NEW YORK FLIGHT DELAYS

HAVE THREE MAIN CAUSES, BUT MORE WORK 

IS NEEDED TO 

UNDERSTAND THEIR NATIONWIDE EFFECT 

Federal Aviation Administration

Report Number AV-2011-007

Date Issued: October 28, 2010
U.S. Department of

Memorandum

Transportation

Office of the Secretary

of Transportation

Office of Inspector General

Subject: ACTION: New York Flight Delays Have Three 

Main Causes, but More Work Is Needed To

Understand Their Nationwide Effect 

Federal Aviation Administration

Report Number AV-2011-007

Date: October 28, 2010

From: Lou E. Dixon

Principal Assistant Inspector General 

for Auditing and Evaluation

Reply to 

Attn. of: JA-1

To: Federal Aviation Administrator

During the summer of 2007, the United States experienced record-setting flight 

delays, with nearly one in three domestic flights either delayed or cancelled. The 

New York region’s three largest airports—Kennedy, LaGuardia, and Newark—led 

the Nation with over 40 percent of arriving flights either delayed or cancelled. 

Although the overall situation improved somewhat in 2009, this region continued

to report nearly one-third of its flights as delayed or cancelled. Such delays not 

only pose a significant problem for air travelers in the New York region but also 

affect passengers flying to other parts of the country. 

The Chairman of the House Subcommittee on Aviation requested that we 

(1) determine the principal causes of flights delays in the New York region and 

(2) identify the corresponding effect of these delays nationwide. We conducted 

the audit from June 2009 through August 2010 in accordance with government 

auditing standards prescribed by the Comptroller General of the United States. 

We based our observations and conclusions on interviews with Federal Aviation 

Administration (FAA), air carriers, and the Port Authority of New York and New 

Jersey as well as our analysis of air traffic and delay data collected by FAA and 

the Department of Transportation’s (DOT) Bureau of Transportation Statistics

(BTS). Exhibit A details our audit scope and methodology.
2

RESULTS IN BRIEF

Flight delays have been a significant problem for the New York region for many 

decades.1 While various factors have contributed to this problem, the three 

principal causes are a small and densely occupied airspace, limited capacity 

among the region’s three main airports, and continued growth in air traffic. FAA 

first attempted to manage flight delays at LaGuardia, Newark, and Kennedy in

1970 using flight limits (or caps) under the High Density Rule,2 but those limits 

were phased out between 2000 and 2007.3 While the phase-out had noticeable 

benefits, such as reduced air fares and service to new markets due to increased 

competition, it also led to record levels of flight delays for the New York region. 

To prevent delays from getting worse, FAA reintroduced flight caps in 2008. Yet, 

these new caps have done little to reduce delays at New York because FAA based 

the caps on the airports’ 2007 operating levels—despite record delays—and did 

not establish an on-time performance target. For flight caps to have more success 

in preventing delays from again rising to record levels, FAA will need to 

reexamine them, basing them on realistic airport operating conditions, air carrier 

scheduling practices, and an acceptable rate of delay.4

While there is substantial agreement within the aviation community that New 

York delays have a propagation (i.e., ripple) effect across the Nation, the extent 

and nature of their impact are largely unknown.5 FAA and others’ attempts to

measure the ripple effect have been hampered by the volume, complexity, and 

limitations of existing flight data and analytic methods as well as insufficient 

leadership and coordination among research groups studying this issue. Although 

FAA has initiated two projects to measure delay propagation, additional work 

remains before either will prove to be useful analyses of delay propagation. As a 

result, no one fully understands the impact of New York flight delays nationwide, 

whether New York airports absorb or generate delays, or what other airports are 

affected and to what degree. Gaining a greater understanding of the dynamics6

1 The U.S. Department of Transportation (DOT) defines a flight as delayed when it arrives more than 15 minutes after 

its published arrival time.

of 

flight delays and their nationwide impact will aid FAA’s efforts to reduce flight 

2 In 1969, FAA imposed flight limits through the High Density Rule, due to concerns with aviation safety, congestion, 

and flight delays at New York and other large airports. The High Density Rule established limits on the number of 

hourly flight operations at all three major New York area airports (and Chicago O’Hare and Reagan National), 

although Newark was soon exempted in 1970. 3 The Wendell H. Ford Aviation Investment and Reform Act for the 21st Century (AIR-21), Pub. L. No. 106-181

(2005). This law called for the phase-out of the High Density Rule at LaGuardia and Kennedy airports by granting 

exemptions beginning with passage of the law on April 5, 2000, and eventual repeal of the rule at the two airports 

effective January 1, 2007. 4 A rate of delay is the percent of flights delayed. 5 Delay propagation refers to the ripple effect of an initial delay on subsequent flights of the same aircraft. 6 To measure dynamics of flight delays, various factors need to be considered, including cause and location of initial 

delay, duration of delay by type of cause, aircraft turnaround time (i.e., the duration of ground time between an 

aircraft’s scheduled arrival and next departure), and delay absorption or generation (i.e., an airport’s tendency to 

reduce or increase an aircraft’s amount of delay).
3

delays and congestion, better manage air traffic, and improve investment 

decisions.

We are recommending that FAA reexamine its flight caps, enhance existing flight 

data, and develop a viable methodology for understanding the propagation effects

of flight delays.

BACKGROUND

For more than 40 years, the New 

York region has comprised one 

of the most congested and 

delayed aviation areas in the 

United States. During a typical 

summer day, more than 

1,400 aircraft fly through the 

3 main New York airports (i.e., 

Kennedy, LaGuardia, and 

Newark), and almost a third of 

those aircraft fly through 

multiple times. These aircraft

complete a total of 5,400 flights 

across the country and around the 

globe, landing at 122 domestic 

airports and 52 foreign countries

(see figure 1).

This high flight volume, coupled with dense airspace and limited capacity, have

resulted in the 3 New York airports experiencing the highest delay rate among the 

55 major U.S. airports. The situation has worsened over the last decade, with 

35 percent of flights delayed in 2008 compared to the already high 29 percent in 

1999.7

Since 2000, we have issued a number of reports and testified before Congress on 

the growing number of flight delays, air carrier customer service, and air traffic 

congestion both in New York and nationwide. Our most recent report, issued last 

year, examined FAA’s progress in implementing the New York Aviation 

Rulemaking Committee’s (ARC) 77 initiatives for reducing delays and congestion 

These delays not only affect aircraft travelling to and from the region but 

can also create a ripple effect as those aircraft fly throughout the Nation.

7 Our analysis focused on operations and delays at the three largest New York airports from 1999 through 2008. In 

1999, FAA had not yet begun phasing out flight limits at Kennedy and LaGuardia; subsequent data through 2008 

show the effects of the final statutory removal of the flight limits in 2007 and the first year of newly reimposed limits

by FAA at Kennedy and Newark.

