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Departure Procedures

3. Design and publish a specific departure route;


4. A combination or all of the above.

e. What criteria is used to provide obstruction

clearance during departure?

1. Unless specified otherwise, required obstacle

clearance for all departures, including diverse, is

based on the pilot crossing the departure end of the

runway at least 35 feet above the departure end of

runway elevation, climbing to 400 feet above the

departure end of runway elevation before making the

initial turn, and maintaining a minimum climb

gradient of 200 feet per nautical mile (FPNM), unless

required to level off by a crossing restriction, until the

minimum IFR altitude. A greater climb gradient may

be specified in the DP to clear obstacles or to achieve

an ATC crossing restriction. If an initial turn higher

than 400 feet above the departure end of runway

elevation is specified in the DP, the turn should be

commenced at the higher altitude. If a turn is

specified at a fix, the turn must be made at that fix.

Fixes may have minimum and/or maximum crossing

altitudes that must be adhered to prior to passing the

fix. In rare instances, obstacles that exist on the

extended runway centerline may make an “early

turn” more desirable than proceeding straight ahead.

In these cases, the published departure instructions

will include the language “turn left(right) as soon as

practicable.” These departures will also include a

ceiling and visibility minimum of at least 300 and 1.

Pilots encountering one of these DPs should preplan

the climb out to gain altitude and begin the turn as

quickly as possible within the bounds of safe

operating practices and operating limitations. This

type of departure procedure is being phased out.


“Practical” or “feasible” may exist in some existing

departure text instead of “practicable.”

2. ODPs, SIDs, and DVAs assume normal

aircraft performance, and that all engines are

operating. Development of contingency procedures,

required to cover the case of an engine failure or other

emergency in flight that may occur after liftoff, is

the responsibility of the operator. (More detailed

information on this subject is available in Advisory

Circular AC 120−91, Airport Obstacle Analysis, and

in the “Departure Procedures” section of chapter 2 in

the Instrument Procedures Handbook,


3. The 40:1 obstacle identification surface

(OIS) begins at the departure end of runway (DER)

and slopes upward at 152 FPNM until reaching the

minimum IFR altitude or entering the en route

structure. This assessment area is limited to 25 NM

from the airport in nonmountainous areas and 46 NM

in designated mountainous areas. Beyond this

distance, the pilot is responsible for obstacle

clearance if not operating on a published route, if

below (having not reached) the MEA or MOCA of a

published route, or an ATC assigned altitude. See

FIG 5−2−1. (Ref 14 CFR 91.177 for further

information on en route altitudes.)


ODPs are normally designed to terminate within these

distance limitations, however, some ODPs will contain

routes that may exceed 25/46 NM; these routes will ensure

obstacle protection until reaching the end of the ODP.

4. Obstacles that are located within 1 NM of the

DER and penetrate the 40:1 OCS are referred to as

“low, close−in obstacles.” The standard required

obstacle clearance (ROC) of 48 feet per NM to clear

these obstacles would require a climb gradient greater

than 200 feet per NM for a very short distance, only

until the aircraft was 200 feet above the DER. To

eliminate publishing an excessive climb gradient, the

obstacle AGL/MSL height and location relative to the

DER is noted in the “Take−off Minimums and

(OBSTACLE) Departure Procedures” section of a

given Terminal Procedures Publication (TPP)


(a) Pilots must refer to the TPP booklet  or the

Graphic ODP for information on these obstacles.

These obstacle notes will no longer be published on

SID. Pilots assigned a SID for departure must refer to

the airport entry in the TPP to obtain information on

these obstacles.

(b) The purpose of noting obstacles in the

“Take−off Minimums and (OBSTACLE) Departure

Procedures” section of the TPP is to identify the

obstacle(s) and alert the pilot to the height and

location of the obstacle(s) so they can be avoided.

This can be accomplished in a variety of ways; for

example, the pilot may be able to see the obstruction

and maneuver around the obstacle(s) if necessary;

early liftoff/climb performance may allow the

aircraft to cross well above the obstacle(s); or if the

obstacle(s) cannot be visually acquired during

departure, preflight planning should take into account

what turns or other maneuver may be necessary

immediately after takeoff to avoid the obstruction(s).