In recent times, the Norwegian Air Ambulance Foundation conducted an extensive research project over a three-month period, comparing the operational and medical advantages of the short-haul HEC (human external cargo) and hoist methods of HEMS rescue services to establish the safest, most effective and efficient methodology for future Norwegian HEMS operations.

Foundation

Since 2018, and operating from some 13 bases, Norwegian Air Ambulance has exclusively conducted Norway’s Helicopter Emergency Medical Services (HEMS ). A subsidiary of the non-profit Norwegian Air Ambulance Foundation, it is under contract to the publicly funded and state-owned Air Ambulance Services of Norway. The foundation owns and operates the very first production Airbus H145-D3, serial #21001 in a red paint-scheme that differentiates it from the yellow aircraft of the active air ambulance service. Fitted with a Goodrich hoist for the purpose of the HEC vs. hoist study, it is available to be used for the foundation’s varied research and development projects and crewed when required by pilots and crewmen from the subsidiary helicopter operating company.

Matts Callisen who is the project Manager from the foundation’s operational staff explained that the foundation is funded by significant donations and sponsorship, with around 30 million Euros raised last year, enabling it to undertake its extensive and costly research operations. It takes a very long-term view and conducts projects such as a ground-based mobile stroke unit, with the view to eventually transitioning any advances from the ground to the aerial environment.

 

HECS Study

Always looking to research and develop better ways to deliver HEMS, ambulance and healthcare services outside the hospital environment, the foundation recognized that the previous and almost exclusive reliance on HEC operations may not be the most effective methodology going forward. “We have used the HEC method since 1978, mainly unchanged over that time apart from the rope lengths and where they’re attached to the helicopter. We have a lot of experience with it and it’s a robust method that works well. When we look at sister HEMS operations around Europe however, they transitioned to hoisting many years ago and have a lot of experience hoisting with the H145 platform,” related William Ottestad who is the PHD leading the project, and is also a Senior Researcher with the Air Ambulance Foundation and a Consultant Anesthesiologist of the Air Ambulance Dept at Oslo University Hospital.

A retrospective analysis conducted by Swiss Air-Rescue (Rega) covering the period from 2010 to 2019 documented 11,228 successful hoist operations, none of which resulted in procedure-related injuries or adverse events affecting patients or crew members. “Because that illustrated that hoisting in a HEMS operation could be safe and efficient, we wanted to explore whether it would be a better tool for us in the future, with the goal of making recommendations to the health authorities in that regard.” While accepting that experience and knowledge gained from other operations can provide valuable insight, the specific nature of Norway’s terrain and established crew concepts dictated that a thorough assessment had to be conducted in a proper scientific manner.

“There are always some differences and we wanted to see if hoist use could be adapted to our particular situation,” stated William. He explained that the study has been a massive project that has taken three years in total and is just one of several studies in which the foundation is engaged. Other European operators fly crews of up to four people, with a pilot, hoist operator/rescue tech’, the doctor who goes down on the wire and a specialist climber if appropriate for the terrain and mission. However, the foundation wanted to retain its three-person crewing system for HEC rescues, where the rescue technician goes down to the victim and the doctor operates as the doorman and directs the pilot.

 

Crew Concept

There is some skepticism within the industry about the reliance on doctors as hoist operators, due to the lack of a typical selection process for that role among flight crew members, requiring spatial orientation, hand-eye coordination and multi-tasking capability. “Because our doctors are well-trained to direct the pilot and work as the doorman, however, we thought that they should be able to translate that into the hoist operator’s role,” William commented. Of course, a doctor’s normal workload demands multi-tasking and operating in high-stress, time-critical work environments so their existing skillset fits in well with the demands of the HEMS role.

