AIR TRAFFIC CONTROL: 

POTENTIAL FATIGUE FACTORS 

Federal Aviation Administration 

Report Number: AV-2009-065 

Date Issued: June 29, 2009 
U.S. Department of 

Memorandum

Transportation 

Office of the Secretary 

of Transportation 

Office of Inspector General 

Subject: ACTION: Report on Air Traffic Control: 

Potential Fatigue Factors 

Federal Aviation Administration 

Date: June 29, 2009 

Report Number AV-2009-065 

From: Ann Calvaresi-Barr 

Principal Assistant Inspector General 

 for Auditing and Evaluation 

Reply to 

Attn. of: JA-1 

To: Federal Aviation Administrator 

This report presents the results of our audit of fatigue factors that could impact air 

traffic controllers. We conducted this review at three Chicago area air traffic 

control facilities: Chicago O’Hare International Airport Air Traffic Control Tower 

(Chicago O’Hare), Chicago Terminal Radar Approach Control Facility (Chicago 

TRACON), and Chicago Air Route Traffic Control Center (Chicago ARTCC). 

These 3 facilities are among the top 10 busiest air traffic control facilities in the 

United States. Nationwide, during 2007, Chicago O’Hare was the second busiest 

air traffic control tower with 927,000 airport operations, Chicago ARTCC the 

fourth busiest air route traffic control center with 2.8 million operations, and 

Chicago TRACON the sixth busiest TRACON with 1.4 million operations. 

We conducted this audit at the request of Senator Richard Durbin of Illinois. 

Senator Durbin expressed specific concerns that staffing shortfalls, longer hours 

on the job, and a growing shortage of certified controllers may be causing 

controller fatigue at these critical facilities. He asked that we review factors that 

could potentially cause controller fatigue at these locations. 

Consistent with Senator Durbin’s request, our audit objectives were to (1) identify 

and evaluate key factors that could cause controller fatigue at Chicago O’Hare, 

Chicago TRACON, and Chicago ARTCC and (2) identify what measures FAA 

has taken to mitigate potential controller fatigue at these locations. 

We conducted our audit between January 2008 and February 2009 in compliance 

with generally accepted government auditing standards. Exhibit A details our 

audit scope and methodology. Exhibit B lists locations visited or contacted. 
2

BACKGROUND 

Fatigue is defined as a mental weariness resulting from exertion. Fatigue can be 

mental or physical and can manifest as either somnolence (decreased wakefulness) 

or as a general decrease in attention. Fatigue can cause problems for individuals 

who perform tasks that require constant concentration, such as air traffic control. 

Additionally, the nature of air traffic control requires shift work, which can 

exacerbate fatigue because it often requires individuals to work at times when they 

would normally be sleeping or sleep at times when they would normally be awake. 

Since the 1980s, the National Transportation Safety Board (NTSB) has been 

concerned about the effects of fatigue on individuals performing critical functions 

in all transportation industries, including air traffic control. The NTSB has made 

numerous fatigue-related safety recommendations addressing topics such as rest 

periods between shifts, scheduling practices, and fatigue awareness training for 

personnel working in the transportation industry. As part of its investigation into 

the August 2006 crash of Comair Flight 5191, the NTSB expressed concerns in 

April 2007 about the impact of fatigue on controllers working rotational shifts. In 

its investigative report, the NTSB noted that the lone controller on duty at the time 

of the accident had only 2 hours of sleep prior to his shift. Based on its Comair 

investigation, the NTSB made specific recommendations to FAA regarding fatigue 

for personnel performing air traffic control. 

RESULTS IN BRIEF 

We identified a number of factors at Chicago O’Hare, Chicago TRACON, and 

Chicago ARTCC that could create potential fatigue conditions for controllers. 

These factors include minimal hours between shifts and counter rotational shifts 

with progressively earlier start times; scheduled overtime; and on-the-job training 

(OJT), which requires a high level of concentration and focus. We conducted a 

series of statistical analyses using schedule information and time and attendance 

data and found that these factors are occurring at all three Chicago air traffic 

control facilities in varying degrees. For example, we found that most controllers 

at the three locations were scheduled to work at least one shift each week in which 

their rest period between shifts was less than 10 hours. 

We also found that overtime hours at Chicago O’Hare and Chicago TRACON had 

increased significantly between fiscal year (FY) 2006 and FY 2007 (by 75 percent 

and 67 percent, respectively). However, the potential impact on fatigue was 

negligible because controllers did not always work all days of a scheduled 6-day 

(i.e., overtime) work week. For instance, at Chicago O’Hare, 18 of the 

66 controllers in our sample were scheduled to work a 6-day work week during the 

52-week period we reviewed, but only 8 controllers (less than 50 percent) actually 

worked all 6 days. This was because when scheduled for a 6-day work week, 
3

controllers often took leave for shifts other than their scheduled overtime shift, 

thus working less than 6 days while still earning overtime pay. 

