CHAPTER THREE - FACILITY REQUIREMENTS ANALYSIS

 

 

3.1     GENERAL

 

After the levels of aviation activity have been forecast for the airport, the demand associated with these forecasts must be evaluated relative to the ability of existing facilities to satisfy this demand. Deficiencies highlight facility needs of the airport throughout the planning study. This chapter examines how the 20-year planning horizon for activity translates into the airport's ability to service this traffic and it does so within four distinct elements. They are as follows:

 

·        Airfield Capacity

·        Airfield Development (including critical aircraft determination)

·        Airport Safety and Standards

·        Terminal Area Capacity and Development

·        Land Use Capacity and Development

·        Airspace Capacity and Development

·        Miscellaneous Development

 

Any shortcomings in the ability to serve the forecast demand are highlighted and recommendations are made regarding physical improvements that might be needed.

 

 

 

 

 

3.2     AIRFIELD CAPACITY

 

Weather, runway configuration, aircraft mix, percent touch and go, taxiway exit rating and other similar variables primarily determine airfield capacity. These variables, combined with the percent arrivals and percent of the year certain runway configurations can be used, provide a quantitative breakdown of the airport's annual service volume (ASV). In developing the ASV, we also determine other capacity measures, including VFR hourly capacity. Procedures used in this analysis are consistent with guidelines given in the FAA Advisory Circular 150/5060-5, Airport Capacity and Delay.

 

ASV, as defined by the above-noted circular, is a reasonable estimate of an airport's annual capacity. It accounts for differences in runway use, aircraft mix and weather that would be encountered over the span of a normal year. Using the above-described reference, the annual service volume of the existing airport configuration is 230,000 operations per year. Table 3-1 depicts the ASV relationship to forecast total operations throughout the 20-year term of this airport layout plan update.

 

TABLE 3-1 FORECAST DEMAND VERSUS EXISTING ANNUAL CAPACITY
YEAR	ANNUAL OPERATIONS	PERCENT ANNUAL SERVICE VOLUME1
2000	31,350	13.6%
2005	39,000	16.9%
2010	43,450	18.9%
2020	50,600	22.0%
Note:  (1) Annual Service Volume (ASV):  230,000 operations.

 

 

FAA guidelines suggest that consideration of facility improvements, for increased capacity, be initiated when annual operations reach 60 percent of the ASV. From Table 3-1, we find that there will be no critical stages reached during the study period, relative to the airport's ability to safely accommodate annual traffic activity.

 

 

The peak hour VFR capacity indicates that the maximum number of aircraft operations is 98. Table 3-2 presents the peak hour forecast versus the peak hour capacity.

 

TABLE 3-2 PEAK HOUR FORECAST DEMAND VERSUS HOURLY CAPACITY
YEAR	PEAK HOUR OPERATIONS	PERCENT HOURLY CAPACITY
2000	15	15.3%
2005	18	18.4%
2010	20	20.4%
2020	24	24.5%
Note:  (1) VFR Hourly Capacity:  98 operations.

 

 

From the preceding analysis, we find that there will be no critical stages reached during the study period, relative to the airport's ability to safely accommodate peak-hour aviation activity. The airport capacity appears to be more than adequate to serve throughout the study period.

3.3     AIRFIELD DEVELOPMENT

 

Although airfield capacity relates primarily to the capability of runways and taxiways to handle existing and forecast demand, other runway and taxiway development parameters must also be addressed.

 

First, an analysis of wind data will confirm prevailing wind direction(s) and preferred runway orientations, while wind coverage for existing runways can be computed. Runway length and width geometrics are the next factors typically evaluated. Finally, the taxiway systems at the airport will be discussed.

 

Wind Analysis

The FAA details the objectives of a wind analysis in its Advisory Circular 150/5300-13, Airport Design. It states that the desirable wind coverage for an airport is 95 percent. That is, a runway at a given alignment should have a crosswind component less than a given threshold 95 percent of the time. Typically these are 10.5 knots (12 mph) for small aircraft and 13 knots (15 mph) for large aircraft.

 

Evaluation of wind conditions at the airport was completed with data obtained from the National Climatic Data Center in Asheville, North Carolina. The most current information is based on observations reported from 1997 through 1999. Figure 3.1 illustrates the wind rose for all weather conditions. A summary of the coverages for the all weather wind rose is listed in Table 3-3.

