The first and last days of the ARTS data sample were discarded due to the fact that both days did not represent a complete 24-hour day

The 28 remaining days of ARTS data include 11 off-peak days (i.e., weekends, holidays) and are therefore not directly comparable to a complete calendar month

Aircraft not filing a flight plan filed (i.e., those aircraft operating under IFR) are not captured by the ARTS processing software

Flights having low quality signals and/or those containing errant data were discarded from the sample

All aircraft operations included in the ARTS data sample were categorized into the following aircraft categories and subcategories:

Category	Subcategory	Representative aircraft types
Jet-UPS	UPS Heavy Jet (UHJ) UPS Large Jet (ULJ)	B-747, B-767, B-757, DC-8 B-727-100/200
Jet-Other	Other Large Jet (OLJ) Regional Jet (RJ) GA Jet (GJ)	B-737, B-727, DC-9, MD-80, FK100 BAE146, Canadair RJ, EMB-145 Lear 25/35, FA20, G2, WW24
Turboprop	Commuter Turboprop (CT)	BE190, EMB120, SAAB340
	GA Multi Turboprop (GMT)	C402, B190, DHC8
Pistonprop	GA Multi Pistonprop (GMP)	BE58, C414, PA31
	GA Single Pistonprop (GSP)	C172, C208, M20
Military	Military (MIL)	C130

Following the categorization of aircraft, the ARTS data sample was divided into daytime operations (i.e., 7:00 a.m. to 10:00 p.m.) and nighttime operations (i.e., 10:00 p.m. to 7:00 a.m.), because the fleet mix and preferential runway uses at the Airport are different during these periods. Daytime and nighttime operations were then subdivided into the most commonly used runway use configurations.

Based on the Louisville International Airport Informal Runway Use/Noise Abatement Procedures and discussions with FAA airport traffic control tower (ATCT) staff, the following daytime and nighttime runway use configurations (in order of preference) were used in this analysis:

Daytime runway use configurations

Daytime 1 - Land on Runway 17L and depart on Runways 17R and 17L
Daytime 2 - Land and depart on Runways 17R and 17L
Daytime 3 - Land on Runways 35R and 35L, depart on Runway 35R
Daytime 4 - Land and depart on Runways 35R and 35L
Daytime 5 - Land and depart on Runway 29

Nighttime runway use configurations

Nighttime 1 - Land on Runways 35R and 35L; and depart on Runways 17R and 17L (Contraflow)
Nighttime 2 - Land on Runway 17L and depart on Runways 17R and 17L
Nighttime 3 - Land and depart on Runways 17R and 17L
Nighttime 4 - Land on Runways 35R and 35L and depart on Runway 35R
Nighttime 5 - Land and depart on Runways 35R and 35L
Nighttime 6 - Land and depart on Runway 29

The most preferred runway use configurations are Daytime 1 and Nighttime 1, and are used to the maximum extent possible whenever wind, weather, demand, and airfield conditions permit. It should be noted that during Nighttime 1 conditions, some arrivals or departures may occur from/to the north if they are against the general flow of operations. For example, the relatively few departure operations that would be expected during the peak UPS arrival bank will be instructed by the ATCT to depart on either Runway 35R or 35L.

With the exception of Nighttime 6, each identified runway use configuration occurred at least once in the sample of ARTS data. Of the daytime configurations, Daytime 1 occurred most often (55% of total daytime operations), followed by Daytime 3 (18%). Of the nighttime configurations, Nighttime 1 occurred most often (81% of total nighttime operations), followed by Nighttime 2 (6%).

Table A depicts actual runway uses by each aircraft category for the ARTS data sample. As depicted on the table, daytime and nighttime aircraft operations are distinct. During daytime hours, Jet-Other aircraft accounted for 69% of the total daytime operations. Jet-UPS aircraft accounted for approximately 15% of total daytime operations. During nighttime hours, Jet-UPS aircraft accounted for 65% of total nighttime operations. Jet-Other aircraft accounted for 22% of total nighttime operations.

