by Aeros Team

Utilization of air vehicles as ambulances (EMS-Emergency Medical Service) started in World War I and they were intensely used during the Korean War and the Vietnam War. The first registered aeromedical evacuation was the transfer of a British soldier with an ankle injury from Magdhaba to a gathering point near Al-Arish with the DH-4 airplane.

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This first registered EMS operation was remembered in history as it shortened the transfer that would have taken 3 days by land to just 45 minutes by air transfer. The importance of EMS was later more appreciated particularly on the battlefield and nowadays its usage has become quite popular in a wide range of services. The first aviation EMS in the civil area was registered under the title “Royal Flying Doctor Service” in 1928, in Australia. The first certified EMS modification to an aircraft by the FAA was realized in 1947.

Presently, air ambulance transportation is used both for military and civilian purposes, and only in just the U.S. alone nearly half a million EMS operations are conducted every year. The utilization of air vehicles modified with EMS equipment enables the execution of first aid, transfer of the patient to hospitals and tracking of the patient’s condition throughout the transfer process especially in emergency cases and in regions with unfavorable road transport conditions.

For the accomplishment of EMS, air vehicles must be equipped with special devices/equipment. Similar to ambulances, air vehicles with EMS also contain special medical equipment and the utilization of such systems should be enabled under flight conditions which makes EMS operation much more difficult. EMS modifications can be made to both fixed wing and rotary-wing air vehicles so that they are able to function as flying ambulances.

The design and integration steps to be applied for EMS modification have similar processes that are applicable for other aircraft modifications and both design and integration activities are subject to airworthiness and certification rules.

The air vehicles to be modified for EMS are identified according to the geographic properties and flight conditions in which they will operate while performing ambulance services. Firstly, the operational purpose should be identified. The level of medical response and the required parts and equipment should be clearly defined. The system requirements should be identified in accordance with this operational purpose. The development of the EMS system and the related equipment that will be integrated to the air vehicle shall be realized according to the system requirements.

Except for the cockpit, the internal units of the air vehicle are completely removed, and all unnecessary equipment and systems are taken out from the aircraft equipment list. Then the air vehicle is modified for medical personnel, patient systems and medical devices.

For the integration of the equipment and systems to the air vehicle, aircraft structure modification and electrical system modifications must be done.

Identification of the systems to be removed from the existing platform, structural modifications for the placement of the medical personnel, patient and medical equipment (cockpit/cabin unit and avionic compartments), layout of the EMS equipment with infrastructure and reinforcement activities required for all systems are carried out as part of the structural modifications. The structural modification activities to be conducted are fulfilled in a way to assure the flight safety of the air vehicle, staff and the patient under special conditions such as crash landing or hard landing. These special situations are defined in FAR 27.561 and the design activities should be conducted in a way to validate these criteria for the EMS equipment within the modification of the air vehicle.

The systems to be installed on the air vehicle will be powered by the electrical systems of the air vehicle and necessary data sharing is required with other avionic systems, so the specifications of the electrical buses, circuit breakers, required control panels and data communication requirements with other equipment should be identified. Modification of the lighting system is also essential so that medical personnel are able to perform the required medical response in the cabin during night or low-light conditions.

To ensure the necessary connections for power, lighting and data requirements, the wiring within the air vehicle should also be modified. Similar to the structural modification, the identification of the wiring to be removed and new wiring requirements should be made and the integrated wiring design should be made in accordance with these requirements.

In addition to the medical systems, the internal and external communication systems are modified in order to fulfill the communication requirements of the medical personnel in the air vehicle and with the medical units (hospitals) on the ground. As part of the ICS (Internal Communication System), required modifications should be made so that internal communication can be conducted between the medical staff and the flight crew. The integration of an additional radio to enable the communication of the medical personnel with the medical units on the ground about the condition of the patient is also possible.

Following the completion of modifications on the air vehicle, all systems should be verified after the modified layout and structural design, wiring installations and the integration of new equipment. Ground and flight tests are conducted for verification activities. In addition to proving the functionality of the EMS systems, these tests are executed to demonstrate that the air vehicle’s existing systems function without any performance loss following modification.

Equipment installations should neither create any negative impact over the performance of the medical equipment nor cause any changes over the functionality and performance of the existing systems of the air vehicle and the air vehicle itself.

Since EMS systems are powered by the electrical power generation sources of the air vehicle, the electrical load analysis (ELA) regarding the modification should be performed. ELA should demonstrate that the power consumption of the EMS equipment integrated to the air vehicle as part of the modification, in addition to the existing systems operating with the power of the air vehicle, does not exceed the electrical power generated in the air vehicle during all phases of flight. Moreover, a special method that would enable the pilot to cut the electrical power supplied to the EMS systems should be provided to be used during emergencies.

All modification activities over the aircraft should be conducted with consideration of total weight of the platform. Furthermore, the installation of new systems should be made in a way to allow the platform’s center of gravity to remain within the flight limits. All analyses to be conducted should be carried out by considering the number of medical personnel and patients within the air vehicle and their layout. Design activities should be executed to allow all potential operational conditions to be safe under all flight limits and durations.