 

TABLE 3-3 ALL WEATHER WIND ROSE ANALYSIS
RUNWAY	WIND SPEED	WIND COVERAGE
15-33	10.5 knots	93.00%
1-19	10.5 knots	90.44%
Combined	10.5 knots	97.18%
15-33	13 knots	96.20%
1-19	13 knots	94.66%
Combined	13 knots	98.75%
15-33	16 knots	98.75%
1-19	16 knots	98.03%
Combined	16 knots	99.56%

 

 

 

Figure 3.2 All Weather Wind Rose

The wind rose information indicates that wind coverage for Runway 15-33 at the 13-knot threshold is 96.20 percent. For 10.5-knot crosswinds on this same runway, the coverage is 93.00 percent. Since 95 percent coverage for the primary runway at the 10.5-knot thresholds is not achieved, it is recommended that the crosswind runway be retained. Combined wind coverage for both Runways 15-33, and 1-19 at the 13-knot crosswind is 98.75 percent, which also meets FAA standards.

 

Runway Analysis

In order to determine runway length, a description of the airport's role and a review of FAA runway length criteria are warranted. To understand the airport's role, an explanation of terminology is necessary.

 

Airport Reference Code

 

The genesis of AC 150/5300-13 has brought about a new airport coding system used to relate airport design criteria to the characteristics of the aircraft anticipated to use the airport. This new coding system is called an airport reference code (ARC). The code has two designators relating to the design aircraft for the airport. The first designator, represented by a letter, is the aircraft approach category and relates to aircraft operational characteristics, namely approach speed. The second designator, represented by a Roman Numeral, is the airplane design group and relates to physical characteristics, namely wingspan.

 

Tables 3-4 and 3-5 present the ARC components for aircraft approach category and airplane design group, respectively.

 

TABLE 3-4 AIRCRAFT APPROACH CATEGORY
CATEGORY	APPROACH SPEED
A	Speed less than 91 knots.
B	Speed 91 knots or more, but less than 121 knots.
C	Speed 121 knots or more, but less than 141 knots.
D	Speed 141 knots or more, but less than 166 knots.
E	Speed 166 knots or more.

 

TABLE 3-5 AIRPLANE DESIGN GROUP
DESIGN GROUP	WINGSPAN
I	Wingspan up to, but not including 49'.
II	Wingspan 49' up to, but not including 79'.
III	Wingspan 79' up to, but not including 118'.
IV	Wingspan 118' up to, but not including 171'.
V	Wingspan 171' up to, but not including 214'.
VI	Wingspan 214' up to, but not including 262'.

 

Some typical aircraft representative of the airport reference codes are:

 

A-I       Single-Engine Aircraft (Cessna 172)

B-II      Multi-Engine Aircraft (Beech King Air)

C-II     General Aviation Aircraft (Grumman G-III)

C-III    Medium-Sized Air Carrier Aircraft (Boeing 737)

D-IV    Larger Air Carrier Aircraft (Lockheed L-1011)

D-V     All Large Air Carrier Aircraft (Boeing 747-200)

 

Critical Aircraft Determination

In airport planning, the Acritical@ aircraft controls one or more design items such as runway length, pavement strength, and separation criteria. The same aircraft is not necessarily critical to all design items. The most demanding aircraft using an airport on a regular basis, defined as an aircraft (or group of aircraft with similar characteristics) conducting at least 500 annual itinerant takeoffs and landings, is called the design aircraft. Toward identifying the design aircraft for Lawrence Municipal Airport, input received from the airport manager, airport users, Kansas Aviation Division, and the FAA was used.

 

Lawrence has in the recent past been classified as an ARC B-II airport. Runway 15-33 is the primary runway and has satisfied the needs of and met the standards for B-II aircraft.  Prior to the new design standards developed in 1989, Runway 15-33 met the standards of a transport class runway. However, the corporate activity has increased over the years to the point that Runway 15-33 has had inadequate length for years.  The first FAA funding request for a longer runway was in the early 1990’s after the last master plan was completed.  This has meant that the corporate aircraft have had to arrive and depart with less than desired fuel and passengers or cargo. Lawrence Runway 1-19, the crosswind runway, serves the needs of B-I aircraft during crosswind conditions.

 

Therefore, to ascertain the current design aircraft for Lawrence, it must be determined which aircraft, or group of aircraft, with the greatest approach speed and/or wingspan, has most recently operated at the airport with over 500 annual itinerant operations.

