Presented at AGIFORS Annual Symposium. This presentation analyzes airport gate usage and delays across U.S. carriers during the summer 2012 season. Using the masFlight data warehouse, I demonstrate differences in gate utilization strategies, scheduled and actual aircraft turn times, and how those strategies impact operational robustness and delays. I show how individual gate assignments can make significant differences in on-time performance, opening opportunities for granular block time planning and airport-level coordination.

1. Unlocking the Power of Aviation Operations Data
Assessing airport gate usage
Utilization, turn times and delays
AGIFORS Symposium
October 12, 2012
Joshua Marks
Chief Executive Officer
josh@masflight.com
Mobile. +1 703-994-0000
4833 Rugby Avenue, Suite 301
Bethesda, Maryland 20814 USA
www.masflight.com

2. OVERVIEW
Study of gate scheduling, usage and delays
Scope and Methodology
This study reviews how U.S. carriers
schedule gate operations and execute
Airlines studied: turns, and how those factors impact
American, Alaska, JetBlue, Delta,
AirTran, Spirit, United, US Airways, departure and taxi delays by airport
Virgin America and Southwest
Time period analyzed: • Large-scale analysis covering 3 months
June 1, 2012 through August 31, 2012
Stations in data set: • Multi-airline, with both hub-and-spoke and
U.S. and Puerto Rico airports point-to-point carriers on domestic and
international routes from the U.S.
Flights included:
All domestic and international flights
including those by regional affiliates • Gate turns based on airline-reported data
(published via FIDS or flight status systems)
Records in data set:
1.6 million flights with gate & turn data
at 3,900 discrete airline gates • Aligns with schedule information to match
gates to airline terminals and operators
Data source:
masFlight
(includes data from FlightStats, OAG, DOT)
• Incorporates weather and delay causes
in order to discern patterns in gate congestion
SOURCE: masFlight (masflight.com)

3. DEFINITIONS
Definitions
Scheduled Turn Time Actual Turn Time Gate Utilization
The scheduled time The actual time Number of flights
planned at the gate gate in to gate out, that depart daily from
between inbound and for a single aircraft a given gate, including
outbound flights at a given station RONs and gate-tows
Gate Buffer Time Hold-Outs Delay Generation
The time between Flights that land to an Departure delay of the
gate operations, from occupied gate or a outbound flight minus
each gate departure to blocked ramp area, the arrival delay of the
the next arrival requiring taxi-in hold preceding inbound
SOURCE: masFlight (masflight.com)

4. D ATA S E T U S E D
Completeness of Data Set
We compiled a sufficiently broad data set to conduct this analysis
Data Set Coverage Our data set included all flights where
Airline
as % of Flights we could identify a clean gate turn
American* 98% and distinct departure gates
Alaska 80%
• For turn times we eliminated RONs,
JetBlue 85% gate tows, and concurrent departures from
Delta* 98% the same gate. We included actual turns
between 20 and 240 minutes.
Frontier 98%
Spirit 98% • Where possible matched tail numbers as
well as aircraft gate data to determine
United* 89%
aircraft turn time and gate utilization
US Airways* 98%
• When gate data unavailable (Puerto Rico
Virgin America 91%
and Alaska) we had comparably lower
Southwest 100% coverage – Alaska Airlines and JetBlue
* Coverage excludes certain small and non-US stations
SOURCE: masFlight (masflight.com)

5. A N A LY Z I N G S C H E D U L E D T U R N S
Scheduled Turns: Major Hub Carriers
American – Scheduled Turns American – Delays
0 20,000 40,000 60,000
by Scheduled Turn We looked at how legacy
31.6
31.5
0-29 min
hub carriers scheduled
turns across their networks
26
30-44 min
Minutes of Delay
45-59 min
• Domestic mainline turns
60-74 min
10.3
10.1
9.7
9.7
9.2
9.1
8.3
8.2
• Most between 45 and 60 minutes
7.8
6.5
75-89 min
90-119…
• Large aircraft require longer turns
120+ min
30 35 40 45 50 55 60 65 70 75 80 85 90
Scheduled Turn Time
• 30-min turns due to aircraft
(5 minute increments) swaps and non-routines
United – Scheduled Turns United – Delays • Delay minutes significantly
by Scheduled Turn higher for <45 minute turns
0 10,000 20,000 30,000 40,000 50,000
40.9
37.6
0-29 min
• American shows stability in
30-44 min delay minutes across turn times
Minutes of Delay
22.4
45-59 min
21.3
21.1
20.9
• United has expected pattern:
17.7
17.5
17.4
15.2
60-74 min
14.6
13.9 as scheduled turn times
15
75-89 min
increase, the delay minutes
90-119 min incurred decrease
120+ min
30 35 40 45 50 55 60 65 70 75 80 85 90
Scheduled Turn Time
(5 minute increments)
SOURCE: masFlight (masflight.com)