Figure 1. Typical Daily Flight Itineraries for Aircraft 

Going Into and Out of Three New York Airports

Source: FAA and BTS
4

in the New York area.8

PRINCIPAL CAUSES OF NEW YORK FLIGHT DELAYS ARE 

DENSE AIRSPACE, LIMITED AIRPORT CAPACITY, AND HIGH AIR 

TRAFFIC DEMAND

We concluded that many of the ARC 77 initiatives had not 

been fully implemented or were used infrequently and thus had little impact on the 

delay situation. (See exhibit B for a full list of our reports and testimonies related 

to flight delays in the New York region.)

The principal causes of New York flight delays are crowded airspace, airport 

capacity constraints, and continued growth in air traffic. Together, these factors 

have caused the New York 

airports to experience higher 

levels of flight delays than 

the Nation’s other large 

airports (see figure 2). The 

phase-out of flight limits or 

caps (i.e., FAA’s High 

Density Rule) between 2000 

and 2007 at LaGuardia and 

Kennedy9 contributed to the 

growth in air traffic and 

subsequent congestion and 

delays. FAA’s efforts in 

2008 to mitigate delays by

reinstating flight caps at 

Kennedy and Newark,

however, yielded little improvement.10

8 OIG Report Number AV-2010-003, “Status of the Aviation Rulemaking Committee’s 77 Initiatives for Reducing 

Delays in the New York Area,” October 21, 2009. OIG reports are available on our website: 

This is because FAA based its caps on the 

maximum capacity experienced at the airports during 2007—a year with record 

delays—and did not use an on-time performance target (i.e., acceptable rate of 

delays) for determining airports’ realistic capacity. While delays have declined 

during the recent economic recession, flight volume and delays will likely return 

as the economy recovers.

www.oig.dot.gov. 9 While this action led to an 8-percent increase in flights serving New York, the actual number of passenger seats 

declined by 0.6 percent as carriers substituted larger aircraft with regional jets. 10 FAA had already imposed new flight limits at LaGuardia in 2001, because the phase-out of the airport’s caps in 2000 

led to rapid growth in flights and delays.

Figure 2. Flight Delays at the 3 Primary

New York Airports Versus 52 Other Large Airports

FY 1998 to FY 2009
5

Principal Causes of the New York Region’s Flight Delays

Dense New York Airspace: New York’s airspace is one of the densest in the 

country due to the close proximity of the three major airports and the high volume 

and complexity of flight operations. Kennedy, LaGuardia, and Newark airports 

are compressed into less than 100 square miles—an area slightly larger than 

Washington, DC. This close proximity creates a high degree of operational interdependence among the three airports, with changes at one airport frequently

impacting flight operations (both on the ground and in the air) at the other two. 

For example, changing weather 

conditions (e.g., wind patterns) may 

require one airport to use a different 

runway configuration, which in turn 

can impact the surrounding airspace 

and aircraft operations at the other 

two airports. The congested airspace 

also requires close attention to 

spacing between aircraft, which can 

add further time (and delays) to 

affected flights. Thus, it is not 

surprising that nearly two-thirds of 

flight delays at the three New York airports are attributable to weather and high 

volume (congestion)—twice that of the other 52 largest airports that FAA tracks 

(see table 1). 

Further, the three New York airports together represent the most heavily used 

combination of airports in a single metropolitan area in the Nation. During a 

typical summer day, more than 3,500 flights—involving 1,400 aircraft—begin or 

end at 1 of these airports. Moreover, the New York Terminal Radar Approach 

Control (TRACON), which manages flights into, out of, and through the New 

York region, handles nearly 2 million flights per year, second only to the Southern 

California TRACON.11 Likewise, the New York Air Route Traffic Control Center

(ARTCC)12 manages the densest en route airspace on either side of the Atlantic.13

11 TRACONs are FAA facilities that guide aircraft approaching and departing airports generally within a 30- to 50-mile 

radius up to an altitude of 10,000 feet as well as aircraft that may be flying through that airspace.

In addition to the flights landing at and taking off from the three major airports, 

12 ARTCCs control aircraft primarily during the en route (i.e., high altitude) phase of the flight, and the New York 

ARTCC is responsible aircraft flying over five states and much of the North Atlantic. 13 The calculation of New York ARTCC’s airspace density does not include the oceanic portion.

Table 1. Comparison of Delay Causal 

Factors June through August 2009

Causal Factor

3 NY 

Airports

52 Other 

Airports

Weather 51% 21%

Volume 10% 6%

Late Arriving Aircraft 20% 36%

Air Carrier 15% 26%

Other 4% 11%

Total 100% 100%

Source: OIG analysis of DOT data
6

the New York TRACON and ARTCC handle aircraft using more than a dozen 

nearby airports as well as those flying through the New York airspace.14

The rapid growth in regional jet operations has further compounded the density 

and complexity of the New York airspace. Since 1999, air carriers have increased 

their use of regional jets (i.e., 35-100 seats) by 500 percent at the New York 

airports, replacing nearly all turboprop aircraft as well as some larger jets.15

Limited Airport Capacity: Due to significant space and operational constraints,

Kennedy, LaGuardia, and Newark are severely limited in the number of flights 

that they can safely and efficiently accommodate (i.e., capacity). Although new

technology and procedures can enhance airport capacity, new runways typically 

bring the greatest increase. Yet, the last new runway added at any of the New 

York major airports occurred at Newark in the early 1970s, and there are no plans 

to add any new ones. For example, an August 2007 Port Authority of New York 

and New Jersey (Port Authority) study determined it was not feasible to construct 

a new runway at Kennedy, although it proposed several smaller capacity 

improvements (e.g., additional runway extensions and taxiway improvements). 

The study concluded that any new runway project would not only be very costly 

and controversial but also extremely difficult to advance as it would be built 

within a protected environmental area. In contrast, 17 other major airports across 

the Nation have added new runways since 1999. These include busy airports such 

as Chicago O’Hare, Atlanta Hartsfield, Boston Logan, and Washington Dulles. 

While the existing New York airspace may be used more efficiently in the future 

due to FAA’s ongoing airspace redesign, the Agency states that this project will

not increase airport capacity.

The 

increased use of regional jets, however, was not without some negative 

repercussions, as the smaller jets—unlike turboprops—occupy the same airspace 

and use the same runways as larger jet aircraft. In effect, the influx of regional jets 

has further saturated New York’s already crowded airspace, routings, and 

runways, while those formerly occupied by turboprop aircraft are now used less.

