Operational Human Factors in UAS (II)

Fatigue and Stress

Fatigue and stress are contributory factors to human error. Therefore, in order to ensure that vigilance is maintained at a satisfactory level in terms of safety, consideration must be given to the following:

• Crew duty times;

• Regular breaks;

• Rest periods;

• Health and Safety requirements;

• Handover/Take Over procedures;

• The crew responsibility and workload.

The work regime across the crew must take this into account.

Degradation and failure

⁃ Degradarion of performance and failures will require a philosophy for dealing with situations to ensure consistent and appropriate application of warnings, both visual and auditory. The philosophy must ensure that:

• The design provides good error detection and recovery;

• The design is fail-safe and protects against inadvertent operator actions that could instigate a catastrophic failure;

• In the event of degraded or total breakdown in the communication link the status of the lost link will be displayed to the operator. Ideally the expected planned reactions of the UA to the situation will also de displayed to the operator.

• Operating procedures are designed to be intuitive, not ambiguous and reinforced by training as required.

Maintenance Human Factors

The set of problems that can initiate Human Factors issues for maintenance teams is not dissimilar to other environments. These include but are not limited to:

• Insufficient time to perform as task;

• Insufficient training and experience to perform a task;

• Inappropriate working environments that can lead to distraction (e.g. noisy offices, multiple demands on individual’s time);

• Fatigue;

• Poor or non-existent working relationships with management and/or other teams.

⁃ Each of these issues can result in a maintenance team making an error and failing to detect it before the aircraft or aircraft system enters service. These errors can result in operational or maintenance problems (system failures, inappropriate maintenance, etc.) and can even drive additional Human Factors issues in other aviation domains such as the flight deck or maintenance.

⁃ Organizations that are developing UASs must ensure that any maintenance Human Factors issues (e.g. provision of clear and unambiguous instructions) are addressed. The means by which this will be achieved must be described to the authority for any proposed certification protect.

Future Trends

Future developments in UAS are moving more towards mitigating Remote Pilot workload through advanced decision support systems. Human Factors expertise will be central to such developments to produce a system that is not only safe but also ensures the correct level of crew workload for all mission tasks and phases of flight.