Flying medical transport missions comes with specific conditions in the cabins of the aircraft that respond to the calls. The domain of airborne intensive care has developed significantly since its origins in the 1990s. In this feature on airborne intensive care units (ICUs), we have reached out to industry experts for an overview of specific requirements, the trade-offs needed and best practices for conversion and configuration.

Specific requirements

The needs of intensive care patients are manifold, affirmed Wolfgang Voelckel, Chief Medical Officer at ÖAMTC-Flugrettung. “While some require rapid airlifting without advanced in-flight care, in other cases ongoing life support, employing high-tech medical devices, must be accomplished. Thus, every flight mission is different and must be individualized and adjusted as needed,” he observed. “Moreover, intensive care transports can be split in two different phases: patient transfer from the ICU bed to the helicopter and vice versa, and in-cabin patient care. Size, weight and operability of the stretcher must be merged with the cabin configuration. The latter defines the options of in-flight patient access and how life support devices can be secured and operated during flight.”

Today, the range of operations is much broader and more complex than in the 1990s, when intensive care transport was still in its infancy, therefore helicopter cabins must meet even more specific requirements, said Florian Würtz, Head of the Medical Technology department at DRF Luftrettung. “First of all, cabins must offer sufficient space for the large number of medical devices, including standard equipment (ventilators, patient monitoring systems for vital signs, and syringe pumps) and possible special equipment (extracorporeal membrane oxygenation (ECMO), intra-aortic balloon pump (IABP), Impella heart pump, and, in the case of newborns or premature babies, transport incubators),” he said. “Secondly, it may be necessary to transport bariatric patients who require more space due to their larger body volume. They may also need to be specially positioned (for example in a prone position).”

Design considerations are made with the customer’s requirements at the forefront of the process, added Florian Müller, Business Development and Marketing for Air Ambulance Technology. “Our medical interiors are tailored specifically to the needs of our customers depending on their mission profiles. At the beginning of the design process, we always try to understand which daily missions the operator needs to complete. With that information we propose the most suitable equipment to the client with which he can perform his everyday task to save lives,” he said.

As well as specificity for missions, the interiors need to be designed in such a way as to allow the crew to use that space and for a patient to be able to treated in that space, explained Rolf Kraus, Director of Sales and Programs MIC at Bucher: “The primary considerations for a medical interior are ergonomics, accessibility, and compatibility with critical medical equipment. The layout must enable the crew to perform tasks efficiently during high-stress situations while ensuring patient safety and comfort. Power distribution, oxygen systems, and secure mounting for medical devices are crucial. Weight optimization and compliance with airworthiness regulations also play a significant role in designing medical interiors.”

The roll-in stretcher system is designed to transport patients, some weighing over 200kg, plus all connected medical equipment between the helicopter and the hospital, taking patient and staff safety into account

There are also increased technical requirements for the medical interior of helicopter cabins, explained Würtz. “The roll-in stretcher system is designed to transport patients, some weighing over 200kg, plus all connected medical equipment between the helicopter and the hospital, taking patient and staff safety into account. In addition, a sufficient amount of oxygen must be carried on board,” he said.

Tony Mueller, Director of Government and Fleet Sales at Pilatus, concurred: “When outfitting a medical interior, we focus on optimizing space, functionality, and safety. The size, weight, and power requirements of the medical equipment certainly influence the design – these factors determine placement, integration, and power sourcing within the aircraft. Each medical interior is tailored to meet specific mission requirements, whether it’s for air ambulance transport, critical care, or other medical operations. While there are universal components like stretcher systems, oxygen setups, and storage for medical supplies, customization is key to ensuring that everything from equipment to patient comfort is addressed. Every mission can have different needs, so we work closely with medical operators to design interiors that serve specific patient care scenarios.”

The goal is to always give every patient the best possible treatment, and for this there is a need of medical equipment and restraint systems for crew, patient and equipment, affirmed Lena Schubert, HEMS Engineering Manager at ADAC Luftrettung. “The medical equipment and the electrical devices are chosen by regulatory specification. This can vary by the different mission specifications and ambient conditions and also applies for the climate control in the cabin to support the medical treatment. The regulatory requirements are the minimum; where we have the freedom to choose specifications, we always try to opt for state-of-the-art in science, in technology, and also check out innovations,” she said. “All the restraint systems need to be engineered and manufactured by an EASA Part 21 Organisation to make sure they do not interfere with each other, the emergency exits, and the helicopter. This applies also for the cabin lighting, as well as the electrical and oxygen systems.”

