Flight plans are documents filed by a pilot or flight dispatcher with the
local Civil Aviation Authority prior to departure which indicate the plane's
planned route or flight path. Flight plan format is specified in the ICAO Doc
4444. 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, the pilot's information, number of people on board
and information about the aircraft itself. In most countries, flight plans
are required for flights under IFR, but may be optional for flying VFR unless
crossing international borders. Flight plans 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. In the United States and
Canada, when an aircraft is crossing the Air Defense Identification Zone, either
an IFR or a special type of VFR flight plan called a DVFR flight plan must be
filed. For IFR flights, flight plans are used by air traffic control to initiate
tracking and routing services. For VFR flights, their only purpose is to
provide needed information should search and rescue operations be required, or
for use by air traffic control when flying in a "Special Flight Rules Area".
Route or flight paths Routing types used in flight planning
are: airway, navaid and direct. A route may be composed of segments of different
routing types. For example, a route from Chicago to Rome may include airway
routing over the U.S. and Europe, but direct routing over the Atlantic Ocean.
= Airway or flight path= Airway routing occurs along pre-defined
pathways called flight paths. Airways can be thought of as three-dimensional
highways for aircraft. In most land areas of the world, aircraft are
required to fly airways between the departure and destination airports. The
rules governing airway routing cover altitude, airspeed, and requirements for
entering and leaving the airway. Most airways are eight nautical miles wide,
and the airway flight levels keep aircraft separated by at least 1000
vertical feet from aircraft on the flight level above and below. Airways
usually intersect at Navaids, which designate the allowed points for
changing from one airway to another. Airways have names consisting of one or
more letters followed by one or more digits.
The airway structure is divided into high and low altitudes. The low altitude
airways in the U.S. which can be navigated using VOR Navaids have names
that start with the letter V, and are therefore called Victor Airways. They
cover altitudes from approximately 1200 feet above ground level to 17,999 feet
above mean sea level. T routes are low altitude RNAV only routes which may or
may not utilize VOR NAVAIDS. The high altitude airways in the U.S. have names
that start with the letter J and are called Jet Routes, or Q for Q routes. Q
routes in the U.S. are RNAV only high altitude airways, whereas J routes use
VOR NAVAID's the same way V routes do. J & Q routes run from 18,000 feet to
45,000 feet. The altitude separating the low and high airway structures varies
from country to country. For example, it is 19,500 feet in Switzerland, and
25,500 feet in Egypt. = Navaid=
Navaid routing occurs between Navaids which are not always connected by
airways. Navaid routing is typically only allowed in the continental U.S. If
a flight plan specifies Navaid routing between two Navaids which are connected
via an airway, the rules for that particular airway must be followed as if
the aircraft was flying Airway routing between those two Navaids. Allowable
altitudes are covered in Flight Levels. = Direct=
Direct routing occurs when one or both of the route segment endpoints are at a
latitude/longitude which is not located at a Navaid. Some flight planning
organizations specify that checkpoints generated for a Direct route be a
limited distance apart, or limited by time to fly between the checkpoints.
SIDs and STARs SIDs and STARs are procedures and
checkpoints used to enter and leave the airway system by aircraft operating on
IFR flight plans. There is a defined transition point at which an airway and
a SID or STAR intersect. A SID, or Standard Instrument Departure,
defines a pathway out of an airport and onto the airway structure. A SID is
sometimes called a Departure Procedure. SIDs are unique to the associated
airport. A STAR, or Standard Terminal Arrival
Route, defines a pathway into an airport from the airway structure. STARs can be
associated with more than one arrival airport, which can occur when two or
more airports are in proximity. Special use airspace
In general, flight planners are expected to avoid areas called Special Use
Airspace when planning a flight. In the United States, there are several types
of SUA, including Restricted, Warning, Prohibited, Alert, and Military
Operations Area. Examples of Special Use Airspace include a region around the
White House in Washington, D.C., and the country of Cuba. Government and military
aircraft may have different requirements for particular SUA areas, or may be able
to acquire special clearances to traverse through these areas.
Flight levels Flight levels are used by air traffic
controllers to simplify the vertical separation of aircraft and one exists
every 1000 feet relative to an agreed pressure level. Above a transitional
altitude, which varies from country to country, the worldwide arbitrary
pressure datum of 1013.25 millibar or the equivalent setting of 29.92 inches
of mercury is entered into the altimeter and altitude is then referred to as a
flight level. The altimeter reading is converted to a flight level by removing
the trailing two zeros: for example, 29000 feet becomes FL290. When the
pressure at sea level is by chance the international standard then the flight
level is also the altitude. To avoid confusion, below the transition
altitude, height is referred to as a numeric altitude, for example 'descend
5000 feet' and above the transition altitude, 'climb flight level 250'.