Table A also depicts actual daytime and nighttime arrival and departure runway uses during the sample period. Approximately 75% of all daytime arrivals occurred on Runway 17L and 17R (with 69% on 17L), and approximately 23% of all daytime arrivals occurred on Runways 35R and 35L. For daytime departures, approximately 74% occurred on Runways 17L and 17R, and 25% occurred on Runway 35R and 35L (with 18% on 35R). During nighttime hours, approximately 72% of all arrivals occurred on Runways 35R and 35L, and approximately 85% of all departures occurred on Runways 17R and 17L.

Based on this analysis, the Airport operated in Contraflow (or the Nighttime 1 runway use configuration) approximately 80% of the time during the ARTS sample period. It should be noted that the use of Contraflow observed during this period is consistent with that reported in the RAA’s Contraflow Operations Report. As noted above, some departure or arrivals from/to the north did occur during the Contraflow periods in the four-week ARTS sample.

Methodology
To estimate annual average runway use, ten years of National Oceanic and Atmospheric Administration (NOAA) weather data was processed to estimate annual use of each runway use configurations at the Airport based on specified crosswind and tailwind criteria. Since the Airport has all-weather, independent approach and departure capabilities for each of the primary runway use configurations, wind conditions and demand are the primary factors influencing runway use. The resulting estimates of annual runway use percentages are provided below:

		Day	Night
	North Flow	16.21%	9.25%
	South Flow	83.22	12.47
	Contra Flow	--	78.26
	West Flow	0.57	0.02

The annual percentage of each flow condition is strongly influenced by the allowable cross- and tailwind component. The NOAA data give an hourly average of the wind direction and speed, and as such does not fully portray transient conditions such as wind gusts during the hour, which may be significantly higher than the average. Other conditions which may affect runway use configuration such as the presence of wind shear, wet runways or pilot preference are more difficult to quantify. Therefore, in this analysis the standard tower operation and noise abatement procedures were simplified somewhat and the following cut-off values (as indicated in the table below) where used before shifting to a less desirable configuration. Slightly higher values were assumed for night use, since winds are generally calmer and more stable at night. The assumed "practical" allowable cross and tailwind components are provided below:

		Day	Night
	Tail Wind Component	3 knots	5 knots
	Side Wind Component	15 knots	20 knots

Once the annual use of each configuration was calculated based on the NOAA data, the ARTS sample was normalized based on the estimated annual use of each configuration. In this manner, aircraft operations under each the configuration were appropriately weighted to represent annual average use.

Annual Average Runway Use Assumptions
Table B depicts the existing 1998 and future 2005 annual average runway use assumptions. These assumptions were prepared for daytime and nighttime conditions because the fleet mixes and preferential runway uses at the Airport are different during these periods.

As depicted in Table B, approximately 87% of annual daytime arrivals are assumed to occur Runway 17L and 17R (with 79% on 17L), and approximately 12% of all annual daytime arrivals are assumed to occur on Runways 35R and 35L. For annual daytime departures, approximately 86% are assumed to occur on Runways 17L and 17R, and 14% are assumed to occur on Runway 35R and 35L (with 10% on 35R). During nighttime hours, approximately 71% of all annual arrivals are assumed to occur on Runways 35R and 35L, and approximately 82% of all annual departures are assumed to occur on Runways 17R and 17L. Based on a comparison of data contained in Tables A and B, the assumed annual average runway uses are similar to the actual runway uses determined from the sample of ARTS data.

For this Study, we are assuming that existing and future daytime and nighttime runway use percentages will remain constant since both the daytime and nighttime fleet mixes are projected to remain consistent through 2005. Based on a review of preliminary forecast fleet mix data, the air carrier fleet mix will continue to consist of narrowbody aircraft similar to those included in the Other Large Jet (OLJ) category (e.g., B-737, B-727, DC-9, MD-80, FK100, etc.). The average aircraft seat size is only projected to increase from 119.1 in 1998 to 122.0 in 2005. Based on fleet mix data provided by UPS, the percentage of UPS aircraft requiring the use of Runway 17R-35L is anticipated to remain the same.

EEB/sq
Enclosure
cc: Mr. Robert A. Brown, RAA
Ms. Rande Swann, RAA
Mr. William J. Willkie

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