When patients are involved, the whole mission journey needs to be considered, and the specific needs of the patient and potential patients that are being transported. Horst Heinicke, VP of International Sales at Spectrum Aeromed, explained the company’s approach to this aspect: “Regardless of whether the operation is VIP or non-VIP, our priority is always the full cycle of patient treatment. This includes the loading and unloading process and ensuring seamless onward transport to and from the hospital. We begin by identifying the mission requirements. For example, will the aircraft be used for ICU or non-ICU operations? What are the typical destinations and resulting oxygen and storage requirements? Are there preferred medical devices the customer would like to be integrated? If the customer already has an aircraft, we assess its suitability for their needs. Otherwise, we can consult on the most appropriate platform for their operation.

“We also ask early on if the aircraft will need to support multiple roles, such as VIP, executive transport, ambulance, or other mission equipment.

“The choice between a permanent or quick-change installation is another critical factor. Quick-change installations, which are increasingly popular, now allow for intensive care transport, neonatal transport, and even the transport of highly infectious patients.”

Quick-change installations, which are increasingly popular, now allow for intensive care transport, neonatal transport, and even the transport of highly infectious patients

Kraus agreed, stating that planning for multiple contingencies is the key to a viable interior: “Compatibility with diverse equipment is essential for medical interiors to handle various scenarios effectively. Ensuring sufficient power supply, space, and mounting options for devices such as ventilators and defibrillators is critical. Plug-and-play systems, as seen in Bucher’s flex interiors, simplify integration and provide the versatility needed for seamless operation across different missions and equipment setups.”

This was also a sentiment felt by Müller: “We are not only helping customers with the most common aircraft but also clients with older types or very exotic aircraft. We can cater to the needs of various clients, no matter how niche the airplane or helicopter is.” He continued: “Our kits are widely compatible with a large range of devices. Especially in the design process of a medical interior, the consideration of the medical devices is crucial. According to this information we know how much power we need to supply or if we need to install a dedicated oxygen supply system.”

Adding a medical interior to an aircraft means that the medical aspect of the craft needs to be taken into account in a wider context. Mueller explained that servicing and maintenance is an extra factor involved: “Medical aircraft generally require special maintenance schedules. While the base maintenance for the airframe, engines, and avionics follows standard procedures, the medical equipment and interior will have specific upkeep requirements. The medical equipment, such as patient monitoring systems, oxygen equipment, and life support systems, must be regularly checked and serviced according to medical and aviation standards. Pilatus ensures that maintenance providers are trained in the unique needs of medical aircraft, and we support operators with maintenance schedules, parts availability, and technical support to keep both the aircraft and medical equipment in optimal working condition.”

Knowing that a level of flexibility is needed in medical missions, Bucher has designed interiors for the H135 and H145 in a modular way, said Kraus: “They offer quick-lock stretcher systems, medical racks, and storage solutions that optimize cabin space while maintaining accessibility. The flex interiors excel in adaptability, allowing operators to configure the interior to suit various medical missions without compromising functionality or safety. Both product lines prioritize lightweight materials and user-friendly components, ensuring compliance with airworthiness standards and operational efficiency.”

Trade-offs needed

When thinking about new equipment to improve the possibilities for treatment or to make working inside the helicopter safer or more practical for the crew, it must be air law first, emphasized Schubert. “The equipment needs to comply with existing air law and the regulatory requirements relating to the approval of the helicopter itself and the permission for every specialized operation like helicopter emergency medical services (HEMS), helicopter hoist operations (HHO), or night vision imaging system (NVIS). At the same time it is always necessary to check new equipment on the helicopter regarding the space to move for the crew and the usability of the equipment,” she said. “It is also necessary to consider the medical needs and check what the best solution is regarding the space and weight. Consideration must always be given to follow-up assignments. For this reason, it should be as easy as possible to convert the cabin for different missions.”

