaining at predetermined points in the flight and then plotting these points on the graph and connecting them with a line. The minimum line is determined by adding up all fuel required as a minimum at the destination (reserve, alternate, approach, etc.) and plotting it on the zero time remaining line. The difference between the minimum fuel required and the planned fuel on the zero time remaining line is then plotted below each of the predetermined fuel remaining points on the planned line. The points are connected with a line that represents the minimum required fuel line. This line is used to determine whether or not to continue the flight.

In-flight fuel readings are obtained and plotted against time remaining to determine fuel status. These plotted points are then connected with a dotted line that represents the actual fuel consumption. The trend of the in-flight fuel readings indicates actual fuel consumption and is used to make flight decisions with regard to fuel.

Equal Time Point (ETP)

The equal time point (ETP) is that point along the route (normally one with an extended overwater leg) from which it takes the same amount of time to return to departure (or the last suitable airfield prior to beginning the overwater leg of the flight) as it would to continue to destination (or the first suitable airfield for landing). [Figure 2-6] The ETP is not necessarily the midpoint in time from departure to destination. Its location is somewhere near the midpoint of the route (between suitable airfields), and it is dependent upon the wind factors.

Figure 2-6. Equal time point.

A wind factor (WF) is a headwind or tailwind component, computed at planned altitude between suitable airfields by comparing the average groundspeed (GS) to the average TAS. To do this, algebraically subtract the TAS from the GS. A WF with a negative value is a headwind; positive is a tailwind. When computing ETP, obtain a WF for each half of the route. Wind factors may play a major role in determining whether or not a destination can be reached. The overall or total wind factor (TFW) is the average of WF₁ and WF₂ and is computed using the formula (WF₁ + WF₂) divided by 2. An ETP is computed using the following formula:

Total Distance = T
(WF₂ – WF₁) + (2X TAS) (60 min)

Total distance is the distance in NMs from the last suitable airfield to the first suitable airfield, measured along the route of flight. WF₂ and WF₁ are wind factors for the second and first halves of the route segment, respectively. T is the time remaining in minutes from the ETP to the first suitable airfield. This time can be converted to distance by applying the GS for the second half of the route segment. The distance can then be measured uptrack and the ETP plotted on the chart. The time should be plotted on the range control graph with a vertical line that crosses both the planned and minimum lines. If the first suitable airfield is not the planned landing airfield, then the time should be added between the first suitable airfield and the landing airfield to determine the ETP.

Endurance

Endurance is the length of time an aircraft can remain airborne, not including minimum required fuel. Endurance can be computed by taking the last plotted fuel reading and following a line parallel to the fuel remaining lines in the direction of increasing time remaining until intercepting the minimum line. This point and its corresponding time remaining represent the endurance at the time of the fuel reading that is being used. Endurance is critical in making in-flight diversion decisions.