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Capacity of a Single Runway. Kimberly Afcha and Danielle Hettmann . Maximum Throughput Capacity (MCT). Measure of capacity of the runway Based on the following assumptions: Continuous supply of arrivals and/or departures Air Traffic Control rule – no simultaneous Runway Occupancy (SRO)
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Capacity of a Single Runway Kimberly Afcha and Danielle Hettmann
Maximum Throughput Capacity (MCT) • Measure of capacity of the runway • Based on the following assumptions: • Continuous supply of arrivals and/or departures • Air Traffic Control rule – no simultaneous Runway Occupancy (SRO) • Air Traffic Control rule – safe Wake Vortex Separation Distances between two flights • Static fleet mix • Approach procedure does not change
MCT of a Runway Five considerations: • 1. ATC Safety Rule: no Simultaneous Runway Occupancy (SRO) • 2. ATC Safety Rule: Maintain Wake Vortex Separation Distance between lead and follow aircraft • 3. ATC Controller/Pilot Separation Control Accuracy: ATC/Pilots insert a buffer distance to avoid violating separation rules • 4. Fleet Mix: determines the type of aircraft in the lead-follow pairs. The type of aircraft determines the separation distance used. Small aircraft following large aircraft require longer distances than large aircraft following large aircraft. • 5. Final Approach Path Distance: the length of time lead-follow aircraft fly the approach in pairs and separation
MCT for Homogeneous Fleet Mix • Simultaneous Runway Occupancy (SRO): • MCT = 3600 seconds/ROT • Wake Vortex Separation Distance • Determined by separation distance • Wake vortices generated off wing-tips of aircraft • Strength of the vortex is governed by the weight, speed, and shape of the wing of the generating aircraft
Minimum Separation Distance • MCT = 3600 / (s/v) where t = s/v • t = inter-arrival time • s = distance between aircraft at runway threshold • v = groundspeed of aircraft • Example: Heavy following Heavy, t=96 seconds • MCT = 36000 / 96 = 37.5 flights/hour
ATC/Controller Separation Buffer • Separation distance is determined through coordination of ATC and pilot • Separation Buffer: • MCT = 3600 / ((s/v)+b) • t = inter-arrival time • s = distance between aircraft at runway threshold • v = groundspeed of aircraft • b = buffer • Example: Heavy following Heavy, t=96 seconds • MCT = 36000 / (96 + 10)= 34 flights/hour
MCT for a Homogeneous Fleet Mix • MCT = Min(MCTSRO, MCTWVSD, MCTWVSDB) • SRO = Single Runway Occupancy • WVSD = Wake Vortex Separation Distance • WVSDB = Wake Vortex Separation Distance and Buffer (ATC/Controller Buffer) • Simplified to: • MCT = Min(MCTSRO, MCTWVSDB)
MTC-Non Homogenous Fleet Mix MTC = Min ( MTCSRO, MTCWVSDB)
MTC- Simultaneous Runway Occupancy Rule • Runway Occupancy Time (ROT) • Probability of lead-follow
Computing E[ROT] E[ROT] = Σi(pi * ROTi) E[ROT] = (.3*80) + (.2*65) + (.25*50) + (.25* 45) = 60.75
MTC-Simultaneous Runway Occupancy Rule MTCSRO= 3600/ E[ROT] MTCSRO= 3600/60.75 = 59.26
MTC-Wake Vortex Separation Rule • The separation distance between the lead and the follow (sij) • The groundspeed of the aircraft (vj) • The probability of a lead-follow pair (pij)
MTC-Wake Vortex Separation Rule • Inter-arrival time (tij) • Inter-arrvial time matrix T E[Tij] = ΣiΣj (pij *( Tij))
MTC-Wake Vortex Separation Rule Tij = sij/vj for compression case Tij = ((r + sij)/vj ) – (r/ vi ) for separation case
Compression Case • Lead slower than Follow • Compression distance- additional distance used by Follow as it catches up to Lead • Compression Time = r/(Vj – Vi) • Cases: H-H, H-L, H-M, H-S, L-L, L-M, L-S, M-M, M-S, S-S
Separation Case • Lead faster than Follow • Separation Distance- additional distance at the runway threshold caused by Lead faster than Follow • Separation Time= ((r + sij)/vj ) – (r/ vi ) • Cases: S-M, S-L, SH, M-L, M-H, H-L.
MTC-Wake Vortex Separation Rule MTC = 3600 seconds/E[tij] E[tij]= (.09*120)+(.06*188)+…+(.06*120) =141.9 MCT = 3600 seconds/141.9 = 25.368
MTC-Wake Vortex Separation Rule with Buffer Distance MTC = 3600/E[tij] Where tij = Tij + b E[tij]= 146.9 seconds MTC= 3600/ 146.9 = 24.505 arrivals per hour
MTC-Non Homogenous Fleet Mix Recall MTC = Min ( MTCSRO, MTCWVSDB) MTC = Min (59.26, 24.505) = 24.505 arrivals per hour