4.1 INTRODUCTION The previous chapters have described the existing facilities and provided planning guidelines as well as a forecast of demand for aviation activity at North Perry Airport. The demand/capacity analysis examines the capability of the existing airfield to satisfy the forecasted operational demands of the Airport. This analysis will be expressed in terms of the Airport s annual service volume and hourly capacities. FAA Advisory Circular 150/5060-5, Change 2, Airport Capacity and Delay, provides the methodologies used to conduct airfield analysis, which will establish the existing capacity of the Airport. For this Master Plan Update, airfield capacity will be calculated using two methods, and identified in the terms of: Hourly capacities of the runways defined as the maximum number of aircraft operations (both landings and takeoffs) which can be accommodated on the airport during in an hour. Annual service volume (ASV) of the airfield, which is a reasonable estimate of the capacity of the airport accounting for the overall usage patterns over a year s time. The existing capacity will be then be compared with the demand to determine any airfield deficiencies within the planning period. 4.2 AIRFIELD CHARACTERISTICS According to FAA Advisory Circular 150/5060-5, Airport Capacity and Delay, the elements that affect airfield capacity include: Runway Use Configuration and Instrumentation the alignment of the runways; Taxiway Configuration the location and spacing of the taxiway connectors; Airfield Operational Characteristics, including: Arrival/Departure Balance the percent of arrivals and departures during typical operations; Touch and Go Operations the percent of training operations where aircraft land and immediately takeoff without stopping during typical operations; Aircraft Mix Index the distribution of aircraft fleet by aircraft category that use the airport; and Meteorological Conditions direction, speed, ceiling, and visibility conditions. The analysis of these elements provides the basis for establishing the operational capacity of the airport. 4.2.1 RUNWAY USE CONFIGURATION AND INSTRUMENTATION The airfield configuration for North Perry Airport includes two sets of intersecting parallel runways, two aligned in the north-south direction, and the other two aligned in the east-west direction. Due to the intersecting configuration, only one set of runways can be used at a given time. The distance from centerline to centerline between the north/south runways (Runway 18R-36L and 18L-36R) is 1,450 feet. The distance from centerline to centerline between the east/west runways (Runway 9R-27L and 9L-27R) is 1,466 feet. For each operational configuration, only one runway is used for arriving and/or departing aircraft. Montgomery Consulting Group August 11, 2009 Page 4-1
Runway 9R-27L is the primary runway for the Airport, and Runway 9R is the only non-precision approach for the Airport. The other seven approaches to the Airport are visual. 4.2.2 TAXIWAY CONFIGURATION As detailed in the inventory section, all four runways at North Perry Airport have at least one associated parallel taxiway. Runways 9R-27L, 9L-27R, and 18L-36R have parallel taxiways on both sides of the runway. Based on the FAA criteria contained in FAA Advisory Circular 150/5060-5, Airport Capacity and Delay, the exit factor is maximized when a runway has four exit taxiways within a range determined by the operations using that runway. At North Perry Airport, this range is 2,000 to 4,000 feet from the landing threshold and each exit must be separated by at least 750 feet. Using this criterion, Runways 9R-27L, 9L- 27R, and 18L-36R have at least four exit taxiways in either runway direction that fall within the criteria. Runway 18R-36L has only two exit taxiways in either runway direction that meet the criteria. 4.2.3 AIRFIELD OPERATIONAL CHARACTERISTICS Operational characteristics such as the percentage of aircraft arrivals and departures, and the percentage of touch and go operations can have an affect on the airfield s overall capacity. 4.2.3.1 ARRIVAL/DEPARTURE BALANCE The hourly capacity of the airfield is affected by the number of arrivals versus departures because arrivals require more runway time than a departure. Based on discussions with the airport s tower, arrivals and departures at the Airport are typically balanced (50 percent arrivals, 50 percent departures) during normal operating conditions. These percentages are anticipated to remain consistent throughout the planning period. Pilots currently perform run-ups on the taxiways prior to entering the designated runway. There are not designated run-up areas at or near every end on each runway that would allow an aircraft to by-pass a delayed aircraft. This constraint may impact capacity, but can not be modeled using the FAA s methodology for airfield capacity. To date, the Airport s Air Traffic Control Tower (ATCT) has not identified any constraints due to lack of a separate run-up area. 4.2.3.2 TOUCH AND GO OPERATIONS A touch and go is a practice maneuver where a pilot touches down, slows to