Airways have a set of associated standardized flight levels which must be
used when on the airway. On a bi-directional airway, each direction
has its own set of flight levels. A valid flight plan must include a legal
flight level at which the aircraft will travel the airway. A change in airway
may require a change in flight level. In the USA and Canada, for eastbound IFR
flights, the flight plan must list an "odd" flight level in 2000 foot
increments starting at FL190; Westbound IFR flights must list an "even" flight
level in 2000 foot increments starting at FL180. However, Air Traffic Control
may assign any flight level at any time if traffic situations merit a change in
altitude. Aircraft efficiency increases with
height. Burning fuel decreases the weight of an aircraft which may then
choose to increase its flight level to further improve fuel consumption. For
example, an aircraft may be able to reach FL290 early in a flight, but step
climb to FL370 later in the route after weight has decreased due to fuel burn
off. RVSM
Alternate airports Part of flight planning often involves
the identification of one or more airports which can be flown to in case
of unexpected conditions at the destination airport. The planning
process must be careful to include only alternate airports which can be reached
with the anticipated fuel load and total aircraft weight and that have
capabilities necessary to handle the type of aircraft being flown.
In Canada, unlike the United States, unless specifically exempted by a
company Operating Certificate, IFR flight plans require an alternate
airport, regardless of the forecast destination weather. In order to be
considered as a legally valid alternate, the airport must be forecast to be at or
above certain weather minima at the estimated time of arrival. The minimum
weather conditions vary based on the type of approach(es) available at the
alternate airport, and may be found in the General section of the Canada Air
Pilot. Fuel
Aircraft manufacturers are responsible for generating flight performance data
which flight planners use to estimate fuel needs for a particular flight. The
fuel burn rate is based on specific throttle settings for climbing and
cruising. The planner uses the projected weather and aircraft weight as inputs to
the flight performance data to estimate the necessary fuel to reach the
destination. The fuel burn is usually given as the weight of the fuel instead
of the volume because aircraft weight is critical.
In addition to standard fuel needs, some organizations require that a flight plan
include reserve fuel if certain conditions are met. For example, an
over-water flight of longer than a specific duration may require the flight
plan to include reserve fuel. The reserve fuel may be planned as extra
which is left over on the aircraft at the destination, or it may be assumed to
be burned during flight. In case of an in-flight emergency it may
be necessary to determine whether it is quicker to divert to the alternate
airfield or continue to the destination. This can be calculated according to the
formula as follows: where C is the distance from the
Critical Point to the destination, D the distance between the destination and the
alternate airfield, O is the groundspeed, A is the airspeed, θ = Φ
+/- d, and d is the drift. Flight plan timeline
Flight plans may be submitted before departure or even after the aircraft is
in the air. However flight plans may be submitted up to 24 hours in advance
either by voice or by data link; though they are usually filled out or submitted
just several hours before departure. The minimum recommended time is 1 hour
before departure for domestic flights, and up to three hours before
international flights. This time depends on the country the aircraft is flying
out of. Other flight planning considerations
Holding over the destination or alternate airports is a required part of
some flight plans. Holding may be necessary if unexpected weather or
congestion occurs at the airport. If the flight plan calls for hold planning, the
additional fuel and hold time should appear on the flight plan.
Organized Tracks are a series of paths similar to airways which cross ocean
areas. Some organized track systems are fixed and appear on navigational charts.
Others change on a daily basis depending on weather, west or eastbound and other
factors and therefore cannot appear on printed charts over the Atlantic Ocean).
Description of flight plan blocks Domestic Flight Plan Form 7233-1,
Type: Type of flight plan. Flights may be VFR, IFR, DVFR, or a combination of
types, termed composite. Aircraft Identification: The
registration of the aircraft, usually the flight or tail number.
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. True airspeed in knots: The planned
cruise true airspeed of the aircraft in knots.
Departure Point: Usually the identifier of the airport from which the aircraft
is departing. Departure Time: Proposed and actual
times of departure. Times are Universal Time Coordinated.
Cruising Altitude: The planned cruising altitude or flight level.
Route: Proposed route of flight. The route can be made up of airways,
intersections, navaids, or possibly direct.
Destination: Point of intended landing. Typically the identifier of the
destination airport. Estimated Time Enroute: Planned elapsed
time between departure and arrival at the destination.
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. Fuel on Board: The amount of fuel on
board the aircraft, in hours and minutes of flight time.
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. Pilot's Information: Contact information
of the pilot for search and rescue purposes.
Number Onboard: Total number of people on board the aircraft.
Color of Aircraft: The color helps identify the aircraft to search and
rescue personnel. 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 A measurement of altitude above a
specific land mass. International Civil Aviation
Organization 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 responsibilities is the unique
worldwide names used to identify Navaids, Airways, airports and
countries. Knot
A unit of speed used in navigation equal to one nautical mile per hour.
Mean Sea Level The average height of the surface of the
sea for all stages of tide; used as a reference for elevations.
Nautical mile A unit of distance used in aviation
equal to approximately one minute of arc of latitude. It is defined to be 1852
metres exactly, or approximately 1.15 statute mile.
See also Flight planning
Aircraft Communications Addressing and Reporting System
Future Air Navigation System Aeronautical Telecommunication Network
Flight Service Station References
External links Electronic US Domestic Flight Planning
by Skytrex Systems - AvCaddy EFB International Flight Planning Resource
by Region International Civil Aviation
Organization Federal Aviation Administration
Aviation glossary Centennial of Flight