The NTSB’s finding that fatigue contributed to the February 2009 crash of Colgan Air Flight 3407 set off a three-year regulatory chain. The FAA chartered a rulemaking committee in June 2009, Congress mandated the rule in August 2010, and the final Part 117 rule was published on January 4, 2012.
Part 117 replaced the old flight-time arithmetic with flight duty period tables keyed to report time, segment count, and the window of circadian low — the hours when the body’s sleep drive is strongest.
Colgan Air Flight 3407 went down near Clarence Center, New York, on February 12, 2009. The NTSB‘s investigation identified fatigue in both pilots, and its findings added to the push for new flight- and duty-time rules.
Those findings mattered because the rules governing pilot rest at the time were essentially flight-time arithmetic — a patchwork of domestic, flag, and supplemental limits that counted hours aloft and said almost nothing about when those hours fell.
What followed was not a single regulation but a chain: an FAA rulemaking committee, a statute with deadlines, a proposed rule, and finally Part 117. This is how that chain worked, what circadian science replaced, and what the old and new rules actually say side by side.
From Clarence Center to 77 FR 330: how the rule got written
Colgan 3407 went down on February 12, 2009. Within four months the FAA had chartered its Flight and Duty Time Limitations and Rest Requirements Aviation Rulemaking Committee — June 24, 2009.
The panel handed back its recommendations on September 9.
Congress moved next. Public Law 111-216, the Airline Safety and FAA Extension Act of 2010, was signed on August 1, 2010. Section 212 told the FAA to write fatigue regulations, with a 180-day window for a notice of proposed rulemaking and one year for a final rule.
The agency published its NPRM on September 14, 2010. The final rule — Flightcrew Member Duty and Rest Requirements — ran in the Federal Register on January 4, 2012, as 77 FR 330. That was more than a year after enactment, so the statutory clock had already run out.
Read the sequence plainly and the shape is clear. The crash produced findings, the findings produced a committee, the committee’s work fed a statute, and the statute forced a rule.
The operating tables themselves came last, from the regulator.
What circadian science replaced
Under the old Part 121 framework, a pilot’s legal day was measured in flight hours. There was no general domestic ceiling on how long a duty period could run — the rules counted time aloft, not time awake. Part 117 flipped that. It caps the flight duty period itself, and the cap moves with conditions.
Report time matters. So does the number of flight segments. So does whether the pilot has acclimated to the local time zone. When a duty period falls inside the window of circadian low — roughly the pre-dawn hours — the ceiling drops further.
Actual flight time is capped separately: 8 or 9 hours in unaugmented operations, depending on when the duty period begins.
The rule also stacks cumulative limits on top of daily ones. Section 117.23 sets cumulative flight-time and flight-duty-period limits, with 100 flight hours in any 672 consecutive hours as the flight-time figure. Section 117.25 covers rest, including at least 10 consecutive hours before a flight duty period and at least 30 consecutive hours free from duty within each 168 consecutive hours.
Reserve pilots get their own protections. Augmented crews — those carrying extra pilots and onboard rest facilities — can fly longer under Table C, subject to separate flight-time and in-flight-rest requirements.
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The old limits and the new ones, side by side
Two rows carry most of the story. The first is rest. The former domestic framework required at least 8 hours of rest in the 24 hours before the end of each flight, according to the Federal Aviation Administration. Part 117 requires at least 10 consecutive hours before a flight duty period — a different standard, measured differently.
The second is the missing ceiling. The old framework had no general domestic duty-period cap at all; it leaned on flight-time limits and rest minimums. Part 117’s Table B supplies the cap the old rules never had.
| Rule attribute | Pre-Part 117 framework | Part 117 framework | Source |
|---|---|---|---|
| Maximum flight time per day | Varied by operation; flight-time-based rather than a universal duty-period limit | 8 or 9 hours unaugmented, depending on report time | faa.gov / govinfo.gov |
| Maximum duty or flight duty period | No general domestic duty-period ceiling | Table B limits unaugmented FDPs by report time and segments; Table C governs augmented crews | govinfo.gov |
| Minimum rest | At least 8 hours of rest in the 24 hours before each flight | At least 10 consecutive hours before a flight duty period | faa.gov / govinfo.gov |
| Weekly limit | Domestic: 30 flight hours in seven days; flag: 32; supplemental: no seven-day limit | At least 30 consecutive hours free from duty within each 168 hours | faa.gov / govinfo.gov |
| Monthly limit | Operation-specific quarterly and semiannual limits, not one universal monthly ceiling | 100 flight hours in any 672 consecutive hours, about 28 days | faa.gov / govinfo.gov |
| Annual limit | Domestic: 1,000 hours per calendar year; flag and supplemental: 1,000 hours per 12 months | 1,000 flight hours in any 365 consecutive calendar days | faa.gov / govinfo.gov |
| Circadian or time-of-day limit | No comparable universal time-of-day flight-duty table | Maximum FDP varies with report time; reduced during the window of circadian low | govinfo.gov |
| Cumulative duty limit | Emphasized cumulative flight time; no Part 117-style cumulative FDP structure | Section 117.23 imposes cumulative flight-time and flight-duty-period limits | govinfo.gov |
| Reserve rules | No single Part 117-style reserve framework across the former categories | Reserve transitions covered; 30 hours free from duty per 168 hours before reserve | govinfo.gov |
| Augmentation | No Part 117 Table C structure for circadian-based augmented limits | Additional crew and onboard rest facilities permit longer limits under Table C | govinfo.gov |
| Source: U.S. Government Publishing Office (Federal Register); Federal Aviation Administration (FAA) | |||
Who actually wrote the rule
The FAA controlled the rulemaking from start to finish — convening the committee, weighing what came back, drafting the NPRM, opening the docket to public comment, and issuing the final regulation. Congress set the topic and the deadlines through Section 212 of Public Law 111-216, but the operating tables were the agency’s work, not Capitol Hill’s.