6. A N A LY Z I N G S C H E D U L E D T U R N S
Scheduled Turns: Hub Carriers w/Smaller Aircraft
JetBlue – Scheduled Turns JetBlue – Delays
by Scheduled Turn Time JetBlue, Delta, US Airways &
37.2
0 5,000 10,000 15,000 20,000
Spirit had a mix of turn times
0-29 min
with more 30-44 minute turns
30-44 min
Minutes of Delay
than United or American
45-59 min
14.9
14.9
14.1
13.9
13.8
13.7
13.4
13.3
60-74 min • Domestic mainline turns
10.6
10.5
10.4
12
75-89 min
• Quicker turns at outstations
90-119 min
and away from key hubs
120+ min
30 35 40 45 50 55 60 65 70 75 80 85 90
Scheduled Turn Time (5 minute • Consistent distribution of turn
increments)
times across this airline set
Delta – Scheduled Turns Delta – Delays
by Scheduled Turn Time
• Mainline smaller jets (EMB-
0 20,000 40,000 60,000 190, DC-9 series)
21.7
0-29 min drives faster pace as well
Minutes of Delay
30-44 min
14.5
• Delta has similar pattern as
45-59 min
United – as turn time increase,
9.2
60-74 min delays decrease
7.1
6.2
6.1
5.8
7
5.5
4.9
4.7
4.5
75-89 min
5
• Demonstrates importance of
90-119 min
aircraft mix and how turn time
120+ min 30 35 40 45 50 55 60 65 70 75 80 85 90 insulates inbound delays
Scheduled Turn Time (5 minute
increments)
SOURCE: masFlight (masflight.com)

7. A N A LY Z I N G S C H E D U L E D T U R N S
Scheduled Turns: LCCs with utilization priority
Southwest – Scheduled Turns Southwest – Delays
by Scheduled Turn
0 100,000 200,000 For quick turn airlines, several
16.3
0-29 min new factors to consider
15.1
15.1
16
14.8
14.5
13.8
13.5
13.4
Minutes of Delay
12.4
30-44 min
12.2
11.1
• Southwest and AirTran have
11
45-59 min
similarities in gate turn planning
60-74 min
75-89 min
• Material differences in aircraft size
90-119 min (717 vs. 73G/H), product
120+ min and carry-on bags!
30 35 40 45 50 55 60 65 70 75 80 85 90
Scheduled Turn Time
(5 minute increments) • Short turns for Southwest are
routine; 30-minute scheduled
AirTran – Scheduled Turns AirTran – Delays
by Scheduled Turn turns for AirTran reflect swaps
0 10,000 20,000 30,000
24.8
0-29 min • Southwest schedules longer turns
30-44 min at congested stations that are
Minutes of Delay
45-59 min associated with longer delays
60-74 min
• Therefore WN demonstrates the
75-89 min
5.4
opposite pattern as others – as
4.5
3.8
3.5
5
3.3
2.8
2.5
2.4
2.2
1.6
90-119 min
1.2
turn time goes up, so do delays
120+ min
30 35 40 45 50 55 60 65 70 75 80 85 90
Scheduled Turn Time
SOURCE: masFlight (masflight.com)
(5 minute increments)