Additionally, we found that certified controllers at all three facilities conducted 

OJT on a regular basis. The time spent conducting OJT in our samples ranged 

from 1 to 5 days per week, and officials at all three facilities cautioned that OJT is 

expected to increase significantly over the next several years as more trainees are 

added to the workforce. 

While all three facilities have high traffic volumes and complex airspace, their 

staffing levels exceeded established staffing ranges for those locations. Those 

ranges do not, however, consider the ratio of trainees to certified controllers. The 

ratio of trainees to certified controllers at Chicago TRACON and Chicago O’Hare 

exceed FAA’s national average of 27 percent (30 percent at Chicago TRACON 

and 40 percent at Chicago O’Hare).1

 In addition, we found that none of the three 

locations has established procedures for rotating controllers through more complex 

positions during scheduled shifts, even though the complexity of various facility 

positions can vary extensively. 

Fatigue can have serious safety implications and has been identified by the NTSB 

as a potential contributing factor in several operational errors (where controllers 

fail to maintain required distances between aircraft). Yet, FAA does not 

consistently address human factors issues, such as fatigue and situational 

awareness, during either the preliminary or final operational error investigation 

process. For example, at Chicago ARTCC, final operational error reports 

indicated that a controller’s work schedule was a “rotation,” but there was no 

further information provided to determine the days or the shifts the controller 

actually worked. 

FAA is taking several actions at the national level to address NTSB 

recommendations regarding fatigue. These actions include amending FAA Order 

7210.3 to (1) increase the time available for rest (between shifts) from 8 hours to 

10 hours, (2) increase the time available for rest after working a midnight shift on 

the fifth day of the week from 12 hours to 16 hours for facilities that utilize a 6-

day work week, and (3) allow controllers to sleep or rest when not controlling 

traffic. FAA has also developed a 40-minute, computer-based instruction 

refresher training module on the effects of fatigue on controller performance. At 

the time of our review, however, none of these actions had been implemented at 

the three facilities. 

Our report makes a number of recommendations to FAA on actions it needs to 

take to mitigate potential fatigue factors. 

 

1

 As of December 2008. 
4

FINDINGS 

Controllers at All Three Facilities Were Scheduled To Work Shifts 

with Rest Periods of Less Than 10 Hours Between Each Shift 

Based on our sample analysis, controllers at the three Chicago air traffic control 

facilities were scheduled to work at least one “quickturn”2

 between 66 and 

86 percent of the time during the week. That is, controllers were scheduled to 

work at least one shift each week where the rest period between that shift and the 

next shift was less than 10 hours.3

 At the three Chicago air traffic control 

facilities, controllers worked a type of schedule commonly referred to as a “2-2-1 

rotation.” While the configuration of the 2-2-1 may vary, this particular 

scheduling practice usually consists of a work week with two consecutive evening 

shifts, followed by two consecutive day shifts, followed by one midnight shift, as 

shown in table 1. 

Table 1. Example of a 2-2-1 Schedule 

Day Shift Start Time End Time 

1 Evening 4:00 p.m. Midnight 

2 Evening 2:00 p.m. 10:00 p.m.* 

3 Day 7:00 a.m. 3:00 p.m. 

4 Day 6:00 a.m. 2:00 p.m.* 

5 Midnight 10:00 p.m. 6:00 a.m. 

*Rest periods between shifts close to the 8-hour minimum required by 

FAA regulations.

As shown in table 2 below, we found that both Chicago O’Hare and Chicago 

ARTCC scheduled most controllers to have at least one quickturn during the 

week. We also found that controllers “traded into” quickturns by switching their 

assigned shift for another shift. Although controllers were scheduled to work 

quickturns or “traded into” quickturns, they did not always work those shifts 

because they either took leave or switched back to their originally scheduled shift. 

 

2

 A “quickturn” is a schedule characterized by shifts with minimal rest periods between them. 

3

 FAA Order 7210.3 requires at least 8 hours between shifts for rest. For the purpose of our review, we considered a 

quickturn to be less than 10 hours between shifts because FAA is in the process of amending FAA Order 7210.3 to 

increase the time available for rest from 8 hours to 10 hours. 
5

Table 2. Occurrence of Quickturns 

Facility Sample Size Scheduled at Least 

One Quickturn 

Quickturns Not 

Worked 

Chicago O’Hare 66 57 (86%) 44% 

Chicago TRACON 67 not applicable* not applicable* 

Chicago ARTCC 68 45 (66%) 27% 

*Managers at the Chicago TRACON indicated that they too scheduled controllers to work the 2-2-1 

schedule. However, we could not verify this information because the TRACON was unable to provide 

schedule data for all the weeks in our sample. 

