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3/21/80 5050.4 result in cumulative noise levels not exceeding 60 Day/Night Level (Ldn) more than 5,500 feet from start of takeoff roll or 65 Ldn on the runway itself. ,.... Adjusted jet operations of 700 or less do not produce a 60 Ldn contour using this method. Note that the Crcana cirA inn 500a the Gates Learjet 35A, and any other jet aircraft producing equivalent or less levels of noise are quieter. than many propeller aircraft under 12,500_pougds,and. therefore may be counted., as propeller aircraft rather than jet aircraft,..; r_ (b) A noise analysis is needed for proposals which individually or cumulatively involve airport location, runway location, major runway extension, or runway strengthening at any airport which is either: 1 Larger than basic transport, 2 Utility or basic transport at which forecast operations exceed those defined in (a) above, 3 Highly controversial because of noise impacts (reference paragraph 24b), or 4 Anticipated frequent usage by special aircraft such as helicopters in proximity to noise sensitive areas. (c) When required by (b), an initial noise analysis may be accomplished by using Report No. FAA-AS-75-1 to develop contours of equal noise exposure using the Ldn cumulative noise methodology or by making a single point analysis using Report No. EPA 550/9-77-450, Calculation of Day/Night Levels (Ldn) Resulting from Civil Aircraft Operations. Such analy- ses shall be sufficient to identify whether any existing or planned noise sensitive areas outside airport boundaries would be exposed to noise levels exceeding 65 Ldn for present conditions and forecast conditions with and without the preferred alternative. Single point analysis where the flight paths cross airport boundaries may be sufficient for making this determination. The analysis shall consider the effects of other related actions, including installation of navigational aids and air traffic control procedures, reflect ing as applicable the results of coordination with affected FAA operating services. (d) If the initial noise analysis indicates that there are no existing or planned noise sensitive areas (as described in paragraph 85b) within the current or projected 65 Ldn 0R that the cumulative increase in noise levels in such areas within 65 Ldn does not exceed 3 Ldn over that created without the project, no further analysis is necessary and it may be assumed that there would be no significant noise impact. To determine the amount of increase, it is necessary to consider the cumulative effects of related_actions as more particularly described in paragraph 26 as well as effects of any noise abatement procedures which exist. If these thresholds are exceeded, additional noise analysis is needed, as described in para- graph 85a. Chap 5 Par 47 Page 29,