Consideration must always be given to follow-up assignments. For this reason, it should be as easy as possible to convert the cabin for different missions

The limitations that prevent aircraft from enjoying all the space and weight that an emergency unit in a hospital experiences means that there are certain designs and alternative materials that have to be considered, said Kraus: “Airworthiness regulations and the physical constraints of the airframe can impose limitations. For example, certain configurations might not be feasible due to weight restrictions or space limitations, especially in compact aircraft like the H135. However, advancements in lightweight materials and modular designs have significantly reduced these trade-offs. While most medical transports and transfers are achievable today, highly specialized equipment setups may require tailored permanent installations to optimize performance within the available space.”

Dedication to safety is a primary motivator for much of the aviation industry, and medical interiors is no exception, added Müller: “Our highest priority is to build EMS and VIP equipment which adhere to the highest safety standards. This means that sometimes there are certain trade-offs which are needed to satisfy the regulatory requirements from the aviation authority. However, our experience of the last 30 years proves to be a huge advantage as we know how to push the existing certification boundaries in the interest of our customers.

“The shape of the airframe certainly restricts the room which we can allocate for the equipment, the patient and the crew. In order to save space, we developed a compact medical rack which leaves more room for the patient and the crew.

“Reducing the weight of our equipment is another very important aspect we constantly think about. An increased payload means for the operator a reduced range. This certainly makes a difference for those who operate on long-distance flights with limited possibility for refueling,” he concluded.

Making sure that the airframe and the interior and equipment work together is an essential requirement on a mission-to-mission basis, and something that Spectrum takes seriously, said Heinicke: “Compatibility is critical. Our equipment is used globally, and one of the key advantages of Spectrum Aeromed’s systems is that we customize power sources, outlets, interfaces, and medical equipment to meet specific local requirements. This ensures that our customers can quickly adapt to last-minute changes in medical crew or mission equipment, providing them with unmatched flexibility.”

For intensive care transports, the patient and the equipment are usually well prepared (accessibility, line management, etc.) and, at best, only a few interventions need to be carried out during flight, affirmed Schubert. “The cabin must therefore also function as a treatment room and be optimally designed for this purpose. Attention must be paid to the best possible ergonomics for the crew, who also have different requirements, for example due to their different heights,” she said.

Attention must be paid to the best possible ergonomics for the crew, who also have different requirements, for example due to their different heights

Trying to make sure that all factors are considered is difficult, and requires specialist knowledge and use of the right materials that are suited to multiple situations, said Mueller: “There is often a balance between comfort and functionality when designing a medical interior. While we do prioritize patient comfort, it is equally important to create an environment that can be easily cleaned, sanitized, and kept sterile. This means using materials that are resistant to contamination, non-porous surfaces for easy disinfection, and configurations that facilitate quick cleaning. While the layout and design ensure that medical professionals can operate efficiently and safely, the overall aim is to maintain a balance where patient care is optimized without compromising on cleanliness and sanitation standards.”

When DRF Luftrettung crews are dispatched for intensive care transport missions, a detailed mission planning is carried out, explained Würtz. “This includes both flight preparation and the mandatory physician-to-physician consultation between the source hospital, our emergency medical colleagues and the destination hospital,” he said. “This involves discussing the patient’s condition, any special features, the equipment required, the deployment logistics (is an intermediate transportation to the landing site necessary?) and the urgency.”

As regards regulatory requirements, cabinet systems, oxygen systems and equipment holders (i.e. everything relating to the medical workstation in the cabin) must have airworthiness approval – usually in the form of a supplemental type certificate (STC), highlighted Würtz. “If there is no airworthiness-approved equipment on the market, we can implement and approve modifications as part of our own EASA Part 21 Design Organisation – either as an STC or as a ‘minor change’,” he said. “The remaining regulatory requirements relate to the approval of the pieces of equipment as medical devices (CE labelling).”

The added layers and levels needed from compliance with airworthiness and medical rules mean that there is a complexity that takes time, expertise and dedication to get right, added Heinicke: “Beyond compliance with Federal Aviation Administration (FAA) or European Union Aviation Safety Agency (EASA) regulations, we must also factor in medical device regulations, such as CE marking. These requirements introduce additional complexity to system design, often influencing the choice of components and materials. Extended testing, clinical studies, and continuous product monitoring can lengthen certification timelines and add unexpected costs. The shape of the airframe, space, and weight can sometimes impose limitations. However, with our deep understanding of today’s certification requirements and experience in medical system design, we can often find innovative ways to work within these constraints. By involving us early in the process, we help keep costs and timelines under control while delivering solutions that meet both regulatory and operational needs.”

