In addition to heading and altitude assignments, ATC occasionally issues speed adjustments to maintain the required separations. For example: 

“Cessna 30 Alpha, slow to 100 knots.” 

A pilot who receives speed adjustments is expected to maintain that speed plus or minus 10 knots. If for any reason the pilot is not able to accept a speed restriction, the pilot should advise ATC. 

At times, ATC may also employ visual separation techniques to keep aircraft safely separated. A pilot who obtains visual contact with another aircraft may be asked to maintain visual separation or to follow the aircraft. For example: 

“Cessna 30 Alpha, maintain visual separation with that traffic, climb and maintain 7,000.” 

The pilot’s acceptance of instructions to maintain visual separation or to follow another aircraft is an acknowledgment that the aircraft is maneuvered as necessary to maintain safe separation. It is also an acknowledgment that the pilot accepts the responsibility for wake turbulence avoidance. 

In the absence of radar contact, ATC relies on position reports to assist in maintaining proper separation. Using the data transmitted by the pilot, the controller follows the progress of each flight. ATC must correlate the pilots’ reports to provide separation; therefore, the accuracy of each pilot’s report can affect the progress and safety of every other aircraft operating in the area on an IFR flight plan. 

## Departure Procedures (DPs) 

Instrument departure procedures are preplanned IFR procedures that provide obstruction clearance from the terminal area to the appropriate en route structure and provide the pilot with a way to depart the airport and transition to the en route structure safely. Pilots operating under 14 CFR part 91 are strongly encouraged to file and fly a DP when one is available. [Figure 10-2] 

There are two types of DPs: Obstacle Departure Procedures (ODP), printed either textually or graphically, and Standard Instrument Departures (SID), always printed graphically. All DPs, either textual or graphic, may be designed using either conventional or area navigation (RNAV) criteria. RNAV procedures have RNAV printed in the title (e.g., SHEAD TWO DEPARTURE (RNAV)). 

## Obstacle Departure Procedures (ODP) 

ODPs provide obstruction clearance via the least onerous route from the terminal area to the appropriate en route structure. ODPs are recommended for obstruction clearance 

and may be flown without ATC clearance unless an alternate departure procedure (SID or radar vector) has been specifically assigned by ATC. Graphic ODPs have (OBSTACLE) printed in the procedure title (e.g., GEYSR THREE DEPARTURE (OBSTACLE), CROWN ONE DEPARTURE (RNAV)(OBSTACLE)). 

## Standard Instrument Departures 

SIDs are ATC procedures printed for pilot/controller use in graphic form to provide obstruction clearance and a transition from the terminal area to the appropriate en route structure. SIDs are primarily designed for system enhancement and to reduce pilot/controller workload. ATC clearance must be received prior to flying a SID. 

ODPs are found in section C of each booklet published regionally by the AeroNav Products, TPP, along with “IFR Take-off Minimums” while SIDs are collocated with the approach procedures for the applicable airport. Additional information on the development of DPs can be found in paragraph 5-2-7 of the AIM. However, the following points are important to remember. 

1. The pilot of IFR aircraft operating from locations where DP procedures are effective may expect an ATC clearance containing a DP. The use of a DP requires pilot possession of at least the textual description of the approved DP. 

2. If a pilot does not possess a preprinted DP or for any other reason does not wish to use a DP, he or she is expected to advise ATC. Notification may be accomplished by filing “NO DP” in the remarks section of the filed flight plan or by advising ATC. 

3. If a DP is accepted in a clearance, a pilot must comply with it. 

## Radar-Controlled Departures 

On IFR departures from airports in congested areas, a pilot normally receives navigational guidance from departure control by radar vector. When a departure is to be vectored immediately following takeoff, the pilot is advised before takeoff of the initial heading to be flown. This information is vital in the event of a loss of two-way radio communications during departure. 

The radar departure is normally simple. Following takeoff, contact departure control on the assigned frequency when advised to do so by the control tower. At this time, departure control verifies radar contact and gives headings, altitude, and climb instructions to move an aircraft quickly and safely out of the terminal area. A pilot is expected to fly the assigned headings and altitudes until informed by the controller of the aircraft’s position with respect to the route given in 