The result was a rule that turns fatigue research into hard limits. Whether a schedule is legal now depends on how many segments a crew flies, whether it is on reserve, how much rest it gets, whether extra pilots are aboard, whether it has acclimated to local time, and when it reports for duty.
And the causal story is messier than the headline version. The FAA’s final-rule record cites earlier NTSB fatigue recommendations and previous accidents alongside Colgan 3407. The 2009 crash pushed an existing reform agenda forward; it did not start it.
What this means for you
For anyone booking a US carrier — including long-haul routes to and from Asia-Pacific — the practical takeaway is that a legal schedule is not the same as a short one. A crew can sit inside its flight-time limits and still be working against its body clock, which is exactly the gap Part 117 was written to close.
Note the scope, though. The rule covers Part 121 passenger operations. All-cargo flying sat outside it, and the sources here don’t say whether that gap was ever closed across the board.
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Key terms
- Part 117
- Part 117 is the FAA’s Flightcrew Member Duty and Rest Requirements rule, which sets how long airline pilots may be on duty and how much rest they must receive. It was published on January 4, 2012, at 77 FR 330, replacing the older Part 121 framework that split domestic, flag, and supplemental operations. Its limits are keyed to report time, segment count, and the window of circadian low, so a schedule that fit inside the old flight-time arithmetic can still be illegal under the current tables.
- Flight duty period
- A flight duty period is the span a pilot is on duty for a flight or a series of flights, running from report time to the end of the last flight. Part 117 §117.3 defines the term, and the rule caps the period itself rather than only the hours spent aloft. The cap moves with conditions — report time, segment count, acclimatization, and whether the duty period falls inside the window of circadian low.
- Circadian low
- Circadian low is the window of the day when the body’s sleep drive is strongest, typically the pre-dawn hours. Under Part 117, a flight duty period that falls inside this window is subject to a lower maximum. The concept is what separates the current rule from the old flight-time arithmetic, which counted hours aloft and said nothing about when they fell.
- Fatigue-risk-management system
- A fatigue-risk-management system is an alternative to prescriptive duty limits in which an operator proposes its own limits and the state approves them. ICAO’s framework separates prescriptive limits — the state’s own ceiling on work and floor on rest — from an approved FRMS. Even with an approved FRMS, baseline maximum-duty and minimum-rest requirements remain in force, so the approach is not a looser standard.
Questions? Answers.
What prompted the FAA to write Part 117’s pilot duty and rest rules?
The February 12, 2009 crash of Colgan Air Flight 3407 and the NTSB’s fatigue findings were the immediate catalyst. The FAA chartered its flight and duty time rulemaking committee on June 24, 2009, Congress passed Public Law 111-216 on August 1, 2010, and the final rule was published on January 4, 2012, as 77 FR 330.
How many flight hours does Part 117 allow within 672 consecutive hours?
Part 117 uses 100 flight hours in any 672 consecutive hours — roughly 28 days — as a cumulative flight-time limit.
What minimum rest does Part 117 require before a flight duty period?
At least 10 consecutive hours of pre-duty rest. The rule also requires at least 30 consecutive hours free from duty within each 168 consecutive hours.
How did the former Part 121 limits compare with Part 117’s framework?
The former domestic framework required at least 8 hours of rest in the preceding 24-hour period, limited pilots to 30 flight hours in seven consecutive days, and capped them at 1,000 flight hours per calendar year. Part 117 replaced that with 10 consecutive hours of pre-duty rest and 100 flight hours in any 672 consecutive hours, among other limits.
Under ICAO’s approach, does an approved FRMS eliminate baseline maximum-duty and minimum-rest requirements?
No. ICAO describes prescriptive limits as maximum work periods and minimum non-work periods set by the state, and an approved fatigue-risk-management system does not eliminate those baseline maximum-duty and minimum-rest requirements.