Erik Norman is the foundation’s chief pilot as well as an operational air ambulance pilot, splitting his time evenly between the two roles. He explained that the Norwegian rescue technicians are broadly skilled in mountain guiding and alpine rescue, as well as receiving simulator training in flying the helicopter to add an extra level of safety to missions. “They’re not licensed but we let them fly with us so they can fly the helicopter well enough to get home and land if something happens to the pilot,” he stated. “They’re all qualified nurses or paramedics before they start with us and then they get further training for their specific tasks in supporting the doctor.”

Norman commented that he found the entire process of the comparison study to be highly interesting, particularly in how it replaced subjective opinion with provable data sets. “I think hoisting is a more flexible method but just because I think that, it doesn’t mean I can justify or prove that opinion,” he acknowledged. “When we bought the H145-D3, we bought it with a hoist because we’ve worked with Rega and Air Zermatt and they do a lot of alpine hoisting, so we thought we should be willing to learn from their experience.” Because he was a part of the study, Norman was not privy to any of the results until very recently, but he has since observed that the doctors involved seemed to find that the workload was lower on the hoist operations, a sentiment echoed by Norman himself from a pilot’s perspective. “The doorman has to rely on the pilot for everything on HEC missions but as a hoist operator, he has control over things like the height above ground and the speed of retrieval,” he pointed out.

 

Study Methodology

The study commenced in 2024 after careful planning to develop suitably accurate methodology. “First off, we educated five pilots, four rescue men, six technicians and seven hoist operators, four of which are doctors,” William outlined, pointing out that while everyone was highly experienced in HEC, no one involved had previously done any hoisting whatsoever. “We went to other experienced operators – notably Rega and Air Zermatt – to educate our instructors and we have done approximately 2,000 cycles and a motor time of around 100 hours of hoisting.” Rega, in particular, was extremely helpful, operating the same H145 platform as the foundation and its procedures were used as a starting point from which to develop the foundation’s. “When we designed the study, we wanted to make it as realistic and close to a real rescue mission as possible. We set up a temporary base on the north-west coast because all the terrain types are within close proximity of the airport. We stayed at that base for five weeks this year in March, June and September, to include winter, spring and autumn conditions. We encountered variable and challenging conditions at times, with high winds, low temperatures and even some snow.”

Several rescues were programmed in alpine terrain on the north-west coast, after careful reconnaissance and planning. The rescue sites were divided into four generic categories: dense forest, sheer vertical faces, deep gorges and exposed alpine terrain such as peaks and ridges. “In the forest and gorges, they were picking up pre-placed rescue bags and for vertical and alpine locations, we simulated the rescue of a climber secured to the cliff face. This scenario is particularly dangerous because once the victim is attached to the helicopter, the helicopter itself is temporarily anchored to the cliff until the climber’s original anchor can be safely disconnected. Throughout this critical phase, the rescuer maintains continuous communication with the pilot, clearly signaling when the helicopter becomes anchored and when it's released. Minimizing the duration of attachment is crucial, typically lasting around three seconds.”

 

“We recruited four pilots, three doctors and four rescuers for the study – all actively working within our Norwegian HEMS community,” William advised. Each morning of the study, the crews attended at the base operations room and drew a random selection from a pool of available missions. Every mission was pre-planned, and the crews were given the location of the rescue and the rig-site for planning the sortie, using google earth and a HEMS application that enables terrain analysis, weather and other relevant information. The dispatch requirement was that the crews be airborne within fifteen minutes of drawing the mission.

The decision whether to use hoist or HEC on the first mission was decided by a coin-toss application and after completing that first sortie, the crews returned to base for about fifteen minutes, debriefed while the aircraft was fueled to the same weight and then immediately re-flew exactly the same mission using the alternate method. The reason for the short period on the ground was so that both sorties for a particular mission were flown in virtually identical conditions. For each subsequent mission, the order of methods alternated from the previous one. The methods for each mission alternated in order to avoid bias due to learning effects – making the second execution easier – and switching the order prevented that learning effect from affecting the study results.

