Estimated Fuel Burn Performance for MDW Arrivals

Abstract

The results of the analysis indicate that, during Instrument Meteorological Conditions (IMC), the RNP approach to 13C uses an average of 14% less fuel than the ILS approach on to 13C. For narrow body aircrafts, this is equivalent to on an average a savings of $47 per flight per approach (at $3 a gallon). During Visual Meteorological Conditions (VMC) the least average fuel burn arrival flow for VFR approach procedures is to runways 4R or 31C (174.9 kg) followed by 13C (+11%), and 22L (+19%). During Instrument Meteorological Conditions (IMC) the least average fuel burn arrival flow for ILS approach procedures is to runway 31C (207.06 kg) followed by, 4R (+6.5%) and 13C (+33%). To ensure equity in fuel burn between flights arriving from the east and the west during VMC, 13C is the most equitable runway with the 14% difference in fuel burn between east and west flows, followed by 4R (18% difference), 22L (96% difference) and 31C (148% difference). During IMC, 13C (56%) is the most equitable runway followed by 4R (72%) and 31C (211%).For narrow body aircrafts at MDW, the fuel burn rate in level flight (35 kg/min) is 108% greater than the fuel burn for near-idle descent segments (15 kg/min) and 25% greater than fuel burn on the final approach segment (25 kg/min). These results quantify the benefits of the RNP approach onto 13C and identify an opportunity for a decision-support tool to select runway configuration based on wind magnitude/direction, as well as fuel burn.

Benefits analysis of RNP approach procedure to runway 13C at Midway airport

“…The benefits of RNP approach are limited to IMC days as fuel burn performance of visual approaches is better than RNP approach [5], therefore airlines would prefer visual approach over RNP in VMC. At MDW the potential benefits of RNP approach to 13C is limited to on average 1.6% (IMC when runway 13C is used) of the time per year.…”

“…The summary of the benefits of RNP approach over ILS approach to runway 13C at MDW for B73's aircraft as estimated by previous work ( [4], [5]) are shown in Table 1 and Table 2.…”

“…c. Compute the cumulative turn angle for each filtered sub-track in the rectangular boundary. d. Determine the holding tracks by filtering out sub-tracks with cumulative turn angle greater than 360 degrees e. Compute average fuel burn per holding patterns using the fuel burn model described in [5]. At MDW not all holding patterns for arrivals to runway 13C during IMC are due to flow conflict with ORD operations.…”

“…These weights are used to allocate the total arrival at the airport to flows (at MDW flows are from the east or the west). These ( ) is the average fuel-burn per aircraft for TRACON flow from direction (east or west in case of MDW) obtained from the TRACON flow analysis [4], [5] described in the previous section .…”

“…This was further extended to estimate the fuel burn performance of these flows using actual trajectory of the aircraft, while taking into consideration the energy state (kinetic -true air speed and potential -altitude) of the aircraft at discrete intervals along the flight trajectory [5]. The analysis showed that the RNP approach to 13C at MDW is more efficient (i.e., ILS approach is longer by 9% in terms of track time 1 ) than the corresponding ILS approach and less efficient (i.e., the visual approach is shorter by 16% on average in terms of track time) than the corresponding visual approach [4].…”