 

In a survey taken by the FBO, Hetrick Aviation, between 9/17/99 and 4/3/00, a detailed listing of aircraft “N”-numbers was taken along with aircraft type and owners. During the survey, the attempt was to keep track of the larger executive type aircraft. However, there is always subjectivity, therefore some aircraft were not recorded and only the larger aircraft were recorded. The smaller singles and, twins and helicopters were not recorded.  There was more than one operation by many of those aircraft listed.  Many of these aircraft come in very frequently. Appendix C reflects a recordation of the large aircraft and/or jets that operated at the Lawrence Airport in late 1999 and early 2000 by “N” numbers, aircraft make and model and aircraft owner as collected by Hetrick Aircraft, Inc., the airport’s FBO.  There are several items to note:

1.            The recording period was during portions of the winter and spring, which is the slowest time of the year.

2.            Not all aircraft were recorded, as line staff occasionally got busy.

3.            “N” numbers were not in the FAA registry and were not recorded. 

4.            Only twins and larger aircraft over 12, 500 pounds were recorded.

5.            There were fewer special events such as sports games than at other times of the year.

6.            Only one entry was recorded but has been multiplied by two for a landing and a takeoff.  Multiple operations during the occurrence, such as touch-and-go’s, or missed approaches, were not recorded.  Each aircraft was listed just once on the spreadsheet where many of them were in several times.

7.            Local large aircraft operators were not recorded.

8.            The line is manned for 16 hours per day.  Therefore late night drop-offs or pickups were not recorded.

 

Table 3-6 reflects the data:

 

 

 

To correlate this data to a full year, an “annualized factor” or “multiplier factor” was developed from the above factors as follows:

 

Adjustment Factors                                                                                    Multiplier

• Number of days recorded 196 days corrected to 365 days                               1.862
• Slowness of period, add 10 percent                                                                 0.186
• Overlooked count, add 10 percent, add 10 percent                                           0.186
• Aircraft not found in the FAA registry                                                    0.186
• Poor traffic due to weather at the time of special events,

add 5 percent                                                                                                   0.093

• Uncounted Multiple operations (touch and go), add 10 percent              0.186
• After hours drop-offs or pickups, add 5 percent                                                0.093

Resultant Annualized Factor                                                          2.792

 

To this factor, local operations need to be added.  Utilizing the Annualized factor, Table 3-7 reflects the estimated number of operations by aircraft in each category for the year 2000.

 

By adding 100 helicopter operations, the total of 31,350 operations matches the estimated operations as reported by the current FAA’s Master 5010 Form.

 

Therefore, the above includes information about the critical aircraft at the Lawrence Airport.  The critical aircraft is the largest airplane with a composite “family” of aircraft conducting at least 500 annual operations per year at the Lawrence Airport.  Use, aircraft wingspan, and approach speed, determine the critical aircraft.  The existing critical aircraft is in the ARC D-II family of aircraft because 500 operations by D-II aircraft.  Learjet 35A and Gulfstream II, as described in Table 3-8, which is a complete listing of aircraft that operate at Lawrence that are either jet, large airplanes over 12,500 pounds or is a Category C or D aircraft.

Table 3-8 Large non-based Aircraft Operating at Lawrence Airport
Aircraft Type	Aircraft Model	Gross Weight (lbs)	Class
Cessna	Citation 525	10,400	B-II
Cessna	Citation 500	11,850	B-II
Cessna	Citation 501	11,850	B-II
Cessna	Citation I	11,850	B-II
Cheyenne	Republic RC-3	12,135	C-I
King Air	Beech 200	12,500	B-II
Beech	Raytheon 1900D	12,500	B-II
Learjet	Learjet 24	13,000	C-I
Cessna	Citation II	13,300	B-II
Cessna	Citation 550	14,000	B-II
King Air	Beech 300	14,000	C-II
Fairchild	Fairchild SA227-AC	14,500	B-II
Beech	Starship	14,500	D-I
Diamond	Mitsubishi MU-300	14,630	B-II
Learjet	Learjet 25	15,000	C-I
Learjet	Learjet 28	15,000	C-I
Learjet	Learjet 31A	15,500	C-I
Beechjet	Beech 400A	15,780	B-II
Cessna	Citation 560	15,900	B-II
Fairchild	Metroliner	16,500	B-II
Learjet	Learjet 35A	17,000	D-I
Learjet	Learjet 36	18,300	D-I
Dassault