8. SCHEDULED VS. ACTUAL TURNS
Scheduled vs. Actual Turns at Gates
Actual time on gate averages higher than scheduled time
Mainline
Only
Scheduled Actual Difference Different factors drive a longer
Southwest 34.6 min 42.6 min +8.0 min actual time on gate than scheduled
AirTran 48.8 50.5 +1.7
JetBlue 51.2 59.1 +7.9
• Actual turn is time on gate, not the time
Spirit 53.9 57.7 +3.8
required to deplane, clean/prep, and board
Delta 58.0 67.1 +9.1
• Each airline demonstrated longer actual
Alaska 58.8 62.2 +3.4
turns than scheduled turns
American 61.4 70.4 +9.0
United 63.0 76.1* +13.1* • Drivers include strong A0 performance,
Virgin 63.3 73.6 +10.3 conservative blocks, long-haul flights
US Airways 66.1 71.2 +5.1
• However, actual turns also exhibit airline-
Mainline & specific turn time issues (WN and UA)
Scheduled Actual Difference
Regionals
United 49.5 min 58.3 min +8.8 min*
• Blue table shows mainline operations only
American 51.1 58.4 7.3
• Red table includes regional carriers
Alaska 53.0 56.6 3.6
US Airways 55.1 58.1 3.0 • Note turn performance by regional carriers
Delta 55.2 62.3 7.1
• Smaller aircraft, gate checked bags
* Reflects IT cutover
SOURCE: masFlight (masflight.com)

9. G AT E U T I L I Z AT I O N
Now let’s look at daily utilization of gates
Which carriers extract the most turns per gate?
Daily Departures per Gate Used Not surprisingly, the more carriers
June 1 through August 31, 2012
Gates with minimum 1x daily use use gates, the lower the scheduled
turn times by airline must be
Top 10
U.S. System
Airports
• The shorter the turn, the more rotations
Southwest 8.4 flights/day 7.5 flights/day the airline can squeeze out of a given gate
American 6.4 5.4
• But buffer times and density of utilization
Alaska 6.4 4.7 vary widely by carrier.
United 6.3 4.9
• Carrier gate utilization at key hubs generally
US Airways 6.3 5.2 exceeds utilization over their U.S. system
JetBlue 5.7 5.1
• At competitive hubs, higher gate utilization;
AirTran 5.6 4.4 at non-competitive hubs, gate squatting as
Delta 5.2 4.7 competitive deterrence
SOURCE: masFlight (masflight.com)

10. U T I L I Z AT I O N B Y H U B
Daily Utilization of Gates, by Hub
Surveying different carriers – daily departures per gate used, for hubs & focus cities
United Airlines Hubs Alaska Airlines Hubs American Hubs
Average Daily Deps per Gate Used Average Daily Deps per Gate Used Average Daily Deps per Gate Used
CLE 3.6 SJC 4.0 JFK 2.7
IAD 3.8 LAX 4.3
MIA 5.0
IAH 5.8 GEG 4.4
DEN 6.1 SFO 5.3 LGA 6.4
EWR 6.2 ANC 5.4 LAX 6.8
SFO 7.2 PDX 5.5
DFW 6.9
LAX 7.4 SAN 6.4
ORD 7.7 SEA 7.8 ORD 7.2
JetBlue Focus US Airways Hubs AirTran Hubs
Average Daily Deps per Gate Used Average Daily Deps per Gate Used Average Daily Deps per Gate Used
FLL 4.9 BOS 4.2 MKE 4.7
DCA 5.2
PHX 4.9
ATL 5.5
MCO 5.8
PHL 6.6
BOS 5.8
BWI 5.9
DCA 6.9
JFK 6.0
CLT 7.2 MCO 6.6
LGB 6.2
SOURCE: masFlight (masflight.com) June 1 through August 31, 2012. Gates with minimum 1x daily use

11. U T I L I Z AT I O N B Y H U B
Daily Utilization of Gates, by Hub (2)
Surveying different carriers – daily departures per gate used, for hubs & focus cities
Delta Hubs Southwest Focus There are substantial
Average Daily Deps per Gate Used Average Daily Deps per Gate Used
differences in how Southwest
MEM 2.9 PHX 7.2 operates its focus airports
CVG 3.5 MDW 7.5 Fast and consistent pace
JFK 4.0 HOU 7.5 40 minutes on gate, 20 minutes buffer
BOS 4.6 MCO 7.9 Minimal banking – rolling system
DTW 4.6 LAX 8.3 In contrast, Delta:
MSP 4.8 DAL 8.4 Uses larger aircraft at hubs –
SLC 5.2 DEN 8.5
requires longer turn times
LGA 5.4 OAK 8.5 Hub average gate departures still
below United, American, US Airways
LAX 5.8 LAS 9.5 (6x vs. 7-8x daily)
ATL 6.3 BWI 10.3 Also reflects Delta strategy of
controlling gate assets
June 1 through August 31, 2012. Gates with minimum 1x daily use
SOURCE: masFlight (masflight.com)