an exit speed, and then accelerates for take-off without exiting the runway. Two operations are counted for each touch and go; one operation for landing, and one operation for the takeoff. Airfield capacity is greater if touch and go activity occurs since it takes less time for the same aircraft to land and depart than it does for one aircraft to land and another to depart. Touch and go operations are normally associated with flight training. Based on discussions with the Airport s ATCT, approximately 50 percent of operations at North Perry Airport are touch and go operations, indicating a high percentage of training operations occurring at the Airport. Touch and go operations are anticipated to remain between 40 to 50 percent during the planning period. Montgomery Consulting Group August 11, 2009 Page 4-2
4.2.4 AIRCRAFT MIX INDEX The fleet mix of the different aircraft types that use the Airport affects the overall capacity of the airport. The approach speed and weight of an aircraft impact the length of time the aircraft will occupy the runway. The FAA has established a classification system for the various sizes, weights, and performance of aircraft as shown in Table 4.1. TABLE 4.1 AIRCRAFT CLASSIFICATION SYSTEM FOR AIRFIELD CAPACITY ANALYSIS Classification Maximum Certified Takeoff Weight (lbs.) Number of Engines Wake Turbulence Classification Class A 12,500 or less Single Small Class B 12,500 or less Multi Small Class C 12,500 to 300,000 Multi Large Class D over 300,000 Multi Heavy Source: FAA AC 150/5060-5, Change 2, Airport Capacity and Delay Broward County s current ordinance restricts operations at North Perry Airport to aircraft weighing 12,500 pounds or less. This weight restriction provides that only Class A and Class B aircraft may use the Airport. Illustrations of the types of aircraft by class that operate at the North Perry Airport are shown in Figure 4.1. The forecasted activity indicates the Airport will continue to serve Class A and Class B aircraft operations. No Class C or Class D aircraft operations are forecasted at North Perry Airport. Using the FAA formula for aircraft mix, the existing and future mix index for North Perry Airport is zero (the FAA formula does not count Class A or Class B aircraft in determining aircraft mix). Montgomery Consulting Group August 11, 2009 Page 4-3
FIGURE 4.1 ILLUSTRATION OF AIRCRAFT TYPES BY CLASS AT NORTH PERRY AIRPORT Source: Aircraft manufacturer records 4.2.5 METEOROLOGICAL CONDITIONS FAA recognizes three measures of cloud ceiling and visibility in calculating the capacity of an airport, including: Visual Flight Rules (VFR) conditions - occur whenever the cloud ceiling is at least 1,000 feet above ground level (AGL) and visibility is at least three statute miles. Instrument Flight Rules (IFR) conditions - occur when the cloud ceiling is at least 500 feet AGL and less than 1,000 feet AGL and visibility is between one and three statue miles. Poor Visibility and Ceiling (PVC) occur when the cloud ceiling is less than 500 feet AGL or visibility is less than one statue mile. IFR or PVC conditions reduce airfield capacity because IFR conditions require a greater separation distance during operations. Based on information provided by the Airport s tower, it is estimated that North Perry Airport experiences VFR conditions 95 percent of the time, IFR conditions exist 4.5 percent of the time, and PVC conditions exist 0.5 percent of the time. These conditions are expected to remain consistent throughout the planning window. Montgomery Consulting Group August 11, 2009 Page 4-4
4.3 AIRFIELD CAPACITY ANALYSIS The characteristics of the airfield were used in conjunction with the methodologies contained in FAA Advisory Circular 150/5060, Airport Capacity and Delay, to generate values for airfield capacity for this Master Plan Update. These values include the hourly capacity of the runways and the annual service volume. 4.3.1 HOURLY CAPACITY OF THE RUNWAYS Hourly capacity of the runways are determined by analyzing the appropriate VFR and IFR figures for the airport s runway configuration contained in FAA Advisory Circular 150/5060, Airport Capacity and Delay. From these figures, the aircraft mix index and percentage of aircraft arrivals are used to determine the base hourly capacity. A touch and go factor is determined based on the percentage of touch and go operations combined with the aircraft mix index. The FAA figures also consider the taxiway exit factor, which is determined by the aircraft mix index, percent of aircraft arrivals, and the number of exit taxiways that are within the specified exit range. The hourly capacity for runways is determined by the following equation: Where: Hourly capacity = C* x T x E C* is equal to the hourly capacity base; T is equal to the touch and go factor; and E is equal to the exit factor. The aircraft mix can change the value of the hourly capacity. However, since all planning years are assumed to have a mix index of zero (only Class A and Class B aircraft), there is no anticipated changes in the hourly capacities of the Airport over the planning