It is important to demonstrate that the structural integration of all equipment installed on the air vehicle as well as the system layout within the scope of EMS are protected under challenging conditions, such as hard landings.

Ground tests which are identified for requirements as MoC-5 (Means of Compliance) are conducted after the integration of the equipment and modification of air vehicle as part of the STC (Supplemental Type Certificate) activities. The electrical power system, when all systems are functioning, is tested to verify the amount of power consumption is within limits. Additionally, operational tests regarding the scenarios for patient’s embarkation and evacuation and verification of the functionality of the EMS equipment are conducted. During flight tests, the requirements which are identified as MoC-6 are checked during the critical points of the flight to verify that the systems are preserving their structural integrity, are functioning under variety of flight conditions and the integrated operation with other air vehicle systems is functioning properly without any performance loss.

The modifications made on the air vehicle should not be dealt with irrespective of the airworthiness and flight safety concepts. Therefore, the EMS modifications are also subject to international regulations. For instance, the FAA’s regulation no AC 135-15 is applicable to EMS modifications.

Regulations of the EASA are defined under the “Annex V-Part-SPA Subpart J HEMS”. This regulation stipulates the criteria for EMS modification of the civil air vehicle. Similar to other air vehicle modification activities, those related to various engineering disciplines should be conducted as part of EMS modification activities.

The medical response is defined at two different levels in the AC135-15 regulation. These are namely the BLS (Basic Life Support) and ALS (Advanced Life Support). BLS capability contains the basic first aid and oxygen support required for the transfer of the patient, aspiration, and lighting and temperature control for the response of the medical personnel. Direct communication should be available for the medical personnel in the air vehicle and ground units for the transfer operation of the patient.

In addition to the aforementioned BLS capabilities, it is recommended that ALS should include systems/equipment that enable the medical response and support processes such as defibrillation and establishment of vascular access and equipment required for tracheal intubation, cardiac resuscitation, cardiac rhythm monitoring.

In addition to the basic first aid supplies, EMS platforms contain an oxy-acetylene welding kit, aspirator, stretcher, seating for medical personnel, electrical power supply for EMS systems, ECG device and defibrillator. Airworthy incubator systems for the transport of babies are also utilized when required. Following is the list of the equipment of a typical EMS system:

• Main Stretcher

• IV Poles

• Portative Suction Aspirator

• Portative Sphygmomanometer

• Neck Collar Set

• Reanimation Unit

• Portative Oxygen Set

• Laryngoscope Set

• Intubation Tubes

• Airways

• Balloon Valve Mask

• Injection Set

• Magill Forceps

• Diagnostic Light Pen

• Roller Bandage

• Defibrillator

• Transport Ventilator System

• Transport Incubator System

The following aspects should be verified for all equipment integrated to the air vehicle as part of the EMS modification:

• Airworthiness

• No negative impact on the systems of the air vehicle

• Compatibility with the environmental conditions and EMI/EMC conditions of the air vehicle

• No performance loss when the equipment is integrated to the air vehicle

• Compatibility with the operational scenarios

In addition to these points, the rules regulating the training of the medical personnel, maintenance services, flight guidelines and operations that need to be observed by the service provider operator are defined in AC 135-15.

All aforementioned design activities must be conducted by design offices with Part-21 approvals that shows the organizational capability of air vehicle design which is obtained from authorities such as the FAA, EASA and DGCA (Directorate General for Civil Aviation). The STC (Supplemental Type Certificate) shall be issued for the specific type of the aircraft and defined EMS architecture. After the approval of the STC by the certification authority, certified maintenance organizations with Part-145 should implement the necessary changes to the aircraft within the defined STC data.

For today, in cases where road transport is restricted or risky, EMS operations are mostly executed for the swift and safe delivery of organs to hospitals for transplantation operations and the urgent transfer of patients/casualties depending on weather conditions. The is an increasing trend, especially during disaster and emergency cases, for the utilization of air ambulance operations for the rapid transfer of casualties/organs even during secure conditions.

Currently, air ambulance services are included in the services provided by our Ministry of Health and EMS are employed effectively for the transport of casualties to modern hospitals from regions with challenging road transport conditions.

Our country is located in an active seismic region and has experienced quite massive earthquakes in the past and it is still under risk. EMS bears great importance as it is the sole method to be used for the transfer of casualties where ground transport is limited or impossible, particularly in natural disasters such as earthquakes. If companies and institutions that own private air vehicles apply modifications for the rapid transformation of their air vehicles to EMS, it will be quite useful both for their own purposes and also as a service to the Ministry of Health in emergency cases. The number and locations of the EMS platforms should be extended based on the analysis of the disaster scenarios. Also, with the rise of healthcare tourism in line with the targets of our country, and the importance of transferring patients via international flights, these factors will also influence in the need for more EMS platforms