I bring you a weekly bite-sized chunk of the science behind helicopter human factors and CRM in practice, simplifying the complex and distilling a helicopter related study into a summary of less than 500 words.
TITLE:
The physiological demands of helicopter winch rescue in water and over land.
WHAT?
Study quantifying the physical workload experienced by helicopter rescue winch paramedics during demanding land and water winch-rescue tasks. It measured how close rescuers were working to their maximum aerobic capacity and estimated their maximal acceptable work duration (MAWD) (the period for which a workload can reasonably be sustained before fatigue could compromise performance).
WHERE?
Victoria, Australia.
WHEN?
Published in the journal Ergonomics in 2022.
WHY?
The physiological demands of helicopter winch rescue had not previously been quantified. The researchers wanted objective evidence on which to base selection and physical employment standards (PES) and to understand how long rescuers could safely sustain these workloads before fatigue potentially affected performance.
HOW?
14 Flight Paramedics averaging 44 years of age and seven years’ experience completed realistic simulations of two operational tasks. The land rescue involved carrying 43.4 kg of equipment 250 m up an 18.3% rocky incline. The water rescue involved swimming to a life raft while connected to a simulated winch cable, extracting a 50 kg manikin and towing it to safety.
Researchers measured oxygen consumption (VO₂), heart rate, blood lactate and perceived exertion, comparing these with each participant’s separately measured maximum aerobic capacity.
FINDINGS:
The demands were greater than the researchers anticipated. During the land task, rescuers worked at an average 86% of VO₂peak for 7 minutes, with peak heart rate reaching 93% of maximum. In the water, the task required 81% of VO₂peak for 10.2 minutes.
These represented approximately 53% and 48% of estimated MAWD, respectively.
The authors conclude that helicopter rescue personnel operate at very high physiological workloads for meaningful periods, considerably exceeding demands reported for some comparable occupational tasks.
SO WHAT?
Physical fitness in helicopter rescue is a human-performance and operational-safety variable. A rescuer may reach a casualty under substantial physiological load, yet still be required to provide clinical care, solve problems and coordinate with the aircraft and crew.
The results support job-specific, evidence-based fitness standards rather than generic fitness testing. They also have operational implications as repeated rescues can create cumulative fatigue. The authors estimated that rescuing more than four people in the water could exceed calculated MAWD. This could inform decisions about crew fitness, task rotation, recovery and deployment of additional helicopter resources during multiple-casualty rescues.
REFERENCE:
Meadley, B., Horton, E., Perraton, L., Smith, K., Bowles, K.-A., & Caldwell, J. (2022). The physiological demands of helicopter winch rescue in water and over land. Ergonomics, 65(6), 828–841. https://doi.org/10.1080/00140139.2021.1998645
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