horizon. A weighted hourly capacity is calculated by taking the VFR and IFR calculations and applying them to the percentage these conditions occur at the airport. The following hourly capacity values were calculated for North Perry Airport: VFR Conditions = 195 Operations/Hour IFR Conditions = 24 Operations/Hour Weighted Hourly Capacity = 186 Operations/Hour 4.3.2 ANNUAL SERVICE VOLUME The annual service volume (ASV) represents the approximate number of total operations that the airport can support in one year. The ASV is the theoretical capacity or limit of operations that the airport can safely accommodate. Using the methodology contained in FAA Advisory Circular 150/5060, Airport Capacity and Delay, the annual service volume equation is as follows: Where: Cw D H Annual Service Volume = Cw x D x H is equal to the weighted hourly capacity; is equal to the ratio of annual demand to average daily demand during the peak month; and is equal to the ratio of daily demand to average peak hour demand during the peak month. Montgomery Consulting Group August 11, 2009 Page 4-5
The ASV takes into account differences in forecasted activity levels, runway use, aircraft mix, weather conditions, and other factors that may vary within a single year. For North Perry Airport, these factors will remain relatively the same. Additionally, the other factors (ratios D and H) are very similar since the same methodology for calculating the percent of average day peak month and peak hour operations was used for each year in the forecast chapter. The ASV of North Perry Airport was based on the most conservative calculations contained in FAA Advisory Circular 150/5060, Airport Capacity and Delay. The ASV for the Airport was estimated to be 440,000 operations. 4.4 COMPARISON OF AIRFIELD CAPACITY VS. DEMAND The airfield capacity analysis for North Perry Airport was compared to the projected demand for aviation operations to identify any present or potential deficiencies in the airfield system. Table 4.2 lists the demand versus airfield capacity for the peak hour and annual service volume (ASV) for the study period. According to FAA Order 5090.3B, Field Formulation of the National Plan of Integrated Airport Systems (NPIAS), eligibility for federal funding to address capacity limitations is available once the airfield has reached 60 percent of its current capacity. Starting planning at this level should allow for improvements to be made prior to demand levels exceeding capacity of facility. A demand that exceeds the annual service volume is likely to result in significant delays on the airfield. Table 4.2 also illustrates the future capacity levels for the airport based on the forecasted annual operations and the ASV for the airport. TABLE 4.2 DEMAND VS. AIRFIELD CAPACITY CHART ANNUAL SERVICE VOLUME (ASV) NORTH PERRY AIRPORT Forecast Year Forecast Demand Existing Capacity Operational Deficiency Capacity Level 2006 146,544 440,000 No 33.3% 2011 159,089 440,000 No 36.1% 2016 171,548 440,000 No 40.0% 2026 192,881 440,000 No 43.8% Source: Montgomery Consulting Group, Inc. Figure 4.2 graphically illustrates the ASV versus the forecasted total operations. This figure shows a theoretical timeline when the planning and construction thresholds may be crossed; however, it is important to understand that the actual demand for the facilities will be the driver of the development rather than the year itself. This concept will enable the Broward County Aviation Department to accelerate, maintain, or decelerate facility improvements as the airport continues to operate. Montgomery Consulting Group August 11, 2009 Page 4-6
4.5 SUMMARY OF Figure 4.2 illustrates that even if no improvements are made to the airfield, North Perry Airport should not experience any capacity related problems during the planning period. Overall, the current airfield capacity is considered to be sufficient to accommodate the forecast airport operations. However, as conditions change in the future, the capacity of the airfield may decrease enough to reach the 60 percent planning threshold. If and when this milestone is reached, capacity improvement projects will need to be evaluated to enhance the overall capacity of the airport. The hourly capacity of IFR operations without an instrument landing system or precision approach is substantially reduced from a runway with a precision instrument landing system. Although, IFR operations have generally accounted for a small percentage (less than 2 percent) of the overall operations, adding instrument approach capabilities would increase the hourly capacity under IFR conditions, and slightly increase the annual service volume. The alternatives analysis section of the plan will explore options to add precision instrument capabilities to the airport. FIGURE 4.2 FORECAST DEMAND VERSUS EXISTING ASV CAPACITY GRAPH NORTH PERRY AIRPORT Sources: Forecast Demand Terminal Area Forecast, March 2006 ASV estimate Montgomery Consulting Group, Inc. based on FAA Advisory Circular 150/5060, Airport Capacity and Delay Montgomery Consulting Group August 11, 2009 Page 4-7