Increases in Air Traffic Demand: Over the last decade, flight demand in the 

New York region has grown considerably. Between 1999 and 2008, the number 

of flights departing the New York area increased by 8 percent (from 567,000 to 

612,000)—the equivalent of adding a mid-sized airport’s flight operations (e.g., 

Albuquerque or New Orleans) without building a single new runway. This 

increase was due to various factors:

14 Congestion in the New York region is not a problem involving only the commercial air carriers. For instance, 

general aviation accounts for less than 3 percent of the flight activity at the three New York airports, but represents 

about 25 percent of New York TRACON’s total operations. 15 Air carriers decided to use regional jets because they are faster and more cost effective than turboprop aircraft, and in 

2000 the Congress exempted such aircraft from then existing flight limits at LaGuardia and Kennedy. 
7

Emergence of JetBlue Airways in the New York Region: In 2000, JetBlue

inaugurated operations at Kennedy airport and subsequently added flights at 

both Newark and LaGuardia. Between 2000 and 2008, JetBlue’s departures 

from the three New York airports increased by more than 1,000 percent (5,071 

to 64,881), with the greatest increase at Kennedy. 

Establishment of Delta Air Lines International Hub at Kennedy: In late 2006, 

Delta Air Lines established an international hub at Kennedy, and the carrier’s 

scheduled departures at the airport jumped by 46 percent (from 43,400 to 

63,400) the next year.16

Phase-Out of FAA’s High Density Rule at LaGuardia and Kennedy: In 2000,

after Congress voted to phase out the High Density Rule flight caps, air service 

began between New York and several new domestic and international markets, 

and air fares in the New York region declined. By the time the caps had 

expired at LaGuardia and Kennedy in 2007, both airports had experienced a 

sizable increase in flight operations.

 The creation of Delta’s Kennedy hub was made 

possible by the ending of FAA’s High Density Rule in 2007.

17

Resulting Increase in Flight Delays: The increase in flights over the last decade, 

coupled with New York’s already dense airspace and constrained airport capacity, 

resulted in a 46-percent increase in the number of flights delayed. As shown in

figure 3 below, between 1999 and 2008, the number of on-time flights remained 

fairly constant at about 100,000 per summer. However, as the number of flights 

grew over the same time period so did the number of delays. The net effect, 

therefore, was that any new growth in flight activity translated exponentially into a 

higher number and rate of delays. Conversely, as the number of flights declined 

(i.e., 2002-2003 and 2009) so did the number and rate of delayed flights.

For example, during the summer of 

2007, the average number of daily flights in the New York area increased by 

about 6 percent (3,100 to 3,300 flights) over the previous summer (22 percent 

growth at Kennedy alone). 

16 The increase in Kennedy flight operations also forced FAA to change its management of air traffic (and delays) in 

the New York area. Before the increase, FAA favored operations at Newark and LaGuardia; after the increase, the 

Agency had to balance use of the airspace among the three airports. This, in turn, resulted in additional constraints 

on Newark and LaGuardia flight operations. 17 Starting in 2000, AIR-21 (Pub. L. No. 106-181) also permitted exemptions to slot controls at LaGuardia for new 

entrants and regional jet operators, resulting in a 26-percent increase in scheduled flights and a 525-percent increase

in delays from November 1999 to November 2000. In 2001, FAA attempted to alleviate the resulting gridlock by

reducing the number of new flights, limiting the overall growth to about 14 percent. These caps remained in effect 

beyond the legislated termination of the HDR in 2007.
8

FAA’s Current Flight Caps Are Not an Effective Solution for Reducing 

Delays at New York Airports

Following the record delays of summer 2007, FAA reimposed hourly flight caps at 

Kennedy and Newark and maintained caps at LaGuardia in 2008. However, 

FAA’s goals were to keep delays from getting worse and to reduce their severity,

but not to reduce the number or rate of delays.18

18 FAA’s goals were to reduce the average minutes of airport departure delay at Kennedy, keep arrival and departure 

delays from increasing at Newark, and reduce the number of severe delays (i.e., greater than 1 hour) at both airports.

 In effect, FAA set the new caps 

near the airports’ maximum capacity in optimum weather conditions and then 

allowed air carriers’ schedules to exceed those caps during certain time periods. 

As a result, there was little meaningful improvement in New York’s delay 

situation during the summer of 2008. In contrast to FAA’s efforts, the three major 

London airports set their flight caps with consideration of seasonal weather 

variations and a performance target that helps reduce the rate of delays. While 

FAA recognizes that its caps may be too high and has taken steps to improve 

them, much work remains to ensure the caps can effectively prevent delays from 

again rising to record levels.

Figure 3. Corresponding Increases in Flight Operations and Delays

(June through August at Kennedy, LaGuardia, and Newark Airports)

0

25,000

50,000

75,000

100,000

125,000

150,000

175,000

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

On-Time Flights Delayed Flights

Trend in 

Total Flights 

and Delays

Trend in OnTime Flights

Source: OIG analysis of FAA data
9

FAA Designed the 2008 Flight 

Caps with Limited Goals: In 

calculating the caps for 2008,

FAA used a model to identify the 

number of hourly flights that 

would achieve its limited delayreduction goals. The model was 

based on the highest hourly 

capacity experienced at the New 

York airports during 2007, when 

delays were at their highest. As

shown in table 2, the resulting 

caps are near the airports’ maximum capacity19 in optimum weather conditions,

despite the fact that nearly two-thirds of New York delays occur as a result of poor 

weather or high volume of flight activity.20

FAA’s decision to allow air carrier schedules to exceed the caps during certain 

time periods during the day exacerbated the delay situation in New York. To 

ensure the caps were enacted prior to the summer of 2008, FAA negotiated with 

the air carriers to curtail their planned increases in summer flights and to shift 

flights to less congested times.

Moreover, FAA did not establish a 

maximum rate of delay as a goal to use in calculating flight caps. Such a goal 

would help determine the number of hourly operations an airport could reasonably 

sustain without exceeding that goal. In addition, the goal could also be a 

benchmark toward which passengers can base expectations and the Agency and 

airlines can manage and measure their performance.

21 As part of the negotiations, FAA agreed to 

accommodate air carrier scheduling practices, by allowing them to exceed flight 

caps during certain 15- and 30-minute periods—as long as the hourly caps were

generally achieved. Figure 4 below shows an example of how Kennedy’s

operations exceeded flight caps on one summer day in 2008. Even in optimal 

weather (VFR conditions), these peaks—which in some cases are nearly twice 

Kennedy’s stated capacity—can produce long lines of aircraft waiting to take off 

and taxi-out times approaching 1 hour, the longest of any airport in the Nation.22

19 FAA generally allocated 81 operations per hour for scheduled flights at both Kennedy and Newark and 75 at 

LaGuardia—as well as 2 nonscheduled operations per hour at both Kennedy and Newark and 6 at LaGuardia. 20 Generally, the number of departures and arrivals an airport can handle are contingent upon weather conditions 

specified by FAA’s Visual Flight Rule (VFR) and Instrument Flight Rule (IFR) capacity rates. If visibility levels 

fall below the minimum VFR conditions, then IFR conditions govern flight operations, thus reducing airport 

capacity. 21 Rather than impose the caps under a lengthy rulemaking process, FAA sought to achieve air carrier acceptance of the 

caps and ensure the carriers had sufficient time to begin marketing summer flights to the public. 22 In 2010, FAA continues to allow air carriers to schedule flights in excess of the desired caps, although the excess is 

slightly below that experienced in 2008.