12. HOLD OUTS
Tight Turns and Holdouts
What percent of daytime flights likely arrive to an occupied gate or ramp area?
Delta American US Airways
DCA 16.1% DFW 20.8% PHX 15.9%
ATL 14.4% MIA 16.4% LGA 14.7%
BOS 11.2% LAS 15.2% CLT 9.9%
MCO 10.9% ORD 14.6% DCA 8.6%
PHL 10.0% CLT 14.6% DTW 8.0%
LGA 10.0% ATL 13.8% LAX 7.9%
SEA 9.0% LAX 12.6% PHL 6.7%
MSP 8.1% DTW 10.0% CMH 5.9%
LAX 8.0% BNA 10.0% ORD 3.4%
IND 7.2% DEN 9.2% EWR 3.4%
CLT 6.7% LGA 7.1% BOS 2.7%
SLC 6.5% DCA 7.0% PIT 2.4%
June 1 through August 31, 2012. Gates with minimum 1x daily use.
SOURCE: masFlight (masflight.com) Tight turn is less than 10 minutes open buffer (last out to next in)

13. HOLD OUTS
Tight Turns and Holdouts (2)
United and Southwest show similar patterns
United Southwest
Interestingly, WN is similar to
SFO 22.2% LAS 20.4%
others in the percent of flights
that hold out after landing
ORD 20.7% SEA 17.2%
Tightly orchestrated ballet at WN
LAX 18.1% STL 15.9%
IAH 14.8% BWI 14.8% Not much block padding –
Just in time arrivals
DEN 14.2% LAX 13.8%
Explains why when things go wrong,
EWR 13.0% DEN 12.8%
delays transfer downstream quickly
DFW 7.3% AUS 12.7%
LAS 7.0% SFO 11.7% Compare to United
STL 6.2% MCO 10.2%
UA has longer time on gate to absorb
MSP 6.0% SNA 9.2% late inbound delays, but has similar
buffers between flights
COS 6.0% HOU 9.1%
PDX 5.7% ABQ 8.8%
Different block strategy than WN
June 1 through August 31, 2012. Gates with minimum 1x daily use.
SOURCE: masFlight (masflight.com) Tight turn is less than 10 minutes open buffer (last out to next in)

14. U T I L I Z AT I O N V S . H O L D - O U T S
Connecting gate planning to delays
It is possible to quantitatively connect gate congestion with delay minutes
Gate Utilization vs.
A broad-based comparison of gate
% of Hold-Out/Close Waits
utilization demonstrates a positive
25.0%
correlation between gate utilization and
flights waiting for open gates
20.0%
When a flight waits for a gate, it transfers delay
minutes and is associated with increased carrier-
Hold-Outs and Close Waits
caused delay minutes
15.0%
Increase in Delay Minutes after
10.0% Inbound Flight Waits for Gate
Delay mins at Delay mins
Airline
airport by from late
5.0% (Mainline)
carrier inbound a/c
Southwest +41% +20%
US Airways +13% +4%
0.0%
3.0 5.0 7.0 9.0 Delta +2% +18%
Gate Departures per Day American +6% +18%
United +6% +7%
Close Turn Linear (Close Turn)
SOURCE: masFlight (masflight.com)

15. D E L AY G E N E R AT I O N
So where are delays generated?
Delay generation is outbound departure delay minus inbound arrival delay, by turn
Delta Airlines United Airlines Southwest Airlines
(July 2012) (July 2012) (July 2012)
LAS 3.8 ORD 3.6 DEN 4.4
SFO 1.6 SFO 2.5 LAS 4.3
LGA 1.5 LAX 2.5 BWI 3.8
SLC 0.6 IAH 1.5 PHX 3.7
MSP 0.5 EWR 1.3 MDW 3.2
SEA 0.3 DEN 0.4 HOU 2.2
DTW 0.0 SEA 0.1 LAX 0.8
DCA -0.3 IAD -0.3 OAK 0.5
ATL -0.5 SAN -0.8 STL 0.0
LAX -0.8 MCO -1.6 MCO -0.7
MCO -1.2 LAS -1.8 DAL -0.7
JFK -1.2 BOS -2.5 TPA -0.7
FLL -1.2 PDX -3.9 SAN -1.3
MEM -1.5 CLE -6.1 BNA -1.4
TPA -1.9 HNL -8.9 SJC -2.2
Flights during July 2012 (domestic + international, mainline + regional).
A positive number indicates the airport generates delays.
SOURCE: masFlight (masflight.com) A negative number indicates that the airport absorbs delays.

