dasc2014 cro at iah airport

ON THE IMPACT OF CONVERGING RUNWAY OPERATIONS AT IAH: RESILIENT OR NOT?

Mr. Wayne Eastus, United Airlines

October 7, 2014

WHAT IS RESILIENCE? � Resilience is:

� “Graceful and expected degradation with planned and achievable recovery such

that no one component drives the “health” of the overall system unless required”

2 ON THE IMPACT OF CONVERGING RUNWAY OPERATIONS AT IAH

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CRO REDUCED RESILIENCE AT IAH AIRPORT

� Results demonstrate that CRO reduces resilience at IAH Airport: � Reduced arrival rate under peak load � Increased taxi-in duration from 26R from ‘before’ to ‘after’ CRO implementation

� Before: land to West, depart from 33s to NW � After: land to West under CRO, depart from 33s to NW

� Adoption of CRO reduced resilience and benefit

ON THE IMPACT OF CONVERGING RUNWAY OPERATIONS AT IAH


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STUDY PURPOSE AND BACKGROUND � Quantify impact of converging runway operations (CRO) at IAH

� Started at IAH on January 15, 2014; � Deployed for use on 26L � FAA waived initial use on 27

� Study examines the before-after impact of CRO at IAH � Impact on use of 26L with CRO is examined with observed data

� CRO is employed at US airports

� BOS, BWI, CLT, DFW, IAD, IAH, JFK, LAS, MEM, MSP, ORD, PHL � FAA monthly report on the impact of CRO � The report measures:

� Average flying time � Average total arrival and departure hourly rates � Average taxi-out duration � Average taxi-in duration

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USE OF CRO AT IAH AIRPORT � Taxi-in duration at peak arrival times � 6.5 minutes during like-configurations (Jan-Jun 2013) � 9.1 minutes when CRO was in use (Jan-Jun 2014) � Max increase of 2.6 minutes � Average increase of 1 minute

� Peak arrival ‘service rate’ drops by 3/hr from pre-CRO to post-CRO � No net loss on daily basis, but… � Transfers delay to enroute phase or departure station

� Demand between pre-CRO to post-CRO differs by 10 ops/day (< 1% difference)

� Performance at IAH will worsen with: � Future demand increase � Use of CRO without modification � Loss of 27 waiver (multiple ADWs)


HOW CRO WORKS

HOW CRO WORKS (HENRY ET AL., 2014 AIAA/ATIO)

� Ensures ‘no-go’ for departure release when arrival is in the ADW ‘box’. � Departure is rolling prior to arrival entering ADW ‘box’

� ADW dimensions ensure 10-9 chance of near mid-air collision between

go-around and departure aircraft

ON THE IMPACT OF CONVERGING RUNWAY OPERATONS AT IAH

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HOW CRO WORKS AT IAH


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27

26L

33R

ADW dimensions Depart 33L and arrive 26L; -0.2 nm to 3.2 Depart 33R and arrive 26L; -0.2 nm to 3.7 nm Depart 33R and arrive 27; -0.8 to 1.0 nm

runway threshold

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STUDY DATA, QUESTIONS, AND METRICS

� Study Data (this is a data-driven analysis) � Pre-CRO time period (no CRO):

� January1, 2013 to July 1, 2013 � Post-CRO time period (CRO used on 26L only):

� January 15, 2014 to June 10, 2014

� <1% ops/day difference between ‘before’ and ‘after’ study periods

� Questions � Has the maximum observed quarter-hour arrival rate changed since CRO started? � Has the average taxi-in duration changed since CRO started, when measured in the

quarter-hour of maximum observed arrival rate?


MAXIMUM QTR-HR ARRIVAL RATE � The bad news: � Average maximum observed qtr-hr arrival rate drops by 3/hr � Departures to IAH suffer APREQ-like delays � Over-subscription by shift from 26R to 26L under CRO mitigated by arrival flow control

� Utilization of runways before and after

� The good news: � More consistent maximum observed qtr-hr arrivals rates under CRO

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arrivals percent departures percent configuration before after configuration before after

26L, 27 54% 2% 33R, 33L 62% 66% 26R, 26L 14% 0%

26R, 27 4% 85% triples 21% 11% triples 5% 8% total 1076 909 total 1076 907


4 6 8 10 12 14 160

0.05

0.1

0.15

0.2

0.25

average taxi-in duration (min) at max qtr-hr arrival rate

freq

uenc

y

at maximum qtr hr arrival

rate = 6.5 (+/- 1.8)

average taxi-in duration (min) at maximum qtr-hr arrival

rate = 9.1 (+/- 1.7)

TAXI-IN DURATION AT MAXIMUM QTR-HR ARRIVAL RATE � Average taxi-in duration increases from 6.5 min to 9.1 min at peak

qtr-hr arrival rate time periods � Caused by arrival shift to 26R and further distance to terminal

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P = 9.1 min

P = 6.5 min


IN SUMMARY

� Recall our definition of resilience… � “Graceful and expected degradation with planned and achievable recovery such

that no one component drives the “health” of the overall system unless required”.

� Operational efficiency outcomes � Increase in taxi-in duration with shift of arrivals from 26L to 26R � Reluctance to push more arrivals reduced the peak arrival rate by 3 per hour � CRO drives operations at the expense of other system components

� Implementation of CRO at IAH should be revisited to: � Reduce taxi-in duration � Recover peak arrival rate capacity � Shift arrivals to 26L with same target level of safety


LOOKING FORWARD � Safety is our number one priority

� CRO should have no negative impact on:

� resilience, efficiency, and capacity

� CRO has validity in risk reduction, but…

� CRO must be adjusted: � to synchronize arrivals to simultaneously-used runways through ADWs � without impact on departures due to ADW asynchronous use

� Synchronizing ADW use could:

� Recover lost arrival and departure capacity during peak periods � Achieve desired target level of safety � Reduce taxi-in duration caused by arrival shift to 26R


WE ARE OPEN TO DISCUSSION

� Looking for a reliable tool to recover lost capacity and maintain safety


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dasc2014 cro at iah airport

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