Table 2. Comparison of Total Hourly Capacity 

Measures with Flight Caps at Three New York 

Airports During Summer 2008

Airport

Airport 

Capacity 

In Poor 

Weather 

Conditions

(IFR) 

Caps

(Scheduled 

and 

Unscheduled)

Airport 

Capacity 

In

Optimum 

Conditions

(VFR)

Kennedy 64-67 83 75-87

LaGuardia 69-74 81 78-85

Newark 61-66 83 84-92

Source: OIG analysis of FAA data
10

Figure 4. Comparison of Flight Schedules with Various Capacity Measures

at Kennedy (June 18, 2008)

By setting the reimposed caps near the airports’ maximum capacity and permitting 

scheduling peaks, FAA achieved its limited goals for the summer of 2008 with 

only modest reductions in the both the average length of airport departure delays 

and in the number of flights delayed by more than 1 hour. However, since FAA’s

goals did not include improvements in the delay rate and the average duration of 

delayed flights, New York again experienced severe flight disruptions in the 

summer of 2008, with more than 40 percent of New York arrivals delayed or 

cancelled and arrival delays averaging 71 minutes. Although delays have since 

declined due to a drop in air traffic, once the economy recovers and flight volume 

returns, delays will likely rise again and increase passenger dissatisfaction with air 

travel.

FAA Efforts Could Benefit from London’s Air Traffic Control Lessons 

Learned: To gain an international perspective on New York, we observed how 

flight caps are planned at London’s three major airports (Gatwick, Heathrow, and 

Stansted). These airports together serve a greater number of passengers than the 

three major New York airports but experience a lower rate of flight delays. In 

London, airports, air carriers, and the air traffic control organization coordinate to 

reach consensus on the number of flights that can be accommodated (caps) 

without exceeding an acceptable delay target. To determine a realistic hourly cap, 

these organizations also base the capacity of the London metropolitan airports on 

both winter and summer weather conditions—not year-round optimal conditions 

as is the practice for New York. By taking these steps, the London airports 

experience about a 20 percent lower rate of delays than their New York 
11

counterparts by operating 28 percent fewer flights. Yet, London airports handle a

greater number of passengers because air carriers are using larger aircraft. 

FAA’s Ongoing Efforts To Improve Flight Caps: FAA recognizes that its 

reimposed flight limits at the three New York airports may be set too high and has 

taken steps to improve them. In January 2009, FAA announced its plan to reduce 

the number of hourly flights permitted at LaGuardia from 75 to 71 operations,

acknowledging that the caps caused significant delays when operating conditions 

deteriorated (e.g., during poor weather or periods of excess demand). FAA has 

also been recalling and retaining unused and or voluntarily surrendered slots at 

Kennedy and Newark where they were negotiated in excess of FAA’s desired 

hourly caps.23

FAA LACKS THE ANALYTICAL CAPABILITY TO DETERMINE THE 

NATIONWIDE EFFECT OF NEW YORK FLIGHT DELAYS 

In October 2009, FAA extended the Kennedy and Newark flight 

caps for 2 more years and announced that it would reduce flight caps at those 

airports if conditions warranted. However, further reducing flight caps or 

restricting scheduling practices to smooth schedule peaking within individual

hours will be difficult to achieve due to air carriers’ desire for unlimited access to 

the airports and passenger demands for greater service to and from the New York 

region. To prevent delay rates from again rising to record levels, FAA will need 

to reexamine its flight caps, basing them on realistic airport operating conditions, 

air carrier scheduling practices and an acceptable rate of delay.

While there is wide agreement within the aviation community that New York 

delays have a propagation (i.e., ripple) effect on the rest of the Nation, we found 

the actual extent and nature of this impact remains largely unknown. FAA

currently lacks the ability to measure the propagation effect of New York flight 

delays, and others in the aviation community have only developed fragmentary 

estimates. Various challenges have hampered FAA and others within the aviation 

community in measuring this “ripple effect.” These include the sheer volume, 

complexity, and limitations of existing flight data and analytic methods as well as 

insufficient FAA leadership and coordination of the various groups researching 

this issue. FAA has initiated two projects to measure delay propagation, although 

both need further development before they will prove useful in the analysis of 

delay propagation. Thus, no one fully understands how or to what degree New 

York delays impact flights nationwide. A complete understanding of the 

dynamics of flight delays and their nationwide impact would aid FAA in its efforts 

to manage air traffic, and make sound investment decisions on future aviation 

infrastructure improvements. 

23 FAA has not forced air carriers to relinquish slots; instead, it is relying on voluntary surrender of slots above the new 

limits, whereupon they would be retired by the Agency.
12

Little Is Known as to Actual Nationwide Impact of New York Delays

While it is generally understood that New York delays affect other flights, FAA 

has not reported on this effect, and researchers in academia and the aviation 

industry have provided, at best, only limited information on it. For example, in 

April 2010, the Air Transport Association (ATA) noted that the three New York 

airports represent nearly half of all flight delays among the Nation’s largest 

airports. However, the ATA analysis only expresses what portion of nationwide 

delays occur as a result of congestion at the New York airports and airspace

(which includes Philadelphia), not their propagation effect. In addition, at a

November 2007 White House press conference, then-Secretary Mary Peters stated 

that “... three-quarters of the flight delays are because the plane went into, out of, 

or through the New York airspace....” This figure, however, addresses only 

chronically delayed flights, a small subset of all flight delays.24

Various Factors Hamper Efforts To Measure the Nationwide Effect of

New York Flight Delays

Neither these 

estimates nor other industry and academic research answers a number of important 

questions—such as where the delays originated (locally or elsewhere), whether the 

New York airports absorb or generate delays, what other airports are affected and 

to what degree, and how air carrier scheduling decisions might cause or alleviate 

the propagation effect. Any effort to fully understand the propagation effect of 

New York delays will have to overcome the limitations of earlier efforts as well as 

a number of other challenges.

In order to understand the propagation effect of flight delays, FAA and other 

aviation research groups face several key challenges. These include developing 

analytical methodologies for measuring delay propagation; overcoming limitations

in existing delay data sets; and improving coordination between FAA, BTS, and 

other aviation and research groups. Until these challenges are overcome, no one 

will fully understand the impact of flight delays on the rest of the Nation.