This type of work schedule offers minimal opportunity for sleep when the time 

required for commuting, eating, and other necessary daily activities is taken into 

account. The NTSB has expressed concern regarding this type of work schedule 

because it limits the amount of time for rest between shifts. However, it is 

ultimately the responsibility of each controller to ensure that he or she gets a 

sufficient amount of rest between shifts. Controllers we spoke with told us they 

generally like this schedule because it only requires them to work one midnight 

shift per week and allows more consecutive time off during the week (i.e., the 

equivalent of a 3-day weekend). 

Controllers at All Three Facilities Worked Schedules That Required 

Overtime 

All three Chicago air traffic control facilities needed and used overtime to meet 

their operational needs. Scheduled overtime occurs when controllers are 

scheduled, in advance, to work 6 days instead of 5 days during 1 week. However, 

the methods for assigning overtime varied from facility to facility. For example, 

Chicago TRACON and Chicago O’Hare used scheduled overtime (i.e., scheduled 

6-day work weeks) to meet operational needs. In contrast, Chicago ARTCC 

primarily used call-up overtime (i.e., controllers are called in to work on a 

scheduled day off as needed). 

Our results indicate that even though overtime hours have increased significantly 

at two of the three facilities,4

 the potential impact on fatigue was negligible 

because controllers did not always work all days of a scheduled, 6-day work week 

(see table 3 below). For instance, at Chicago O’Hare, 18 of the 66 controllers in 

our sample were scheduled to work a 6-day work week during the 52-week period 

we reviewed, but only 8 controllers (less than 50 percent) actually worked all 

 

4

 Overtime hours at Chicago O’Hare increased by 75 percent from FY 2006 to FY 2007, while overtime hours at 

Chicago TRACON increased by 67 percent. 
6

6 days. This was because when scheduled for a 6-day work week, controllers 

often took leave for shifts other than their scheduled overtime shift, thus working 

less than 6 days but still earning overtime pay. Nonetheless, when controllers 

actually work 6 days, the potential for fatigue can increase. 

Table 3. Occurrence of Overtime at Chicago Area 

Air Traffic Control Facilities 

Facility Sample Size Scheduled To 

Work a 6-day 

Week 

Worked All 

6 Days 

Chicago O’Hare 66 18 (27%) 8 of 18 (44%) 

Chicago TRACON 67 16 (24%) 12 of 16 (75%) 

Chicago ARTCC 68 0 (0%) not applicable 

Controllers at All Three Facilities Conducted On-the-Job Training 

We found that Certified Professional Controllers (CPCs) at all three facilities 

conducted OJT on a consistent basis. Facility training for new hires consists of 

several phases, the last of which is OJT. During OJT, a CPC oversees and 

instructs a trainee as they work a control position handling real-time air traffic. 

Officials at all three facilities agreed that conducting OJT can be fatiguing for the 

OJT instructor because it requires a high level of concentration and attention to 

monitor a trainee’s actions and quickly correct potential errors, as the instructor is 

ultimately responsible for maintaining minimum separation between aircraft. 

As shown in table 4 on the next page, the time CPCs spent conducting OJT in our 

samples ranged from 1 to 5 days per week during the 52-week period we 

reviewed. Specifically, 

 at Chicago O’Hare, controllers in our sample conducted OJT at least 1 day 

during the week as much as 58 percent of the time. 

 at Chicago TRACON, controllers in our sample conducted OJT at least 1 day 

during the week as much as 39 percent of the time. 

 at Chicago ARTCC, controllers in our sample conducted OJT at least 1 day 

during the week as much as 43 percent of the time. 
7

Table 4. Occurrence of OJT 

Facility Sample Size OJT Conducted 

During at Least 

One Shift 

Average OJT 

Conducted During 

the Work Week 

Chicago O’Hare 66 38 (58%) 

1 hour and 

42 minutes 

Chicago TRACON 67 26 (39%) 2 hours and 1 minute

Chicago ARTCC 68 29 (43%) 

2 hours and 

57 minutes 

While the way FAA trains controllers has not significantly changed over the years, 

FAA expects to hire and train approximately 15,000 new controllers through 2018. 

As FAA hires more new controllers to compensate for the ongoing surge in 

attrition, the need for more OJT will increase and the potential for CPCs to 

experience fatigue from conducting OJT may increase as well. The number of 

controllers in training, the number of OJT instructors, and the time spent 

conducting OJT by location will all be significant watch items for FAA as it 

implements plans to hire and train the next generation of air traffic controllers. 

Other Factors Can Also Create Fatigue Conditions for Controllers 

Facility personnel also identified several other factors that could cause fatigue. 

These include inadequate staffing levels, increased work load (i.e., traffic volume 

and complexity), and extended time on position or lack of position rotation. 

However, these factors could not be easily measured or statistically validated. 

Therefore, we relied on evidence obtained from discussions with facility personnel 

and macro-level data provided by FAA to determine the extent to which these 

factors were occurring and to gauge the impact they could potentially have on 

controller fatigue. 