Regulations are not standard the world over, so making sure your interiors are compliant and safe internationally is a challenge that requires thought and consideration, explained Mueller: “Navigating the regulatory landscape requires careful coordination between aviation and medical authorities. In aviation, the aircraft must meet stringent certification standards set by relevant authorities, such as the FAA in the USA or EASA in Europe. This regulatory framework can vary by region, as each country or area may have its own specific requirements for medical transport and emergency medical services. Pilatus collaborates with partners to ensure that all necessary certifications are obtained and that the design complies with both aviation and medical safety standards.”

Where to convert and configure

To convert or configure a helicopter for air medical missions means additional electrical power, light and oxygen installations in the aircraft are needed, explained Schubert. “The conversion can only be done by a qualified EASA Part 145 [Organisation] in accordance with approved data [constructed] by a qualified EASA Part 21 Organisation,” she said. “Special mission equipment, such as special mission radio to contact other action forces and additional warning units because emergency helicopters normally fly in very low heights, are also needed.”

The crew can modify the equipment on their own without tools (on a quick-release basis) and without a technician. This means that different configurations can be flown depending on the mission

A best practice is to furnish helicopters with basic emergency medical services (EMS) equipment, such as electrical system, oxygen lines, extended lighting, sealed and partially reinforced floor, explained Würtz. “This is then supplemented with additional modules depending on the application profile. These include sliding and rotating seats, cabinet and stowage systems (cabinets, stowage modules), holders for oxygen cylinders (oxygen racks), rail systems (medical equipment racks or rails) for medical device holders and the medical device holders themselves (medical device retainers, mounts),” he said. “The crew can modify the equipment on their own without tools (on a quick-release basis) and without a technician. This means that different configurations can be flown depending on the mission. One example is patient transport with ECMO. If the crew is requested for this special mission, they can adapt the interior to the specific requirements of the mission within a short time.”

In daily practice, in-cabin configuration for air medical missions will be adjusted before flight according to the patient needs, affirmed Voelckel. “To match with the evolution of medical technologies, manufacturers of HEMS interiors are required to further develop and certify easy-to-adjust devices,” he concluded.

Adjusting your platform to the mission ahead allows for greater flexibility of operations, and having an aircraft and an interior that is suited to this is beneficial for an operator that offers a range of services. “A key advantage of Pilatus aircraft is their versatility,” explained Mueller. “For instance, medical interiors can be designed to be modular, with certain medical equipment and features that can be configured or swapped before a mission, while the basic structure of the interior remains unchanged. In between missions, the aircraft can be converted from a medical setup to a VIP configuration (or other uses like cargo), depending on the operator’s needs. This adaptability ensures the aircraft can serve multiple purposes without the need for a full redesign, offering operators flexibility and operational cost savings. The modular approach also allows for future upgrades or adjustments to the interior based on evolving medical standards or operational requirements.”

The modular approach also allows for future upgrades or adjustments to the interior based on evolving medical standards or operational requirements

Flexibility is an angle that is also adhered to by the modification organizations, who exist to make sure that the customer gets the right interiors that are ideally suited to the patients that are being transported: “[Spectrum Aeromed has] more than 60 STCs across almost 250 different aircraft platforms and nearly 1,600 medical systems delivered worldwide,” explained Heinicke.

“If a customer’s request goes beyond our current product range, our in-house design and engineering team can customize solutions to meet very specific medical or operational needs.”

Flexibility is a watchword that many organizations adhere to, allowing for better and more efficient use of the aircraft. Explaining how interiors are initially installed and then subsequently adjusted, Kraus said: “The initial conversion is typically performed by certified specialists to ensure compliance with airworthiness standards and proper integration of systems. Once installed, flex interiors are designed for easy reconfiguration, allowing operators or crewmembers with basic training to adapt the cabin layout without requiring specialized tools or engineers. This user-friendly approach enhances operational flexibility and reduces downtime between missions.”