Analytical Complexity. The sheer volume and complexity of flight delay data 

pose a significant mathematical and data management challenge. Before an 

analysis of delay propagation can begin, FAA and others must assemble more 

than 10 million annual flight records—each with multiple arrival and departure 

times and causes of delay data elements—into a database of daily aircraft 

itineraries. In addition, they must develop methods to compile, extract, and 

analyze the delay characteristics and follow the flow of initial delays to their 

ripple effect.

24 The variance in these two estimates is due to the differing methodologies used. For example, the three-quarters 

figure covered only those flights that were chronically delayed 70 percent or more over a 3-month period—a small 

subset of all flight delays. In comparison, the ATA study was restricted to those flight delays at the 35 largest U.S. 

airports and excluded delays caused by air carrier action (e.g., mechanical, customer accommodation, or crew).
13

Data Limitations. Of the two main databases used by FAA to track flight and 

delay information, neither provides all the necessary information to fully 

measure delay propagation.25 A critical component of determining the delay 

propagation effect is the ability to track each aircraft’s daily movements using 

its unique tail number. Unfortunately, 1 database, maintained by BTS, only 

contains aircraft tail numbers for the 19 largest domestic passenger air carriers,

representing about two-thirds of the flights that could be analyzed. In contrast, 

a second database, maintained by FAA, contains more comprehensive 

information on all passenger and cargo aircraft operating both domestically and 

trans-border, but has tail numbers for only 40 percent of these aircraft. There 

are also inaccuracies in the BTS data, though BTS hopes recently implemented 

validation edits will largely identify and correct air carrier reporting errors.26

Insufficient Leadership and Coordination. To date, FAA has not exercised the 

leadership required for bringing the air carriers, academia, and other aviation 

research groups together to develop viable analytic methodologies, useful 

database structures, or common terms of reference. These organizations’ input 

and analytic resources are required to achieve a full understanding of the delay 

propagation phenomena and to develop workable applications for aviation 

stakeholders. In the absence of FAA’s leadership, these groups have made 

some individual efforts at measuring delay propagation, but the resulting 

information has been largely theoretical in nature or of limited application.

FAA Has Only Recently Begun To Examine Delay Propagation Effects

Although FAA has two projects for measuring and tracking delay propagation

(both in New York and elsewhere), these efforts will require more work before 

proving useful in analyzing delay propagation. For example, one project, 

managed within FAA, is exploring delay propagation as a way to improve FAA’s

air traffic management nationwide. By analyzing the delay pattern of aircraft as 

they move about the country, FAA would be able to identify where a delay began 

and how it impacted later flights. However, the project’s methodology may 

undercount initial delays and overcount delay propagation because it estimates 

them through mathematical calculation rather than using actual carrier-reported 

causal information. For example, an aircraft could experience an initial delay on 

one flight leg due to a mechanical problem and a delay on the next leg due to 

weather. Under this methodology, FAA could categorize this example as one 

delay event (first leg) with a propagated delay (second leg), instead of two 

25 Although sufficient data exist for FAA and others to continue the study of delay propagation and apply results, this 

effort would be improved if existing data limitations were addressed. 26 Questions regarding the accuracy of air carrier reported causes of delay have caused some FAA officials to be 

skeptical in accepting the results of delay analysis or reluctant to consider delay propagation in other than theoretical 

terms. 
14

separate delay events. This project also only measures the minutes of delay 

propagation, not the number of subsequently delayed flights.

A second project, undertaken by MITRE Corporation27

Unless FAA Develops Viable Methods To Analyze and Understand 

Delay Propagation, It Will Continue To Miss Opportunities To Improve 

Air Traffic Management and Investment Decisions

under contract to FAA, is 

exploring delay propagation to help improve calculation of the nationwide benefit 

from individual airport capital improvement projects. Under this application, 

delay propagation data could be used to quantify the ripple effect of delays at an 

airport and, thus, determine the potential national (multiplier) impact of delayreducing investments at that airport. This second effort also relies on calculating

flight delays and contains similar limitations as the first project. Further, FAA 

would need to expand the scope of this project from identifying a multiplier effect 

(e.g., minutes of delays) to one that studies the specific characteristics of New 

York delays and their ripple effect (e.g., causes, duration, and locations).

Using detailed and comprehensive information on flight delay propagation would 

help FAA identify the location of an initial delay and its effect nationwide. Doing

so would also help the Agency discern between delays that originate at an airport 

and those that are merely the ripple effect of delays originating elsewhere. 

Moreover, a better understanding of New York’s impact on the rest of the Nation 

would help FAA achieve the following specific benefits:

Congestion Relief: Based on information about initial causes, FAA could 

more accurately identify and then address underlying problems leading to 

increased congestion. Moreover, it could identify which air carrier practices

(e.g., scheduling and turn-around times) contribute to or reduce congestion and 

delays at specific airport or on specific routes.

Improved Air Traffic Management: FAA could better understand how 

certain delays affect flights locally and nationwide, as well as the effect of its 

air traffic management initiatives such as ground stop and ground delay 

programs.28

More Informed Investment Decisions: Propagation data could improve 

investment decisions by giving FAA and airports more complete information 

on the potential benefits from delay reduction and/or capital improvement

27 The MITRE Corporation, a not-for-profit organization, manages the Center for Advanced Aviation System 

Development, a federally funded research and development center supporting FAA efforts to address various 

aviation challenges, such as reducing flight delays and managing air traffic. 28 A ground stop is a halt of departures at origin airports that are destined to a specific, congested airport. A ground 

delay program holds flight at their origins and delays the departure times to slow the pace of arrivals at a congested 

airport.
15

projects. For example, FAA could better prioritize where to deploy new 

equipment and procedures (e.g., RNAV)29

CONCLUSION

that would assist FAA in managing 

air traffic and help reduce delays. In other cases, understanding the 

propagation effect of delays would enable FAA to evaluate whether delayreducing investments at a particular airport would also have an impact in 

reducing delays elsewhere in the National Airspace System.

The New York region serves as the key domestic and international aviation hub

for the United States. In 2007, over 1.2 million flights passed through the 3 main 

airports, transporting 108 million passengers and 2.6 million tons of cargo. Yet, 

about 35 percent of flights are delayed each year, which cost New York 

passengers and air carriers an estimated $2.6 billion in 2008.30

RECOMMENDATIONS

 These costs, 

however, do not stop just in New York, but ripple throughout the Nation. While

delays in the New York area have dropped over the last 2 years, given the region’s 

constrained capacity, they are likely to increase again as the global economy 

improves and air travel demand returns. For flight caps to have any success in 

helping prevent delays from again rising to record levels, FAA and key aviation 

stakeholders will need to reexamine flight caps, basing them on more realistic 

airport operating conditions and acceptable delay rates. Furthermore, gaining a 

fuller understanding of delay propagation will aid FAA in its efforts to reduce 

flight delays and congestion, better manage air traffic, and make better investment 

decisions.