Staffing Levels 

As shown in table 5 below, as of December 2008, overall staffing levels at each of 

the three facilities exceeded established staffing ranges. Specifically, Chicago 

O’Hare had 5 more controllers than the authorized staffing range, Chicago 

TRACON had 3 more controllers, and Chicago ARTCC had 51 more controllers. 

Those ranges do not, however, consider the ratio of trainees to certified 

controllers. 

Controllers in training now represent nearly 27 percent of the workforce 

nationwide (up from 15 percent in 2004). However, that percentage can vary 
8

extensively by location—from as little as 0 percent (e.g., Pittsburgh air traffic 

control tower) to as much as 45 percent (e.g., Orlando International air traffic 

control tower). The ratio of trainees to total controller staff for all three Chicago 

air traffic control facilities ranged from 20 percent to 40 percent. In our view, 

including this information in reported staffing levels for FAA’s facilities is 

important as it could have a direct bearing on CPC fatigue and on-the-job training. 

Table 5. December 2008 Staffing Levels 

Facility Authorized 

Staffing 

Range 

Total on 

Board 

(CPCs + 

Trainees)

CPCs Trainees Percent in 

(Training/Total 

on Board) 

Number of 

Facilities with 

Higher Percent 

in Training 

Chicago 

O’Hare 56-68 73 44 29 40% 46 out of 314 (15%) 

Chicago 

TRACON 82-100 103 72 31 30% 126 out of 314 (40%) 

Chicago 

ARTCC 312-382 433 348 85 20% 224 out of 314 (71%) 

FAA is now verifying (through a hired contractor) whether facility staffing ranges 

accurately reflect facility needs. FAA’s contractor has completed this process at 

Chicago O’Hare and Chicago ARTCC; however at the time of our review, the 

staffing ranges at Chicago TRACON had not been validated for accuracy. 

Traffic Volume and Complexity 

Facility personnel at all three locations told us that Chicago’s adverse weather 

conditions such as heavy snowfalls increase the complexity of its high-volume 

traffic, which could contribute to controller fatigue. Additionally, ongoing 

changes due to the O’Hare Modernization Project (OMP)5

—such as added 

operational positions due to a new runway configuration and increased capacity—

may increase operational intensity. 

In anticipation of the added operational requirements due to the OMP, 

Chicago O’Hare has requested an additional 10 controllers. Once the OMP is 

fully implemented, FAA should reevaluate the staffing standard to ensure that the 

new range is appropriate. 

 

5

 The OMP is a plan to increase the efficiency and capacity of the airport by adding a new runway, extending two 

existing runways, and relocating three other runways. 
9

Position Rotation 

Time on position is the average amount of time a controller spends controlling 

traffic out of an 8-hour shift. The contract between FAA and the National Air 

Traffic Controllers Association (NATCA) states that it is a mutual goal that 

controllers should only work an operational position for 2 hours at a time before 

they are relieved. During an 8-hour shift, controllers may work several different 

positions but for no more than 2-hour increments. During the balance of their 

shifts, controllers generally are either taking breaks, conducting non-operational 

duties, attending briefings, or receiving recurrent training. 

All three Chicago air traffic control facilities had an average time on position of 

approximately 4 to 4.5 hours per shift. While the length of time on position is 

important, not every control position can be equally compared. For example, 

controllers at Chicago O’Hare responsible for runway oversight often have to 

issue instructions to multiple aircraft, which requires a great deal of concentration 

and focus. In contrast, there are other air traffic control positions that are less 

complex, such as clearance delivery, which require no communication with 

moving aircraft. If controllers work demanding positions several times during an 

8-hour shift, the potential for fatigue increases. We found that none of the 

Chicago facilities had written guidance in place to suggest how often or when 

controllers should rotate through more difficult positions. 

FAA Does Not Consistently Include Human Factors Issues When 

Investigating Operational Errors 

Fatigue can have serious safety implications and has been identified by the NTSB 

as a potential contributing factor in several operational errors. Yet, FAA’s process 

for investigating operational errors does not require specific data regarding all the 

fatigue factors that we identified. An operational error occurs when an air traffic 

controller does not ensure that FAA separation standards are maintained between 

aircraft. FAA categorizes operational errors as categories A through D based on 

the severity level of the operational error, with category A and category B being 

the most severe forms of operational errors. 

When an operational error occurs, an immediate investigation is conducted 

consisting of two phases. 

 The first phase results in a preliminary operational error report. This fact 

finding investigation is conducted by the facility within 4 hours of the 

occurrence of the operational error. 

 The second phase results in a final operational error report. The 

comprehensive final investigation identifies causal factors and recommends 
10

corrective action. The facility has 30 days to complete the final phase of the 

investigation. 

