Flight planning is the process of producing a flight plan to describe a proposed aircraft flight. It involves two safety-critical aspects: fuel calculation, to ensure that the aircraft can safely reach the destination, and compliance with air traffic control requirements, to minimize the risk of midair collision.
In addition, flight planners normally wish to minimize flight costs through the appropriate choice of route, height, and speed, and by loading the minimum necessary fuel on board.
Air Traffic Services (ATS) use the completed flight plan for the separation of aircraft in air traffic management services, including tracking and finding lost aircraft, during search and rescue (SAR) missions.
Description of flight plan blocks (FAA)
1. Type:
Type of flight planning. Flights may be DVFR, VFR, and IFR, or a combination of types, termed composite.
2. Aircraft Identification:
The registration of the aircraft, usually the flight or tail number.
3. Aircraft Type/Special Equipment:
The type of aircraft and how it’s equipped. For example, a Mitsubishi Mu-2 equipped with an altitude-reporting transponder and GPS would use MU2/G. Equipment codes may be found in the FAA Airman’s Information Manual.
4. True airspeed in knots:
The planned cruise true airspeed of the aircraft in knots.
5. Departure Point:
Usually the identifier of the airport from which the aircraft is departing.
6. Departure Time:
Proposed and actual times of departure. Times are universally Time Coordinated.
7. Cruising Altitude:
The planned cruising altitude or flight level.
8. Route:
The proposed route of flight. The route can be made up of airways, intersections, navaids, or possibly direct.
9. Destination:
Point of intended landing. Typically the identifier of the destination airport.
10. Estimated Time Enroute:
The planned elapsed time between departure and arrival at the destination.
11. Remarks:
Any information the PIC believes is necessary to be provided to ATC. One common remark is “SSNO”, which means the PIC is unable or unwilling to accept a SID or STAR on an IFR flight.
12. Fuel on Board:
The amount of fuel on board the aircraft, in hours and minutes of flight time.
13. Alternate Airports:
Airports of intended landing as an alternate of the destination airport. May be required for an IFR flight plan if poor weather is forecast at the planned destination.
14. Pilot’s Information:
Contact information of the pilot for search and rescue purposes.
15. Number Onboard:
The total number of people on board the aircraft.
16. Color of Aircraft:
The color helps identify the aircraft to search and rescue personnel.
17. Contact Information at Destination:
Having a means of contacting the pilot is useful for tracking down an aircraft that has failed to close its flight plan and is possibly overdue or in distress.
Some terms and acronyms used in flight planning
Above Ground Level (AGL)
A measurement of elevation, or “height”, above a specific land mass (also see MSL).
International Civil Aviation Organization (ICAO)
The ICAO is the specialized agency of the United Nations with a mandate “to ensure the safe, efficient and orderly evolution of international civil aviation.”
The standards which become accepted by the ICAO member nations “cover all technical and operational aspects of international civil aviation, such as safety, personnel licensing, operation of aircraft, aerodromes, air traffic services, accident investigation, and the environment.”
A simple example of ICAO’s responsibilities is the unique worldwide names used to identify Navaids, Airways, airports, and countries.
Knot (Kt)
A unit of speed used in navigation is equal to one nautical mile per hour.
Mean Sea Level (MSL)
The average height of the surface of the sea for all stages of the tide; is used as a reference for altitude (also see AGL).
Nautical mile (NM)
A unit of distance used in aviation and maritime navigation, equal to approximately one minute of arc of latitude on a great circle. It is defined to be 1852 meters exactly or approximately 1.15 statute miles.
Route Forecast (ROFOR)
A format for reporting weather information.
Zero-Fuel Weight (ZFW)
The weight of the aircraft with crew, cargo, and passengers, but without fuel.
Know the factors that determine a flight plan or schedule
A flight planning (essentially, how to fly from A to B with a specific aircraft; on a specific day; with a given passenger, cargo and fuel load; weather, etc.) is not the same thing as a schedule (essentially, what are the published departure and arrival times).
Most large airlines view the scheduling problem as an optimization problem: maximize profit given the fleet, various airport constraints, fleet-specific O&D constraints, passenger demand, costs, etc., etc.
With changing time zones, it is easy to see that the available options are limited. For example, for US – Europe (west to east), you can either leave late in the day and fly overnight to arrive in the am or leave in the morning and arrive in the late evening.
Since the overnight flight allows business travelers to fly when they can’t otherwise be doing business, it is the preferred choice, and the airlines’ schedules reflect this. The number of eastbound flights (US to Europe) that depart in the am is smaller.
Finally, notice that airlines tend to schedule on top of each other. This is simply a matter of competing for the same demand.
Understand the reclear process
Reclear flight planning was originally designed for the airlines in cases where long-distance flights were faced with landing with less than legal fuel reserves. Using the later stages of a flight, the crew picks a reclear airport near their destination where the aircraft can land if needed.
They then reclear at a fix near that airport and recalculate fuel reserves from that point to the original destination. This technique can be used to achieve additional range. It’s particularly advantageous for larger, General Aviation (GA), but also well suited to operators of ultra-long-range equipment.
How many days in advance do airlines schedule their flights?
Airlines have a multi-department organizational structure where different departments are given schedules for minor/ major adaptations at different timelines of the process.
The schedule generation initiates approximately 9–12 months in advance for major airlines, and then this schedule is passed on to different departments to make changes on the basis of market trends.
These changes are done for 2 months from the day of operation after which it is passed on to the operations control department for the development of schedule recovery strategies and some minor adaptations to be implemented on the schedule’s day of operation.
Largely, the airlines start schedule generation 9–12 months in advance but during the planning phase, a lot of unpredictable events called uncertainties occur which need to be addressed in the schedules generated.