We recommend that FAA:

1. Reexamine flight caps at Kennedy, LaGuardia, and Newark airports, basing the 

caps on more realistic airport operating conditions, air carrier scheduling 

practices, and a goal towards reducing delays to an acceptable rate. In 

considering an acceptable rate and length of delay, FAA should incorporate the 

views of air carriers, the airport operator, and passenger groups as well as

lessons learned from other slot-controlled airports.

2. Establish a working group of air carriers, academia, and other aviation research 

organizations to enhance the understanding of delay propagation (e.g., develop

viable analytic methodologies, useful database structures, and common terms 

of reference).

29 RNAV (Area Navigation) is a satellite-based aircraft navigation system providing more direct airport routings 

compared to the conventional, ground-based navigation where aircraft are routed from point to point to the airport. 30 Source: Grounded - The High Cost of Air Traffic Congestion, February, 2009, Partnership for New York City.
16

3. Enhance existing flight delay data by obtaining aircraft tail numbers for 

domestic and international flight operations of U.S. air carriers in order to 

better study and manage the propagation effect of flight delays.

4. Complete development of a viable methodology for measuring the dynamics of 

flight delays at New York (as well as other U.S. airports) and their propagation

nationwide. This methodology should include the ability to measure both the 

amount of delay time being propagated and the number of subsequent flights

being impacted.

AGENCY COMMENTS AND OFFICE OF INSPECTOR GENERAL 

RESPONSE

We provided FAA a draft copy of this report on August 25, 2010, for comment 

and received the Agency’s response on September 29, 2010. FAA fully concurred 

with recommendation 2 and partially concurred with recommendations 1, 3, and 4. 

Overall, FAA’s response meets the intent of recommendation 2 but only partially 

meets the intent of recommendations 1, 3, and 4. Specifically:

For recommendation 1, FAA stated it had already incorporated many of our

recommendations when it established the initial flight caps for Kennedy and 

Newark. However, this does not address our main points that those flight caps 

did little to reduce delays and that FAA established them without an on-time 

performance target. Therefore, FAA must ensure its current evaluation of New 

York flights caps (a) includes a goal of limiting arrival delays to a more 

acceptable rate and length (i.e., below those experienced during the summers 

of 2007 and 2008) and (b) provides passenger groups with greater 

opportunities to participate in this process.

For recommendation 2, FAA proposed to host or participate in a forum, within 

1 year, to enhance the Agency’s delay propagation methodologies. While this 

is an important first step, our report points out that FAA will also need to 

provide ongoing leadership in developing and coordinating stakeholders’ (e.g., 

airlines and academia) research in this field to develop a better understanding 

of delay propagation and workable applications for the industry. 

For recommendation 3, FAA stated it would pursue data on aircraft tail 

numbers for international flight records. However, FAA still needs to explain 

how it will acquire aircraft tail numbers for those domestic airlines that do not

currently report this information to the Bureau of Transportation Statistics.

For recommendation 4, FAA stated it had developed 	



methodology for measuring delay propagation. We commend FAA’s efforts in
17

this area and recognize that this type of analysis is an evolving science. 

However, we note that the methodology cited in FAA’s response only 

measures delay propagation to assess the benefits of future airport capital 

improvement projects—it does not measure the ripple effects of New York 

delays and their characteristics (e.g., causes, number, duration, and location).

We request that FAA clarify how it intends to develop these data and 

incorporate them in future improvements to its delay propagation 

methodology.

ACTIONS REQUIRED

FAA provided acceptable actions and timeframes for recommendation 2, and we 

consider it resolved but open until the planned actions are completed. We request 

that FAA provide our office with a response clarifying its planned actions and 

addressing the issues discussed above for recommendations 1, 3, and 4 within 

30 days.

We appreciate the courtesies and cooperation of FAA and industry representatives 

during this audit. If you have any questions concerning this report, please contact 

me at (202) 366-1427 or Darren Murphy, Program Director, at (206) 220-6503.

#

cc: FAA Deputy Administrator

Chief Operating Officer, Air Traffic Organization

Assistant Administrator for Aviation Policy Planning

and Environment

Director, Audit and Evaluation

Anthony Williams, AAE-001

Martin Gertel, M-1
18

Exhibit A. Scope and Methodology

EXHIBIT A. SCOPE AND METHODOLOGY

We conducted this performance audit between June 2009 and August 2010 in 

accordance with generally accepted government auditing standards. Those 

standards require that we plan and perform the audit to obtain sufficient, 

appropriate evidence to provide a reasonable basis for our findings and 

conclusions based on our audit objectives. We believe that the evidence obtained 

provides a reasonable basis for our findings and conclusions based on our audit 

objectives.

To determine the principal causes of flight delays in the New York region, we 

analyzed data from FAA’s Aviation System Performance Metrics (ASPM)31

database, Flight Schedule Data System (FSDS),32 and Operations Network 

(OPSNET)33 as well as from the Department’s Bureau of Transportation Statistics 

(BTS).34

To identify the corresponding effect of New York delays, we reviewed reports, 

studies, and research papers from American Airlines, MITRE Corporation, 

EUROCONTROL, George Mason University, University of Maryland, and 

Massachusetts Institute of Technology. We also analyzed the information 

included in FAA’s Delay Propagation database that is currently under 

development to determine if any data deficiencies existed. Finally, we 

interviewed officials from MITRE Corporation, EUROCONTROL, National Air 

Traffic Services for the United Kingdom, BTS, and FAA’s Office of Policy and 

Plans and Air Traffic Organization.

Based on our prior assessments and interviews with agency officials, we

have concluded that these databases are reliable for the purposes of this audit. In 

addition, we reviewed the notices and orders that led to the establishment of flight 

caps at Newark Liberty and John F. Kennedy International Airports and extended 

the existing flight caps at LaGuardia. We interviewed officials from FAA’s Air 

Traffic Control Command Center, Office of Performance Analysis and Strategy,

and Office of Aviation Policy and Plans. We also interviewed officials from the 

Port Authority of New York and New Jersey as well as JetBlue Airways and 

Continental Airlines.