We examined the extent to which the six fatigue factors we identified (work 

schedule, overtime, OJT, staffing, traffic volume and complexity, and time on 

position) were addressed following an operational error. To determine this, we 

reviewed both the preliminary and final investigatory reports of all 41 category A 

and category B operational errors that occurred at the three facilities during FY 

2007 and FY 2008 and interviewed quality assurance personnel from each of the 

facilities. We found that although the person investigating the operational error 

follows a checklist when conducting the investigation, that person is not limited to 

asking only the questions on the checklist. They may ask more detailed, probing 

questions to determine whether fatigue contributed to the operational error. There 

are, however, currently no required questions on human factors such as fatigue. 

Of the six fatigue factors we identified, only information on two—traffic volume 

and complexity and time on position—was required on both the preliminary and 

final investigatory reports. Table 6 shows which fatigue factors are required for 

review as part of the preliminary operational error report and the final operational 

error report. 

Table 6. Potential Fatigue Factors Requirements 

for Operational Error Reports 

Potential Fatigue Factor Preliminary Operational 

Error Report 

Final Operational 

Error Report 

Work Schedule Not Required Required 

Overtime Not Required Not Required 

On-the-Job Training Not Required Required 

Staffing Required Not Required 

Traffic Volume and 

Complexity 

Required Required 

Time on Position Required Required 

Because FAA does not require that the other factors be addressed on both reports, 

it does not accumulate data on human factors issues to determine if they contribute 

to operational errors, how often they occur, and if they present any systemic 

issues. FAA handles these remaining factors as follows: 

Staffing Information: FAA requires staffing information (such as the number of 

controllers on duty, on position, and on break) at the time of the operational error 

on the preliminary investigative report but not the final report. 

Work Schedule and OJT Information: Work schedule and OJT information is 

not required on the preliminary investigative report but is an element of the final 
11

report. However, the work schedule information provided by the facility for the 

final report often does not provide enough information to identify the schedule 

actually worked by the controller for the entire week. For example, at Chicago 

ARTCC, the final report indicated that the controller’s work schedule was a 

“rotation” and identified the amount of time worked in the controller’s previous 

and current shifts prior to the operational error; however, there was no information 

to determine the days or the shifts the controller worked during the entire week. 

An example of an operational error investigative report is shown in the figure 

below. 

Figure. Example of a Final Operational Error Report 

Although the final operational error report indicates whether OJT was in progress 

at the time of the operational error, it does not provide information on the length of 

time OJT was conducted during the shift. Our analysis found that 17 percent of 

the 41 operational errors occurred while the controller was conducting OJT. 

Overtime Information: We found that overtime information was not 

documented on either the preliminary or the final operational error investigative 

report. In our opinion, if the controller worked overtime the previous day or 

worked more than 40 hours during the prior work week, this information should be 

identified in the final operational error report. 

Although we found that the preliminary and final operational error reports did not 

always document the six fatigue factors we identified, we did find that some 

facilities tried to capture information on human factors during the investigation of 

operational errors. For example, Chicago O’Hare has developed and incorporated 

questions regarding human factors such as fatigue, work schedule, and overtime 

into the post-operational-error interview process. However, these efforts will 

remain inconsistent across facilities without FAA system-wide requirements. 
12

FAA Has Convened National Workgroups To Address Fatigue Factors 

but Has Not Implemented Changes 

The NTSB has made numerous fatigue-related safety recommendations addressing 

topics such as rest periods between shifts, scheduling practices, and fatigue 

awareness training. In terms of controller shift work and rest requirements, the 

NTSB specifically recommended in April 2007 that FAA take the following 

actions: 

 “Work with the National Air Traffic Controllers Association to reduce the 

potential for controller fatigue by revising controller work-scheduling policies 

and practices to provide rest periods that are long enough for controllers to 

obtain sufficient restorative sleep and by modifying shift rotations to minimize 

disrupted sleep patterns, accumulation of sleep debt, and decreased cognitive 

performance.” 

 “Develop a fatigue awareness and countermeasures training program for 

controllers and for personnel who are involved in the scheduling of controllers 

for operational duty that will address the incidence of fatigue in the controller 

workforce, causes of fatigue, effects of fatigue on controller performance and 

safety, and the importance of using personal strategies to minimize fatigue. 

This training should be provided in a format that promotes retention, and 

recurrent training should be provided at regular intervals.” 

While FAA took actions at the national level by forming a work group in 2007 to 

address these recommendations, most of these initiatives have not yet been 

implemented and therefore have not filtered down to the facility level. The work 

group recommended that FAA Order 7210.3 be amended to (1) increase the time 

available for rest (between shifts) from 8 hours to 10 hours, (2) increase the time 

available for rest after working a midnight shift on the fifth day of the week from 

12 hours to 16 hours for facilities that utilize a 6-day work week, and (3) allow 

controllers to rest when not controlling traffic during their shift. FAA Labor 

Relations plans to send a letter to NATCA to inform it of the proposed changes to 

FAA Order 7210.3 and provide an opportunity for NATCA to comment on the 

proposed changes or request negotiations. 

