A typical vector to the final approach course and associated  approach clearance is as follows:  “…four miles from LIMAA, turn right heading three four  zero, maintain two thousand until established on the  localizer, cleared ILS runway three six approach.”  Further, controllers must assign headings that  intercept the final approach course no closer than  the following table:  Other clearance formats may be used to fit individual  circumstances, but the controller should always assign an  altitude to maintain until the aircraft is established on a  segment of a published route or IAP. The altitude assigned  must guarantee IFR obstruction clearance from the point at  which the approach clearance is issued until the aircraft is  established on a published route. 14 CFR Part 91, § 91.175  (j) prohibits a pilot from making a procedure turn when vectored to a FAF or course, when conducting a timed approach, or when the procedure specifies “NO PT.” When vectoring aircraft to the final approach course,  controllers are required to ensure the intercept is at least  4-53 parts of the CFRs and notations on instrument approach  charts, which impose on the pilot the responsibility to  comply with or act on an instruction, such as “procedure  not authorized at night.” The name of the approach, as  published, is used to identify the approach. Approach name  items within parentheses are not included in approach  clearance phraseology.  The approach gate is an imaginary point used within ATC  as a basis for vectoring aircraft to the final approach course.  The gate is established along the final approach course one  mile from the FAF on the side away from the airport and is  no closer than 5 NM from the landing threshold. Controllers  are also required to ensure the assigned altitude conforms  to the following:  • For a precision approach, at an altitude not above the glideslope/glidepath or below the minimum glideslope/glidepath intercept altitude specified on the approach procedure chart. • For a non-precision approach, at an altitude that allows descent in accordance with the published procedure. Figure 4-31. DME arc obstruction clearance.  Vectors To Final Approach Course  2  NM  2  NM  4 NM 4 NM  500  feet  500  feet  1,000 feet  Initial segment  Intermediate  segment  500  feet  500  feet  VORTAC  2  NM  2  NM  4 NM  4 NM  Length  The intermediate segment may NOT be less than  5 NM nor more than 15 NM in length, measured  along the arc. The OPTIMUM length is 10 NM.  A distance greater than 10 NM should not be used  unless an operational requirement justifies the  greater distance.  Width  The total width of an arc intermediate segment is 6  NM on each side of the arc. For obstacle clearance  purposes, this width is divided into a primary and a  secondary area. The primary area extends 4 NM  laterally on each side of the arc segment. The  secondary areas extend 2 NM laterally on each side  of the primary area.  Required Obstacle Clearance (ROC)  The ROC is 1,000 feet for the primary initial segment.  The secondary area ROC starts at the primary ROC  surface tapering to zero at the edges of the secondary  area in both initial and intermediate areas. In the  primary area of the intermediate segment, the ROC is  500 feet. 