Workload and helicopters

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Interior of helicopter cockpit
image: © Airbus Helicopters

Rotary-wing pilots have to manage engines, rotors and their own mental reserves.

‘It flies itself’, said no helicopter pilot, ever. Piloting a helicopter is a complex, continuous, multi-task operation, in no small part because of helicopters’ inherent and dynamic instability. This means helicopter pilots face a high workload in day-to-day flying, with a peak workload in hovering. In her 2008 publication Human Performance, Workload and Situational Awareness, human factors specialist, Dr Valerie Gawron, says the ‘workload of a helicopter pilot in maintaining a constant hover may be 70 on a scale of 0 to 100’. Rotary-wing wags have an earthy but arresting description saying the same thing: hovering is ‘like making love in a hammock standing up’.

The US Federal Aviation Administration (Advisory Circular 23.1523) defines workload as ‘the relationship between an individual’s capacity to perform a task (mental and/or physical) and the level of system and situational demands associated with the performance of that task. Tasks that demand much of the human resources (capacity) are high workload tasks. And importantly, ones that demand little human capacity are low workload tasks.’

There are various ways of measuring workload, including the Bedford workload scale and the NASA task load index (TLX) based on pilots’ subjective evaluations of their workload. Objective measurement includes data on pilot behaviour such as the time taken to perform a task, error rates, and the number of actions performed; as well as sensorimotor activity (eye-tracking, number of head movements) and physiological measurement via electrocardiograms (ECG) and respiration rates. The chief problem with such data is that it is mainly gathered from simulator flights, and therefore subject to the limitations of scenarios not being ‘real’.

Given the inherent instability of helicopters, rotary pilots have a greater than average workload, but according to David Lamb, a test pilot and rotary specialist with CASA, many helicopter pilots do not have a good understanding of workload, the consequences of increasing workload, and what this workload means for their safe performance. They see it as a challenge and a deficiency in their own ability. Their tendency, Lamb says, is to ask ‘“What’s wrong with me?” They see such issues as a function of their inability to complete the task, rather than considering workload as an extension of the flight envelope of the aircraft, for which there are defined limits’.

Just as there are manufacturer-defined limits to safe flight—the physical limits of structural, aerodynamic, powerplant, transmission or flight control capabilities—so Lamb says, helicopter pilots should consider workload in the same light. They should ask themselves, ‘What spare capacity do I have to cope with the unforeseen and unexpected?’ Unfortunately, ‘when you go into the red, there is no gauge to tell you that’.

What factors affect workload?

Workload varies according to the stage of flight, as the accompanying diagram illustrates. The times of high exposure are take-off and landing, complicated by factors such as CTAF management. The prime way for pilots to manage workload is by pre-flight planning, Lamb says, because during the flight excess workload can creep up on pilots. ‘It’s a bit like fatigue; insidious, and the question you need to ask yourself is “how engrossed am I in this task?” If you are engrossed, for more than a few minutes, that’s a danger sign.’

  • Workload also varies temporarily, according to weather (IMC, wind/turbulence) and environment (terrain, obstacles, wires).
  • The capacity to handle these factors is further complicated by recency, proficiency (both in skills and knowledge) and attitude. To manage workload you have to ask some stark questions: How recently have I flown this type, this particular flight? How many hours do I have, and are they multiples of the same hour/the same experience, or do these hours represent a variety of conditions and challenges?

Some strategies for managing workload

  • ‘Workload can be shared temporarily by not doing a task,’ Lamb says. In the case of the 2011 Lake Eyre night VFR fatality, for example, the issue of ‘correcting the fly-to point in a GPS unit’ could have been dealt with at top of climb, instead of during a time of ‘high pilot workload associated with establishing the helicopter in cruise flight’.
  • Shed the unimportant tasks, and accomplish the essential operations by planning. Prioritise them in a sequence that avoids work overload.
  • If you recognise you are becoming task saturated or overloaded:

– stop
– think
– slow down
– prioritise.

  • Staying separate to the task can help in maintaining the mental distance necessary for managing workload. The old test pilot’s trick of visualisation can also be useful. Aerobatic pilot Matt Hall’s preparation for races is highly structured, blow-by-blow, second-by-second. Hall described his technique to Flight Safety Australia. ‘I’ll sit down and pull the whole flight apart. For a seven or eight-minute flight, I’ll maybe have 10 pages of notes, second-by-second of what I’m doing. I’ll write it all down … almost like a script; then I’ll learn the script. I’ll start flying it “slow time on the ground”, and then I’ll start flying it real time. That’s the big thing I learned in the air force: preparation techniques; mental techniques; and visualisation.’
  • Remove ‘probably’ from your vocabulary. Max Trescott, American CFI and ground instructor and winner of the 2008 US CFI of the year, contends that ‘probably’ means we’ve done an informal assessment of the likelihood of an event occurring and have assigned a probability to it. He believes the term implies that we believe things are likely to work out, but there’s some reasonable doubt in our mind. If you think your course of action will ‘probably work out’, you need a new option that you know will work out.
  • Checklists are essential cockpit resources, but … you need to plan how you’re going to use them. Slavish adherence to completing a detailed checklist can add to workload in an unexpected situation or in an emergency.

These strategies are especially applicable to a single-pilot operation in an unaugmented helicopter. Workload in such simple, non-automated helicopters will always consume a significant portion of a pilot’s spare capacity depending on the task.

Stability augmentation systems (SAS), so called because they stabilise the helicopter against outside influences and augment, or help, pilot input, are now available for light helicopters, such as the Bell 206 and 407, and the Eurocopter AS350 and EC130 series. They support hands-on flying, and reduce pilot workload, especially in the critical hover. Autopilots provide the next level of pilot workload reduction, enabling hands-off flying.

But technology can be a two-edged sword. The complexity of some IFR-equipped helicopters, for example, can require more than one set of eyes and hands to be used to maximum advantage. And just as in the fixed-wing world, the automation designed to reduce workload paradoxically can add to workload if it malfunctions, or in abnormal situations, because of decay of pilot skills and unfamiliarity with hands-on flying.

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