Standard Instrument Departures (SIDs)—Printed textually and graphically, SIDs are ATC procedures for pilot/controller use to provide obstruction clearance and a transition from the terminal area to the appropriate en route structure. The transition is the last fix on a departure procedure. SIDs are primarily designed for system enhancement and to reduce pilot/controller workload. ATC clearance must be received prior to flying a SID. Pilots are not required to accept a SID if assigned one. Pilots of civil aircraft operating from locations where SIDs are established may expect ATC clearances containing a SID. Use of a SID requires pilot possession of the textual description or graphic depiction of the approved current SID. RNAV SIDs must be retrievable by the procedure name from the aircraft database and conform to charted procedure. ATC must be immediately advised if the pilot does not possess the assigned SID, or the aircraft is not capable of flying the SID. Notification may be accomplished by filing "NO  SID" in the remarks section of the filed flight plan or by the less desirable method of verbally advising ATC. If a SID is part of the clearance, the controller will state the name and number of the SID along with the transition to be flown.