 

After both sorties had been flown for a particular rescue mission, the crew drew another random mission and followed the same process but reversed the order of hoist and HEC. All scenarios were flown during the day and three or four different rescue missions were flown on each day of the study’s five weeks of flying. The study involved a total of 124 missions – 62 with the hoist and another 62 with the rope – flown by eleven different crew compositions. Each crew member was equipped with health monitors during the study flights to track and record physiological variables, including heart rate and heart rate variability, enabling an assessment of physical activation. Additionally, the NASA Task Load Index, a multidimensional assessment tool, was utilized to evaluate the crew's perceived workload. Stress and workload data was taken for three mission phases; the reconnaissance, rescuer insertion and rescuer extraction.

Differences

A major difference between the two methods is the necessity to always locate and land at an intermediate rig site when conducting HEC operations. The helicopter has to land and rig up the HEC line, taking approximately ten minutes before taking off again for the actual rescue. In good weather, a hoist can be flown with the hoist operator already in the back, thereby eliminating the need for an intermediate landing at a rig-site. For the study however, every flight was flown the same way, with both flight crew members in the cockpit for an initial reconnaissance, followed by a landing at the intermediate site for the hoist operator to get into the rear cabin. During the study, underslung transits of up to nineteen minutes were recorded between rig site, rescue location, and back to rig site, during which the HEC rescuer was exposed at the end of the rope and the pilot had the significant responsibility of flying with a person suspended beneath the aircraft for that period. Additionally, a fixed-length HEC line limits the pilot’s ability to adjust vertical position above target, whereas a hoist operation allows greater flexibility in positioning the aircraft to mitigate turbulence, improve visual references and avoid glare.

 

William explained that the study endpoints were elapsed mission time, exposure time for the rescuer beneath the aircraft, workload, operational precision and flight data parameters such as fuel flow, control inputs and peak torque. Workload was measured not only by the monitoring of physical data, but also by a subjective method in which crewmembers rated their perceived loads in the mental, physical, temporal, frustration, performance and effort categories. The precision of rescuer insertion was measured by four cameras on the aircraft, in reference to either known reference points or chalk-spray marks on the ground.

Results

 

Although the study is now complete, the results are to be peer reviewed before they are published, probably at the end of 2025 and so nothing is yet being released. Nevertheless, William is enthusiastic about the conduct and eventual results of the study, commenting, “Now we have all the data for all those endpoints, we can analyze it to determine what you will gain or lose when you transition from between HEC and hoist operations, in terms of efficiency, rescuer exposure, workload, stress and fuel consumption etc. It’s not rocket science but it’s a lot of work and I think it’s pretty novel. No one has done it before and it can give us some valuable information. The crews were really happy with the design of the study, they’ve learnt a lot and it’s been great training for them.”

This study is not the end of Norwegian efforts to improve HEMS. Norman remarked that some work is still to be done on establishing the optimum maintenance procedures and processes to keep a hoisting aircraft fully mission-ready in a cost-effective manner, while in the pipeline for future consideration are night hoisting, extended hoists and simulator-based hoist training. He opined that his personal take from the study is that hoisting is a more flexible and safe option compared to HEC in many circumstances. It gives the pilot the option of establishing a low hover when a landing is impractical, using a very short hoist to safely and quickly deploy a rescue tech’ and recover a victim. It eliminates extensive transits with a rescuer and/or victim on the end of the rope in extreme cold, with the pilot stressing over their safety.

William remarked that the doctors participating in the study demonstrated competence and effectiveness as hoist operators, addressing and potentially alleviating earlier concerns raised by skeptics “The learning curve for the hoist was pretty steep but once we got through that, we got very comfortable with hoisting, really fast.” He commented that the Norwegian HEC and hoist procedures have been fine-tuned to be as similar as possible so that it is now fairly straightforward for the crews to transition from one method to the other. Norman concluded, “I can’t think of a better aircraft for mountain rescues than a H145-D3 with a hoist but talking only takes you so far. That’s why it was so important to go through this exercise and show how well it works. It’s all a matter of getting a sick or severely injured person out of a bad situation as quickly, safely and efficiently as possible.”