16. G AT E C H O I C E
Gate choice impacts on-time performance
Where a carrier gates specific flights impacts their on-time performance
Boston Logan Average Taxi-Out Times by Gate
(June-Aug 2012)
Terminal C at JetBlue has deep alleys
where push-backs block ramp access
• Inside gates (C11, C12, C26, C40-42)
have 2-3 minute longer taxi times 21.3
• C11 and C12 subject to conflicting 19.1
operations by United Airlines 19.8
• Both taxi-in and taxi-out 17.7
18.7
18.3
• This has an observable impact on 17.6
on-time performance when utilizing gates 17.8
20.5
20.4
• C11 and C12 – up to 72% on-time 17.9
20.4
17.4
• C26, C40, C42 – up to 75% on-time
18.8 18.5
• C33 to C36 – up to 79% on-time
Three months of operations, June 1, 2012 through August 31, 2012
SOURCE: masFlight (masflight.com)

17. G AT E C H O I C E
Another example of gate blocking: BWI
Southwest’s Baltimore terminal has significant ramp issues too
Baltimore (Terminal A/B)
14.6 Terminal A’s north finger creates a
12.2 15.3
blocking and delay problem for 3 gates
12.4 15.4
11.8 • Gates A6, A8 and A10 have 2-3 minutes
longer taxi-out times than others
11.9
11.8 • Notable difference in delay performance
12.1 • 66-68% summer on-time arrival rate
for flights departing from these gates
12.6
11.9 • 72-74% for flights departing other
12.4 A-gates at BWI airport
11.3 12.1 • Assignment of flights to these gates
Average Taxi-Out should be strategic, incorporating block
Times by Gate time adjustments to minimize delays
12.1
Three months of operations, June 1, 2012 through August 31, 2012
SOURCE: masFlight (masflight.com)

18. CONCLUSIONS
Conclusions: Turn Times
This project observed three different
strategies for turn times, varying based
on the gauge of aircraft and product
strategy of the airline
• Major hubs with large aircraft – 45-60 minute turns
• Major hubs with small aircraft – 30-44 minute turns
• Low-cost carriers – few turns greater than 45 mins
• What are the relevant factors?
• Aircraft size, length of haul
• Complexity of onboard product & carry-on bags
• Time of day and wheelchairs
• Drivers of actual turn times include A0 performance,
block padding and airline-specific issues
SOURCE: masFlight (masflight.com)

19. CONCLUSIONS
Conclusions: Gate Utilization
Gate utilization depends on real estate
controlled, competitiveness of market,
and banking strategies
• Airlines with shorter turn times generally extract
more departures each day from gate assets
• However the converse isn’t always so – carriers with
fewer gate departures may just squat on assets to
deter competition, particularly from efficient LCCs
• Airline utilization by hub varies widely. Highly
banked international hubs (JFK, IAD) often have the
lowest daily utilization. Also, dying hubs (CLE, MEM)
• Southwest clearly emphasizes gate utilization to
maximize efficiency. Combined with very short turn
times, this creates operational bottlenecks when
operations go off-track.
SOURCE: masFlight (masflight.com)

20. CONCLUSIONS
Conclusions: Delay Impact
Utilization, turn times, and even gate selection impact on-time
performance and necessitate incorporation into block planning
• Hold-outs and taxi-in delays can impact up to 20% of operations at a busy hub.
Based on carriers analyzed, on average 10% of day flights wait for gate or ramp
congestion to clear.
• You’d expect Southwest to hold out, but they don’t any more than others
• As scheduled turn time increases, inbound delays are absorbed and departure delays
decrease. This is true for all carriers except Southwest (where longer turns are
programmed at congested airports that generate delays)
• Delay generation by airport varies. You’d expect NYC to generate delays, but carriers
build NYC delays into scheduled turns. Chicago and San Francisco, in contrast, have
more unexpected delays that drive higher net generation.
• Gate choice matters. The difference in taxi-in and taxi-out times for gates at the end of
a pier can be 2-3 minutes shorter than locations at the base of a pier.
• This can make a significant difference in on-time performance!
SOURCE: masFlight (masflight.com)