31 ASPM is an FAA database of air traffic control performance measures that includes flight delays, cancellations, 

scheduled flights, operations, taxi times, and causes for delays. 32 FSDS is an FAA database of published air carrier flight schedules. 33 OPSNET is an FAA database of air traffic control movement operations for all towers, centers, and approach control 

facilities. 34 BTS data include information about air carrier on-time performance, flight delays, and cancellations. They are based 

on data filed each month by the 19 reporting air carriers with the BTS Office of Airline Information as described in 

14 CFR Part 234 of DOT’s regulations.
19

Exhibit B. OIG Reports and Testimonies Addressing New York Flight Delays

EXHIBIT B. OIG REPORTS AND TESTIMONIES ADDRESSING 

NEW YORK FLIGHT DELAYS

Air Carrier Flight Delays and Cancellations, Report Number CR-2000-112, 

July 25, 2000.

Airline Industry MetricsTrends on Demand and Capacity, Aviation System 

Performance, Airline Finances, and Service to Small Airports, Correspondence 

Number CC-2004-006, January 8, 2004.

Short- and Long-Term Efforts To Mitigate Flight Delays and Congestion,

Report Number CR-2004-066, June 17, 2004.

Airspace Redesign Efforts Are Critical To Enhance Capacity but Need Major 

Improvements, Report Number AV-2005-059, May 13, 2005.

Aviation Industry PerformanceTrends in Demand and Capacity, Aviation 

System Performance, Airline Finances, and Service to Small Airports,

Correspondence Number CC-2005-057, June 30, 2005.

Aviation Industry PerformanceA Review of Summer 2007 Aviation System 

Performance, Correspondence Number CC-2008-039, December 27, 2007.

Status Report on Actions Underway To Address Flight Delays and Improve 

Airline Customer Service, Testimony Number CC-2008-058, April 9, 2008.

Observations on Short-Term Capacity Initiatives, Report Number AV-2008-

087, September 26, 2008.

Aviation Industry PerformanceA Review of the Aviation Industry in 2008,

Correspondence Number CC-2009-039, May 6, 2009.

Progress and Remaining Challenges in Reducing Flight Delays and Improving 

Airline Customer Service, Testimony Number CC-2009-067, May 20, 2009.

Status of the Aviation Rulemaking Committee’s 77 Initiatives for Reducing 

Delays in the New York Area, Report Number AV-2010-003, October 21, 

2009.

OIG reports and testimonies are available on our website: www.oig.dot.gov
20

Exhibit C. Major Contributors to This Report

EXHIBIT C. MAJOR CONTRIBUTORS TO THIS REPORT

Darren Murphy Program Director

Name Title

Jerrold Savage Project Manager

Stephen Smith Senior Transportation Industry Analyst

Mike Dunn Auditor

Andrew Sourlis Analyst

Teri Vogliardo Analyst

Sandy DeLost Information Technology Specialist

Andrea Nossaman Writer-Editor
21

Appendix. Agency Comments

APPENDIX. AGENCY COMMENTS

Federal Aviation

Administration

Memorandum

Date: September 29, 2010 

To: Matthew E. Hampton, Deputy Assistant Inspector General for Aviation and 

Special Program Audits 

From: Clay Foushee, Director, Audit and Evaluation

Prepared by: Anthony Williams, x79000 

Subject: OIG Draft Report: New York Flight Delays Have Three Main Causes, But 

More Work Is Needed To Understand Their Nationwide Effect

Both the Department of Transportation (DOT) and Federal Aviation Administration (FAA) 

continue to work hard to alleviate aviation congestion and delays. Since Fiscal Year (FY) 2000, 

22 airfield projects have opened at 19 of the 35 Operational Evolution Plan (OEP) airports.

These include 16 new runways, 3 taxiways, 1 runway extension, 1 airfield reconfiguration 

completed, and 1 airfield reconfiguration two-thirds completed. These projects enable the 

potential to accommodate more than 2 million annual operations and decrease average delay per 

operation at these airports by about 5 minutes. Eight other projects (3 airfield reconfigurations, 

2 runway extensions, 3 new runways) are in the planning or environmental stage at OEP airports 

through 2018.

The Next Generation Air Transportation System (NextGen) also is also intended in part, to help 

communities make better use of their airports by making air travel more predictable, reducing 

delays and greater flexibility to get around weather problems. The implementation of NextGen 

technologies is complex and requires investments by both FAA and the industry, who will need 

to install NextGen avionics in cockpits. By 2018, many NextGen technologies are planned to be 

operational in various regions of the country and users will begin realizing the benefits of those 

upgrades.

The economic downturn has resulted in lower passenger demand with a corresponding decline in 

overall operations and delays. However, in certain congested areas such as New York, travelers 

may still experience delays. FAA is working aggressively to implement operational and structural 

improvements so we are prepared to handle the inevitable uptick in traffic in the future. 

For example, FAA is continuing work in the New York area to implement precision procedures 

such as area navigation and required navigation performance (otherwise known as RNAV/RNP),
22

Appendix. Agency Comments

airspace redesign and the creation of optimal descent procedures - all of which will result in more 

efficient operations and yield environmental benefits. FAA is also continuing to implement 

airspace redesign, which will improve the efficiency and reliability of the air traffic operations in 

the New York, New Jersey and Philadelphia region. The next phase is expected to come on-line 

late next spring and will focus on New York West departures.

FAA also maintains schedule limits on operations at LaGuardia (LGA), John F. Kennedy (JFK)

and Newark airports, and currently has a work group that is reevaluating the current scheduling

orders to ensure they effectively limit delays, while also allowing for maximum passenger

throughput. FAA has also worked with the air carriers and the Port Authority of New York and

New Jersey (Port Authority) to ensure that operations at JFK run as smooth as possible while the

airfield and Bay runway are under construction. Specifically, FAA reached agreements with the

carriers serving JFK to maintain their winter schedules throughout the four-month runway

closure (March-June 2010), which has helped tremendously with the operation of the airport

during this construction period.

Recommendations and Responses

OIG Recommendation 1: Reexamine flight caps at Kennedy, LaGuardia, and Newark airports,

basing the caps on more realistic airport operating conditions, air carrier scheduling practices,

and a goal towards reducing delays to an acceptable rate and length of delay, FAA should

incorporate the views of air carriers, the airport operator, and passenger groups as well as lessons

learned from other slot-controlled airports.

FAA Response: Partially Concur. Kennedy, LaGuardia and Newark airports are currently

operating under short-term orders, which expire in October 2011. As part of our ongoing efforts

to address congestion at these airports, FAA currently has an internal workgroup that is

evaluating the orders at the three New York airports and any proposed changes would be subject

to notice and comment. In particular, the workgroup is evaluating model results, current

scheduling practices and re-evaluating policy goals related to acceptable level of delay. We

anticipate that any potentially recommended changes to the existing schedule limits would be

published for notice and comment by December 2011. The reason for partial concurrence is

because FAA already completed many of the Office of Inspector General's recommendations

when it established the target operational limits for Kennedy and Newark in 2007/2008.

