Obstacle Departure Procedure
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Obstacle departure procedure (ODP) is a type of departure procedure that provides obstruction clearance via the least onerous route from an airport to an appropriate en-route structure. Pilots can fly ODPs without prior clearance unless assigned a
standard instrument departure Standard instrument departure (SID) routes are published flight procedures followed by aircraft on an IFR flight plan immediately after takeoff from an airport. SIDs are one of the two types of departure procedures (DP); the other type being Ob ...
or radar vectored by
air traffic controller An Air traffic controller (ATC) is a person responsible for the coordination of traffic in their assigned airspace. Typically stationed in area control centers or control towers, they monitor the position, speed, and altitude of aircraft and c ...
s.


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ODPs may be designed using either conventional or
area navigation Area navigation (RNAV, usually pronounced as ) is a method of instrument flight rules (IFR) navigation that allows aircraft to fly along a desired flight path, rather than being restricted to routes defined by ground-based navigation beacons. ...
(RNAV) criteria. ODPS can be either graphical or textual; graphical ODPs always note "(OBSTACLE)" in the title.


Development

When an airport is being analyzed for designing an
instrument approach procedure In aviation, an instrument approach or instrument approach procedure (IAP) is a series of predetermined maneuvers for the orderly transfer of an aircraft operating under instrument flight rules from the beginning of the initial approach to a lan ...
, an obstacle departure procedure assessment is conducted first. Pass the departure end of the runway, Surveyors establish an obstacle clearance surface (OCS), which is an imaginary surface that rises at a 40:1 ratio under standard conditions, or 152ft per nautical miles. The OCS can rise more steeply if terrain or other obstacles are present. Pass the departure end of the runway at 35ft above ground, if an aircraft can maintain 48ft per nautical mile clearance above the OCS, or maintain a climb rate of 200ft per nautical mile for standard 40:1 ratio OCS, no ODP will be established. Otherwise, an ODP is included with the instrument procedure. Commonly, ODPs are developed under the assumption that the aircraft will: * Cross the departure end at least 35 feet above runway departure end elevation; * Climb to 400 feet above runway departure end elevation before turning; * Maintain climb gradient > 200 ft per nautical mile until reaching minimum
IFR In aviation, instrument flight rules (IFR) is one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other is visual flight rules (VFR). The U.S. Federal Aviation Administration's (FAA) ''Instrument Fly ...
altitude. Unlike
Standard Instrument Departure Standard instrument departure (SID) routes are published flight procedures followed by aircraft on an IFR flight plan immediately after takeoff from an airport. SIDs are one of the two types of departure procedures (DP); the other type being Ob ...
s, ODPs are generally developed for smaller airports. It is also assumed that all aircraft engines are in normal operation during the climb, as opposed to being a safeguard for twin engine planes with one engine inoperative.


References

{{Aeronautical charts Aviation publications Flight planning