Although FAA has not finalized changes to its scheduling practices, it has made 

progress with fatigue training and awareness. Specifically, FAA (1) added a 1-

hour lesson on the effects of fatigue to the air traffic initial qualifications training 

courses at the FAA Academy; (2) developed a 40-minute, computer-based 

instruction refresher training module on the effects of fatigue on controller 

performance (scheduled to be implemented later this year); (3) developed and 

distributed a brochure for controllers to help them better understand the effect of 

shift work on fatigue; and (4) held a fatigue symposium in June 2008. 
13

CONCLUSION 

A number of factors exist at Chicago O’Hare, Chicago TRACON, and Chicago 

ARTCC that could cause controller fatigue. While our review focused on only the 

three Chicago facilities, it is likely that the fatigue factors that we identified exist 

at other large air traffic control facilities throughout the Nation. Our 

recommendations focus on actions FAA needs to take at the national level to 

mitigate potential fatigue factors and enhance the level of safety of the National 

Airspace System. 

RECOMMENDATIONS 

We recommend that FAA: 

1. Reevaluate the staffing ranges for Chicago O’Hare once the OMP is fully 

implemented to ensure that the range is appropriate and meets the new 

operational needs of the facility. 

2. Approve the recommended changes to FAA Order 7210.3 and implement 

these changes at all air traffic control facilities. These changes include 

(a) increasing the minimum rest period between shifts from 8 to 10 hours, 

(b) increasing the time available for rest after working a midnight shift on the 

fifth day of a 6-day work week from 12 to 16 hours, and (c) allowing 

controllers to rest during their shift when not controlling traffic. 

3. Provide mandatory refresher training to controllers annually to reinforce 

fatigue awareness and mitigation strategies. This training should include a 

comprehensive, multi-faceted approach to minimizing employee fatigue. 

4. Expand operational error investigatory requirements to include more detailed 

information on fatigue factors, such as overtime, OJT, and work schedule 

that could create fatigue conditions to determine whether these factors are a 

contributory cause to operational errors, the frequency in which the factors 

are occurring, and whether or not the existence of the factors indicate a 

systemic problem. The reports should at a minimum include (a) whether the 

controller worked overtime during the previous day or worked more than 

40 hours during the prior work week; (b) the length of time the controller 

conducted OJT, if applicable; and (c) the exact days and shifts worked by the 

controller during the week the operational error occurred. 

5. Require all facilities to establish procedures to rotate controllers through 

challenging and less demanding positions during each shift to mitigate the 

potential for fatigue to occur. 
14

AGENCY COMMENTS AND OFFICE OF INSPECTOR GENERAL 

RESPONSE 

We provided FAA with our draft report on May 26, 2009, and received its 

response on June 24, 2009. FAA concurred with recommendations 1 through 4 

and provided appropriate planned actions and target completion dates. FAA 

partially concurred with recommendation 5, stating that procedures for directing 

controller work assignments have been developed at the national level and are 

included in FAA directives such as FAA Orders 7210.3 and 1320.1. FAA also 

stated that additional guidance on providing relief breaks is contained in Article 33 

of the Agency’s contract with NATCA. FAA’s response is included in its entirety 

in the appendix to this report. 

We request that FAA clarify its response to recommendation 5 as we were unable 

to determine whether FAA Orders 7210.3 and 1320.1 specifically address 

controller rotation in relation to position complexity. Likewise, Article 33 of 

FAA’s contract with NATCA only addresses time on position before relief breaks 

are given, not rotational requirements due to position complexity. 

ACTIONS REQUIRED 

FAA’s planned actions and target dates for recommendations 1, 2, and 4 are 

responsive, and we consider these recommendations resolved pending completion. 

While FAA’s actions to address recommendation 3 are also responsive, we request 

that FAA provide us with its target issuance date for its pending Order on “Air 

Traffic Technical Training.” In accordance with DOT Order 8000.1C, we request 

that FAA clarify its response in writing regarding recommendation 5 within 

30 days of this report. 

We appreciate the courtesies and cooperation of FAA representatives during this 

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

(202) 366-1427 or Daniel Raville, Program Director, at (202) 366-1405. 

# 

cc: FAA Deputy Administrator 

FAA Chief of Staff 

Martin Gertel, M-100 

Anthony Williams, ABU-100 
15

EXHIBIT A. SCOPE AND METHODOLOGY 

We conducted this performance audit in accordance with generally accepted 

Government Auditing Standards prescribed by the Comptroller General of the 

United States. As required by those standards, we obtained evidence that we 

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

audit objectives. We used the following scope and methodology in conducting 

this review. 

