[Code of Federal Regulations]
[Title 14, Volume 2]
[Revised as of January 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 14CFR121.171]

[Page 744-745]
 
                     TITLE 14--AERONAUTICS AND SPACE
 
CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION 
                               (CONTINUED)
 
PART 121_OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL 
OPERATIONS--Table of Contents
 
          Subpart I_Airplane Performance Operating Limitations
 
Sec.  121.171  Applicability.

    Source: Docket No. 6258, 29 FR 19198, Dec. 31, 1964; 30 FR 130, Jan. 
7, 1965, unless otherwise noted.

    Editorial Note: Nomenclature changes to subpart I appear at 60 FR 
65928, Dec. 20, 1995.


    (a) This subpart prescribes airplane performance operating 
limitations for all certificate holders.
    (b) For purposes of this part, effective length of the runway for 
landing means the distance from the point at which the obstruction 
clearance plane associated with the approach end of the runway 
intersects the centerline of the runway to the far end thereof.
    (c) For the purposes of this subpart, obstruction clearance plane 
means a plane sloping upward from the runway at a slope of 1:20 to the 
horizontal, and tangent to or clearing all obstructions within a 
specified area surrounding the runway as shown in a profile view of that 
area. In the plan view, the centerline of the specified area coincides 
with the centerline of the runway, beginning at the point where the 
obstruction clearance plane intersects the centerline of the runway and 
proceeding to a point at least 1,500 feet from the beginning point. 
Thereafter the centerline coincides with the takeoff path over the 
ground for the runway (in the case of takeoffs) or with the instrument 
approach counterpart (for landings), or, where the applicable one of 
these paths has not been established, it proceeds consistent with turns 
of at least 4,000 foot radius until a point is reached beyond which the 
obstruction clearance plane clears all obstructions. This area extends 
laterally 200 feet on each side

[[Page 745]]

of the centerline at the point where the obstruction clearance plane 
intersects the runway and continues at this width to the end of the 
runway; then it increases uniformly to 500 feet on each side of the 
centerline at a point 1,500 feet from the intersection of the 
obstruction clearance plane with the runway; thereafter it extends 
laterally 500 feet on each side of the centerline.

[Doc. No. 6258, 29 FR 19198, Dec. 31, 1964, as amended by Amdt. 121-132, 
41 FR 55475, Dec. 20, 1976]