Specifically, the recommendation does not recognize that FAA did use actual airport operating

conditions and worked with MITRE Corporation to model capacity at these airports using every

hour, of every weekday, over many months at the two airports. FAA modeled the impact of

various airline schedules and airport scheduling limits, incorporating variations to the airport

capacity due to weather, runway configurations and other operational factors.

In arriving at these flight limits, FAA incorporated the views of air carriers and the airport

operator. Notice and comment periods have also been provided on the FAA scheduling orders for 

the three airports. Establishing scheduling targets requires careful consideration of benefits, costs 

and tradeoffs. As our stakeholders frequently point out higher limits provide more opportunities 

for market access but result in more delay and lower on-time performance. Low scheduling 

targets will improve performance and reduce delays but results in unused capacity and limits 

access to the airport.
23

Appendix. Agency Comments

OIG Recommendation 2: Establish a working group of air carriers, academia, and other

aviation research organizations to enhance the understanding of delay propagation (e.g., develop

viable analytic methodologies, useful database structures, and common terms of reference).

FAA Response: Concur. FAA will continue to work with air carriers, academia, and other

aviation research organizations to increase the usefulness of its existing delay propagation

models. Given the complexities associated with modeling delay propagation, FAA recognizes

that this research is a multi-year effort which will require on-going interaction with industry,

academia, and other stakeholders so as to continually improve modeling capabilities in this area.

FAA is exploring different avenues to engage stakeholders on this issue. Within one year of this

recommendation, FAA will either host or participate in a forum which will focus on enhancing

its delay propagation modeling capabilities.

OIG Recommendation 3: Enhance existing flight delay data by obtaining aircraft tail numbers

for domestic and international flight operations of U.S. air carriers in order to better study and

manage the propagation effect of flight delays.

FAA Response: Partially Concur. From an analytical standpoint, FAA agrees it would be

desirable to expand our delay propagation modeling capability, which currently focuses on

domestic operations by tail number, to include international flight operations of U.S. air carriers.

FAA will work with Bureau of Transportation Statistics (BTS) to determine the feasibility of

obtaining the pertinent international flight information for U.S. air carries and whether

rulemaking would be required. FAA, working with BTS, will make this determination within one 

year of this recommendation. If data becomes available, FAA will seek funding to incorporate 

this information into its delay propagation models. Within one year of receiving necessary 

funding, we will have incorporated the international flight data into the delay propagation models 

and will have determined the impact on the published delay propagation multipliers.

OIG Recommendation 4: Complete development of a viable methodology for measuring the

dynamics of flight delays at New York (as well as other U.S. airports) and their propagation

nationwide. This methodology should include the ability to measure both the amount of delay

time being propagated and the number of subsequent flights being impacted.

FAA Response: Partially Concur. FAA has developed a state of the art methodology to measure 

delay propagation on an airport, regional, and nationwide basis. As previously discussed, the 

science of modeling this complex phenomenon continues to evolve and FAA continues it work in 

this area. The report, and these recommendations could better recognize the efforts FAA has 

pursued in this regard, and the progress achieved. As written it lends the reader to believe that 

FAA has not progressed in this area. FAA considers flight delay propagation modeling an 

evolving science, and will pursue improvements continuously.
Flight Delays in the New York Region and Corresponding Effects Nationwide

Section 508 Compliant Presentation

The following pages contains a textual version of Figure 4 of found in this document. 

These pages were not in the original document but have been added here to 

accommodate assistive technology.

Figure 4. Comparison of Flight Schedules with Various Capacity Measures at 

Kennedy (June 18, 2008)

Time Period Capacity Under 

Instrument 

Flight 

Conditions

Capacity 

Under Visual 

Flight 

Conditions

FAA Target 

For Caps

FAA Level 

of

Approved 

Operations

6:00am 16.75 21.75 20 19

6:15am 16.75 21.75 20 5

6:30am 16.75 21.75 20 16

6:45am 16.75 21.75 20 15

7:00am 16.75 21.75 20 24

7:15am 16.75 21.75 20 18

7:30am 16.75 21.75 20 17

7:45am 16.75 21.75 20 26

8:00am 16.75 21.75 20 22

8:15am 16.75 21.75 20 22

8:30am 16.75 21.75 20 22

8:45am 16.75 21.75 20 13

9:00am 16.75 21.75 20 39

9:15am 16.75 21.75 20 13

9:30am 16.75 21.75 20 20

9:45am 16.75 21.75 20 17

10:00am 16.75 21.75 20 12

10:15am 16.75 21.75 20 8

10:30am 16.75 21.75 20 10

10:45am 16.75 21.75 20 13

11:00am 16.75 21.75 20 15

11:15am 16.75 21.75 20 14

11:30am 16.75 21.75 20 12

11:45am 16.75 21.75 20 16

12:00pm 16.75 21.75 20 18

12:15am 16.75 21.75 20 10

12:30am 16.75 21.75 20 14

12:45am 16.75 21.75 20 26
1:00pm 16.75 21.75 20 13

1:15pm 16.75 21.75 20 16

1:30pm 16.75 21.75 20 17

1:45pm 16.75 21.75 20 29

2:00pm 16.75 21.75 20 11

2:15pm 16.75 21.75 20 15

2:30pm 16.75 21.75 20 14

2:45pm 16.75 21.75 20 42

3:00pm 16.75 21.75 20 8

3:15pm 16.75 21.75 20 21

3:30pm 16.75 21.75 20 16

3:45pm 16.75 21.75 20 33

4:00pm 16.75 21.75 20 18

4:15pm 16.75 21.75 20 22

4:30pm 16.75 21.75 20 21

4:45pm 16.75 21.75 20 20

5:00pm 16.75 21.75 20 21

5:15pm 16.75 21.75 20 19

5:30pm 16.75 21.75 20 21

5:45pm 16.75 21.75 20 24

6:00pm 16.75 21.75 20 22

6:15pm 16.75 21.75 20 12

6:30pm 16.75 21.75 20 21

6:45pm 16.75 21.75 20 26

7:00pm 16.75 21.75 20 34

7:15pm 16.75 21.75 20 15

7:30pm 16.75 21.75 20 23

7:45pm 16.75 21.75 20 16

8:00pm 16.75 21.75 20 28

8:15pm 16.75 21.75 20 8

8:30pm 16.75 21.75 20 21

8:45pm 16.75 21.75 20 25

9:00pm 16.75 21.75 20 31

9:15pm 16.75 21.75 20 21

9:30pm 16.75 21.75 20 21

9:45pm 16.75 21.75 20 16

10:00pm 16.75 21.75 20 36

10:15pm 16.75 21.75 20 18

10:30pm 16.75 21.75 20 17

10:45pm 16.75 21.75 20 15

Source: OIG Analysis of FAA Data