We conducted this audit between January 2008 and February 2009. The audit 

included site visits to three major air traffic control facilities in the Chicago 

metropolitan area: Chicago O’Hare, Chicago TRACON and Chicago Air Route 

Traffic Control Center. We also conducted audit fieldwork at FAA Headquarters 

in Washington, DC; the FAA Training Academy in Oklahoma City, OK; and 

NATCA Headquarters in Washington, DC. 

To identify key factors that may contribute to controller fatigue we conducted site 

visits at all three Chicago air traffic control facilities and conducted numerous 

interviews with facility management; administrative personnel responsible for 

quality assurance, training, and scheduling; and NATCA representatives. 

To determine the extent to which the factors were occurring, the OIG statistician 

selected a simple random statistical sample of controllers and their work weeks for 

each of the three facilities. The universe consisted of 52 work weeks for each 

controller for a 1-year scheduling period beginning August 5, 2007, and ending 

August 2, 2008. Chicago O’Hare had 45 controllers and therefore a schedule with 

2,340 controller work weeks (45 controllers x 52 weeks) from which a sample of 

66 was selected. Chicago TRACON had 69 controllers and therefore a schedule 

with 3,588 controller work weeks (69 controllers x 52 weeks) from which a 

sample of 67 was selected. Chicago ARTCC had 334 controllers and therefore a 

schedule with 17,368 controller work weeks (334 controllers x 52 weeks) from 

which a sample of 68 was selected. 

We reviewed work schedules and time and attendance records covering the time 

period August 5, 2007, to August 2, 2008, for each of the controllers in our 

sample. First, we analyzed the original or published work schedule for every 

controller in our sample to determine if the controller was scheduled to work any 

quickturns or any overtime (i.e., a 6-day work week). 

Next, we compared the original or published work schedule to the amended work 

schedule to determine if the controller “traded into” any quickturns. Lastly, we 

compared the amended schedule to the time and attendance record to validate the 

hours actually worked covering a 52-week period. When a discrepancy existed, 

Exhibit A. Scope and Methodology
16

we relied on the time and attendance record to determine what was actually 

worked as it represents the basis for controller official pay and leave. We also 

reviewed time and attendance records to determine if the controller conducted OJT 

during the shift. 

We utilized the results of our statistical sample to project the frequency with 

which controllers were scheduled to work quickturns and overtime and the 

frequency with which controllers conducted OJT. 

We also reviewed fiscal year 2007 and 2008 preliminary and final operational 

error reports for each of the three facilities. During our review, we focused on the 

most severe operational errors, classified as categories A and B by FAA. We 

reviewed the summary of the preliminary operational error report to determine if 

human factors, such as fatigue, were identified during the initial investigation of 

the operational error. 

In addition, we determined the number of personnel involved in the operational 

error, the performance level of the employee involved in the operational error, any 

in-progress training at the time of the error, and the duration of the controller’s 

time on position. Finally, we reviewed the time and attendance records of the 

primary employee involved in the operational error to determine (1) the extent to 

which the controller worked overtime (i.e., 6-day work week), (2) the extent to 

which the controller conducted OJT, and (3) the total number of hours the 

controller worked air traffic during the sample week. 

To identify the measures FAA has taken to mitigate potential controller fatigue, 

we interviewed officials at the national level from the Air Traffic Organization, 

the Civil Aerospace Medical Institute, and NATCA. We also interviewed officials 

at the FAA Training Academy to identify current training methods and future 

training initiatives. Lastly, we attended an FAA-sponsored symposium geared 

toward identifying and mitigating fatigue within the aviation industry. 

Exhibit A. Scope and Methodology
17

EXHIBIT B. ACTIVITIES VISITED OR CONTACTED 

En Route Facilities (Air Route Traffic Control Center)

 Chicago Air Route Traffic Control Center 

Terminal Facilities 

 Chicago O’Hare Air Traffic Control Tower 

 Chicago Terminal Radar Approach Control Facility 

FAA Headquarters, Washington, DC

 FAA Air Traffic Organization, Safety 

 FAA Air Traffic Organization, Terminal and Enroute 

 FAA Training Academy, Oklahoma City, Oklahoma 

Third Parties 

 National Air Traffic Controllers Association Headquarters, Washington, DC 

 FAA-Sponsored Fatigue Symposium in Vienna, Virginia 

Exhibit B. Activities Visited or Contacted
18

Exhibit C. Major Contributors to This Report

EXHIBIT C. MAJOR CONTRIBUTORS TO THIS REPORT 

Name Title 

Daniel Raville Program Director 

Angela McCallister Project Manager 

Annie Glenn Senior Analyst 

Craig Owens Senior Analyst 

Kevan Moniri Analyst 

Natasha Thomas Analyst 

Petra Swartzlander Statistician 

Andrea Nossaman Writer/Editor 
19

APPENDIX. AGENCY COMMENTS 

Federal Aviation 

Administration 

Memorandum 

Date: June 24, 2009 

To: Lou E. Dixon, Assistant Inspector General for Aviation and Special Program 

Audits 

From: Ramesh K. Punwani, Assistant Administrator for Financial Services/CFO 

Prepared by: Anthony Williams, x79000 

Subject: OIG Draft Report: Air Traffic Control: Potential Fatigue Factors 

Thank you for the opportunity to review and comment on the findings and recommendations of 

the subject draft report dated May 26. The Federal Aviation Administration (FAA) concurs with 

four recommendations and concurs in part with one recommendation. 

