INSTRUMENT DEPARTURE PROCEDURES

Instrument Departure Procedures Lesson by wifiCFI


Departure Procedures

What is an Instrument Departure Procedure?

An Instrument Departure Procedure is a way for pilots to transition from the Departure Airport (after takeoff) to the En-Route flight structure. 

Pilot’s must have, at a minimum, a textual description of the Departure Procedure in order to execute it.

A pictorial description of the Departure is often helpful but not mandatory.

The 2 Types of Departures:

ODP (Obstacle Departure Procedure)

Essentially climbs the pilot up to a safe altitude within the near vicinity of the airport.

After reaching a safe altitude the pilot will join an En-Route structure.

SID (Standard Instrument Departure)

Climbs the pilot on a course (N, E, S, W) to join the En-Route structure and continue the flight in the specific direction.

Note:

If a pilot does not wish to fly a SID he/she must annotate “NO SID” on the Filed Instrument Flight Plan.

Departure Brief

Let’s take a look at the information that is pertinent to a pre-departure brief.

First, we will note the communication and navigation frequencies associated with the departure.

Next, we will note and brief the obstacles associated with our expected departure runway.

For our example, let’s assume a Runway 21 Departure.

“DER” stands for “Distance from End of Runway”

Next, we will note and brief the Runway 21 Takeoff Minimums.

We see that the procedure notes “Standard” Takeoff Minimums for Runway 21.

For FAR Part 91 Operations there are no minimum visibility requirements. (FAR 91.175(f))

This means you could legally depart with a zero visibility value.

The Standard Climb Gradient is 200FPNM. (AIM 5-2-8)

Standard Departure Minimums Part 91 Operations

Visibility: None

Climb Gradient: 200FPNM

For understanding purposes, let’s discuss the Takeoff Minimums for Runway 17.

A takeoff from Runway 17 is “Not Applicable” due to obstacles.

In other words, we would need to select a different runway to depart from.

For understanding purposes, let’s discuss the Takeoff Minimums for Runway 3.

The first part of the Runway 3 Takeoff Minimums states “Standard.”

This Standard is referring to visibility requirements that do not apply to Part 91 Operations.

The second part of the Runway 3 Takeoff Minimums explains the non-standard minimum climb gradient.

It states, that a takeoff from Runway 3 requires a climb gradient of 356FPNM (instead of the 200FPNM standard) to be maintained to 6,100’ MSL.

Converting FPNM (Feet Per Nautical Mile) to FPM (Feet Per Minute)

The Formula: (Groundspeed X FPNM)/60 = FPM

Example

How may FPM will we need to climb for a Departure from Runway 3 if GS = 120 Knots?

120GS X 356FPNM = 42,720

42,720/60 = 712FPM

We would need to maintain a minimum climb of 712FPM until reaching 6,100’ MSL.

For understanding purposes, let’s discuss the Takeoff Minimums for Runway 3.

The third part of the Runway 3 Takeoff Minimums states the “Climb In Visual Conditions Requirements.”

Example

Let’s assume our airplane will be unable to climb 712FPM to 6,100’ MSL as we figured on the previous slide.

In this situation, we could still depart runway 3 and climb in visual conditions if…

The ceilings at the airport are at least 4,200’ AGL 

And the visibility is at least 3SM.

The “3” also means we must remain within 3 miles of the airport while performing the climb in visual conditions.

Note:

A “Climb in Visual Conditions” is only required when…

The minimum FPM Climb Gradient cannot be met.

Flying the Departure

Let’s now examine how we would fly the EMONT2 Departure Procedure with a takeoff from Runway 21.

We would first look at the Textual Route Description.

Then compare that information with the Pictorial Route Description.

This same process would be followed regardless of Departure Runway Assignment.

SID (Standard Instrument Departure)

As can be seen from the EMONT2 Departure from KOGD, Obstacle Departure Procedures (ODP’s) climb the pilot up to a safe altitude within the airport vicinity.

After reaching a safe altitude, the pilot can depart on the assigned route of flight for the “En-Route” portion.

Standard Instrument Departures (SID’s) on the other hand, climb the pilot to the “En-Route” portion of a flight in a specific direction (N, E, S, W), not just in the airport vicinity.

FAA Sources Used for This Lesson

Federal Aviation Regulations Part 91

Instrument Flying Handbook


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