Fatigue Risk Management
Fatigue Doesn’t Violate Limits. It Accumulates Inside Them.
A schedule can comply with every flight and duty limitation in 14 CFR Part 117 and still put a fatigued crew on a dark runway at four in the morning. That is not a flaw in the regulations. It is a limitation the FAA itself acknowledges. Prescriptive limits are a floor, not a defense. Fatigue is a physiological phenomenon governed by sleep debt, circadian rhythm, and time on task, and it does not read the regulations. That is why fatigue risk is managed, not merely limited, and why the FAA, ICAO, and the NTSB have all pushed the industry toward data-driven fatigue risk management as a core component of operational safety.
The Regulatory Landscape
For most of the jet age, airline rest rules were a page of arithmetic written before anyone had measured a circadian rhythm. Eight hours of flight time, a rest clock that ran the same whether the day ended at noon or at midnight, and no distinction between a noon departure and a 2 a.m. one. Crews knew the difference. The rules did not.
Then Colgan 3407 went down outside Buffalo in February 2009 with a crew that had commuted overnight and tried to sleep in a crew lounge. The NTSB had been asking for science-based rest rules for nearly two decades. After Colgan, Congress stopped asking. Part 117 took effect in January 2014, and for the first time the rules knew what time it was: duty limits that shrink for early reports, a protected window of circadian low, cumulative caps, and a fitness-for-duty obligation on both the carrier and the pilot.
What that means for an operator today:
Part 121 passenger carriers fly under Part 117, and every one also owes the FAA a Fatigue Risk Management Plan under §121.473. The plan is not optional paperwork. It is what an inspector, or a plaintiff’s attorney, reads first.
Part 117 is a floor. A carrier that wants to fly outside it needs an FAA-authorized FRMS under §117.7, and the FAA expects real data behind it, not a policy memo.
Part 135 and cargo were excluded from Part 117. Those operators still fly under the older framework, which puts almost the entire fatigue burden on the operator’s own policies and culture. Freedom, and exposure, in equal measure.
Outside U.S. airspace, ICAO’s FRMS standards apply, and they read very much like the FAA’s.
The gap that matters is rarely in the documents. It is between what the fatigue plan says and what the pairings, the reserve practices, and the reporting culture actually do.
What I Do
FRMP Review & Development
For Part 121 carriers, I review fatigue risk management plans against §121.473 requirements and current FAA guidance, and against the operation’s actual pairing construction, reserve practices, and fatigue-report history, which is where plans succeed or fail.
Fatigue Program Development for Part 135 & Business Aviation
Operators outside Part 117 have the most regulatory freedom and often the least fatigue infrastructure. I build right-sized fatigue management programs, covering policy, risk assessment, scheduling practices, and training, sized to the operation and the realities of on-demand flying.
Schedule & Trip Fatigue Risk Assessment
Structured review of pairings, rotations, and reserve structures for fatigue exposure: window-of-circadian-low operations, transmeridian sequences, minimum-rest transitions, and cumulative-duty patterns that are legal on paper and punishing in practice.
Fatigue Event Review
Independent analysis of fatigue reports, fatigue calls, and fatigue-implicated events. This means assessing both the individual circumstances and what the pattern of reports says about the system producing them.
Fatigue Training & Education
Training for crews, schedulers, and dispatchers that goes beyond the regulatory minimum. It is grounded in sleep science, written in operational language, and specific to your operation rather than generic slides.
Fatigue-Related Litigation Support
Where fatigue is at issue in litigation or enforcement, this practice area connects directly to my expert witness work: case evaluation, reports, and testimony on Part 117 compliance, FRMP adequacy, and the operational realities of fatigue.
Why This Practice Is Different
I spent decades flying the schedules these rules govern, international wide-body operations across every time-zone pairing the system can produce, and evaluating crews operating at every point on the alertness curve. My graduate work in Aviation/Aerospace Safety Systems and Human Factors included the science that underlies Part 117: circadian physiology, sleep and performance research, and human error modeling. Fatigue consulting is often delivered by scientists who have never held a duty schedule, or by pilots who stopped at the regulations. This practice exists because the work requires both.
I have also built Zeitfarer, a circadian-adaptation app for flight crew, developing and validating its scheduling model against the peer-reviewed sleep literature. It is independent work, done outside any client engagement, that keeps me current on the underlying science itself, not just the regulations built on it.
How Fatigue Engagements Work
Fatigue engagements range from a focused FRMP review to full program development, and are scoped to your operation’s size, certificate, and route structure. Work is conducted under a confidentiality agreement as standard practice.
Legal Isn’t the Same as Rested.
Every initial conversation is confidential, whether or not it leads to a formal engagement.
Schedule a consult
Practice Areas
© 2026 McCall Aviation Consulting, LLC. All rights reserved.