The following is FAA’s response to each of your recommendations: 

OIG Recommendation 1: Re-evaluate the staffing ranges for Chicago O’Hare once the O’Hare 

Modernization Project is fully implemented to ensure that the range is appropriate and meets the 

new operational needs of the facility. 

FAA Response: Concur. FAA performs yearly reviews of staffing ranges at every air traffic 

facility. If necessary, FAA adjusts those ranges. These ranges are published in the annual 

updated Controller Workforce Plan which this year was published on April 1. Controller staffing 

can be amended for significant changes in the operation regardless of the published ranges. 

OIG Recommendation 2: Approve the recommended changes to FAA Order 7210.3 and 

implement these changes at all air traffic control facilities. These changes include (a) increasing 

the minimum rest period between shifts from 8 to 10 hours, (b) increasing the time available for 

rest after working a midnight shift on the fifth day of a 6-day work week from 12 to 16 hours, 

and (c) allowing controllers to rest during their shift when not controlling traffic. 

FAA Response: Concur. The Notices and Document Change Proposals have been developed and 

are awaiting final internal approval. The FAA expects final action on these documents by 

September 30, 2009, and will provide copies to the OIG upon completion. 

Appendix. Agency Comments 
20

OIG Recommendation 3: Provide mandatory refresher training to controllers annually to 

reinforce fatigue awareness and mitigation strategies. This training should include a 

comprehensive, multi-faceted approach to minimizing employee fatigue. 

FAA Response: Concur. In response to the National Transportation Safety Board’s 

Recommendation A07-31, the FAA’s Controller Training and Development Group, AJL-11 

developed and implemented training on fatigue awareness and countermeasures. A one hour 

lesson was added to the Terminal and En Route initial qualification training program on 

May 20, 2008. All initial qualification students receive this training. In addition, an awareness 

brochure was provided to each controller through their facility on December 1, 2008. Recurrent 

training using computer based instructions (CBI) was distributed to field facilities and a notice 

published making the training mandatory. This notice has been incorporated into the soon to be 

distributed Order 3120.4, “Air Traffic Technical Training.” The initial qualification lesson, 

brochure, and CBI course were updated to include the concept of “sleep inertia.” These updates 

were completed on March 11, 2009. 

OIG Recommendation 4: Expand operational error investigatory requirements to include more 

detailed information on fatigue factors, such as overtime, on-the-job training (OJT), and work 

schedule that could create fatigue conditions to determine whether these factors are a 

contributory cause to operational errors, the frequency in which the factors are occurring, and 

whether or not the existence of the factors indicate a systematic problem. The reports should at a 

minimum include: (a) whether the controller worked overtime during the previous day or worked 

more than 40 hours during the prior work week; (b) the length of time the controller 

conducted OJT, if applicable; and (c) the exact days and shifts worked by the controller during 

the week the operational error occurred. 

FAA Response: Concur. The FAA is actively pursuing significant modifications to its 

processes for identifying, reporting, and analyzing losses of separation including, but notably 

not limited to, those that are currently categorized as operational errors. 

As a fundamental aspect of this effort, FAA will be implementing processes in fiscal year 2010 

to collect schedule data. This data will include time-on-position, shift schedule, and OJT 

instruction time for each person staffing operational positions associated with an identified loss 

of separation for at least a fourteen day period leading up to the event. 

OIG Recommendation 5: Require all facilities to establish procedures to rotate controllers 

through challenging and less demanding positions during each shift to mitigate the potential for 

fatigue to occur. 

FAA Response: Concur in part. The FAA agrees that procedures for directing work 

assignments are required. FAA does not agree that this procedural development should occur at 

the facility level. Adequate procedures were developed at the national level and are included in 

FAA directives including FAA Order 7210.3. Air traffic control facilities are mandated to 

adhere to the provisions of these orders by FAA Order 7210.3 and FAA Order 1320.1. 

Additional guidance on providing relief breaks is contained in Article 33 of the FAA, National 

Air Traffic Controllers Association Contract. In the event that a conflict exists between an FAA 

Order and the contract, the provisions of the contract are followed. 

Appendix. Agency Comments 
21

Appendix. Agency Comments 

FAA air traffic control facilities are properly applying the provisions of these orders as they 

pertain to workload assignments and relief breaks.