Fatigue can be described as a physiological state of reduced physical and mental performance capability.
It's caused by four main factors:
Fatigue can affect our ability to perform tasks safely. The more fatigued you are, the more you might find difficulty in maintaining concentration, alertness, or in simply staying awake. Fatigue can therefore increase the risk of errors, which can increase the potential for incidents and/or accidents.
As such, it is important that organisations ensure anyone performing safety-related duties is sufficiently alert.
More information on fatigue is available on human and organisation performance.
Managing fatigue is everybody’s responsibility. Both individuals and organisations need to take steps to manage the effects of fatigue so that it doesn’t result in a safety risk.
Fatigue risk management isn’t a simple task, because there can be numerous causes, many of which are interrelated. These include:
Under the Health and Safety at Work Act 2015, fatigue is a risk that must be managed.
The Act states that organisations are required to make sure their operation is safe (so far as is reasonably practicable), which includes minimising the risk of fatigue. Organisations are required to involve all personnel in managing fatigue. Individuals are responsible for taking sensible safety precautions, for example, ensuring they take advantage of rest opportunities to ensure they remain sufficiently alert for subsequent duties.
One means of minimising flight crew fatigue risk is through the control of flight and duty times. Managing flight and duty time, and complying with it, is the responsibility of both the operator and the crew. Some examples of the types of responsibilities both operators and crew have for managing fatigue effectively are:
Operators are responsible for:
Crews have the responsibility to:
CAA Advisory Circular AC119-2 Air operations – Fatigue of flight crew provides an example FDT scheme for various types of air operations. The example is a complete scheme, and when applied and followed in full is deemed, in principle, to be acceptable.
In accordance with the Civil Aviation Rules, operators can develop their own FDT schemes that, if acceptable to the Director of Civil Aviation, can be implemented as part of the organisation’s risk management provisions.
The alternative VFR FDT scheme for Part 135 day VFR operations within the NZ domestic FIR, provides an example helping operators understand what needs to be considered in developing their own FDT scheme.
This alternative VFR FDT scheme has been reviewed by the Sleep Wake Research Centre at Massey University and found to be scientifically acceptable when applied and followed in full.
The alternative IFR FDT scheme for Part 135/125 IFR operations within the NZ domestic FIR provides an example helping operators understand what needs to be considered in developing their own FDT scheme.
This alternative IFR FDT scheme has been reviewed by Westwood-Thomas Associates and found to be scientifically acceptable when followed in full.
Operators may incorporate either alternative scheme in their exposition without further fatigue management expert input. However, before the scheme can be used in an operation, the CAA MUST assess and approve its implementation.
If an operator wishes to make amendments to an above scheme as drafted, they will need to submit their scheme as amended to a recognised scientific expert for scientific review and endorsement prior to regulatory approval.
When assessing flight and duty time schemes under the current regulatory framework, we apply the Assessment of Flight and Duty Time Schemes Procedure [PDF 236 KB].
This procedure lays out our expectations and the process we currently use to assess schemes that regulate flight and duty times.
It’s important we continue to gain insights into how fatigue can contribute to incidents and accidents. Lessons learned from these events can help improve fatigue risk management in the future.
To identify situations where fatigue could be a risk to safe operations, it’s vitally important the individual(s) involved submit a report and investigate appropriately to adequately resolve unacceptable fatigue risks.
These investigations form an important part of an organisation’s safety system. They also provide valuable information to enable the tracking of any accumulated fatigue issues over time.
CAA Advisory Circular AC12-2 Occurrence investigation provides more information on occurrence investigations. It also provides some specific questions regarding fatigue, to be considered during an investigation.
The International Civil Aviation Organization (ICAO) has set the fundamental standards for fatigue management in aviation. Its website presents an excellent summary on the approaches to managing fatigue, supported by comprehensive resources and guidance. Read about fatigue on ICAO's website here.(external link)
A range of other resources are online. We've collated some of them in the links below:
NZAAA - fatigue risk management programme [DOC 64 KB]
This document provides an example for agricultural aviation sectors and is for reference purposes.