Design of an Air Ambulance Aircraft for the Australian Environment

Transcription

1 49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition 4-7 January 2011, Orlando, Florida AIAA Design of an Air Ambulance Aircraft for the Australian Environment Allison L. Adorni-Braccesi 1 and Cees Bil 2 School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne, VIC 3001, AUSTRALIA Australia is a large country with the majority of its population living in capital cities on the coast line. The inland part of the county, also referred to as the Outback, is sparsely populated and not easily accessible. The Royal Flying Doctor Service (RFDS) is a national organisation providing Australia an airborne medical transport and emergency paramedic service. Currently the RFDS covers an area of 7,150,000 km 2, flying on average 65,544 km a day. Their fleet consists of about 60 aircraft, flying of 21 bases Australia wide. The performance of the aircraft that the RFDS uses are critical to the quality of their services they provide. To date, there has never been a custom build Air Ambulance, neither in Australia, or the rest of the world, a surprising fact, when it is considered that there or over 100 Aero-Medical companies operating in the USA. The aircraft currently in use are converted business or light regional aircraft that were not designed specifically for MediVac operations. These conversions are both time consuming and costly, with the last purchase and refit costing the RFDS over 8 million Australian dollars. This formed the basis of an undergraduate student design project to design an aircraft specifically for MediVac operations. The Request for Proposal was drawn up Air Ambulance Victoria whose staff also provided valuable support to the students. This paper gives a summary of the findings of that design project. T I. Introduction HE Royal Flying Doctor Service (RFDS) is an emergency and primary health care service for those living in rural, remote and regional areas of Australia. It provides health care to people who are unable to access a hospital or general practice due to the vast distances of the Outback. The service began in 1928, originally as an experiment known as the Aerial Medical Service (AMS) which was to run for a single year. This experiment was based in Cloncurry, Queensland. It was formed by Rev. John Flynn, the first Superintendent of the Australian Inland Mission (AIM), a branch of the Presbyterian Church of Australia. The first RFDS aircraft was a De Havilland DH.50 leased from the founders of what was later to become Qantas Airways. Within the first year of operations, the service flew approximately 20,000 miles in 50 flights, becoming the first comprehensive air ambulance service in the world. The RFDS fleet numbers 60 aircraft: 29 Beechcraft B200 King Air 5 Beechcraft B200C King Air 2 Cessna 208B Grand Caravan 24 Pilatus PC-12 Figure 1. Patient loading through side door. 1 Undergraduate Student, School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia, AIAA Student Member. 2 Associate Professor, School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia, AIAA Senior Member. 1 Copyright 2011 by the, Inc. All rights reserved.

2 With the operation of our aircraft across and into many remote areas and places, airstrip maintenance staff and facilities normally available at most population centres are often not available. As a result of this, to ensure the safety of our crews and aircraft, the RFDS is reliant on people in remote and isolated areas to maintain a high standard of maintenance to their airstrips. The general requirements are based on CAAP 92-1(1) Guidelines for Aeroplane Landing Areas. The airstrip is maintained by the local population and must be kept operational at all time. Before the arrival of an aircraft, the runway is checked with a motor vehicle and if necessary, prepared using a grating device towed behind a motor vehicle. The RFDS services more than 80% of Australia (7,150,000 km 2 ), an area nearly the size of the United States of America. On average per day, it attends to 750 patients, performs 100 medical evacuations, flies 65,000 km with about 200 takeoffs and landings. The RFDS operates standard aircraft that have been modified for MediVac operations. An interesting question is: what would an aircraft look like if it was designed specifically for MediVac operations as carried out by the RFDS. Would there be significant differences in design features and aircraft performance. This question formed the basis of an undergraduate student design project at RMIT University. In collaboration with the Air Ambulance Victoria and Five Rings Aerospace Pty Ltd a typical design specification was drawn up (see appendix) and given to a design team of 12 students. This paper gives a Figure 2: Typical air ambulance interior. summary of the design proposal with discussions about their specific design choices. II. Major Design Requirements Using appropriate sizing estimations a matching chart was constructed and a suitable sizing was chosen for the Air Ambulance (Figure 3). A number of constraints were considered in conjunction with the matching chart, these include: Stall requirements of maximum co-efficient of lift for different flap deployments. Take-off requirements for FAR 23. Landing requirements for FAR23. Climb rate and climb gradient requirements specified by FAR Climb rate requirements specified by FAR Climb gradient requirements specified by FAR Cruise requirements at a speed of 245 kts and an altitude of ft. The design point P was chosen to minimise the necessary power required and the surface area required. Using an estimated takeoff weight of 5693 kg, the following sizes for the Air Ambulance were found: Wing loading 1,266 N/m 2 Power loading 35.2 N/kW Wing surface area m 2 Power available 1,584 kw A. Cargo Door Possibly the most important and necessary element of a custom built Air Figure 3. Matching chart with chosen design point P. Ambulance is the cargo door, used to load the patients, and the patient loading system itself. While the current Air Ambulance aircraft have these elements fitted to their aircraft in the best way possible, designing an Air Ambulance around what is most comfortable, safest and least disruptive for the patient is 2

3 paramount to the success of the aircraft. If the patient does not have to be inclined on steep angles during loading, and does not have to change from a road stretcher to an aircraft stretcher, it will be easier for paramedics to attend to them, and in the case of spinal injuries, the less movement the better. It is from this requirement in the RFP that the basis of the aircraft is formed. Having little to no inclination of the patients means that it is best for the aircraft to be low to the ground, thus a high-wing configuration has been decided upon. This decision is supported by the fact that the RFP states that the aircraft must have Short Take-off and Landing (STOL) capabilities, as most of the rural airstrips that are used by the RFDS are not of normal length. The rear patient door for the Air Ambulance aircraft is an inward opening plug-type stressed door. The door is located in a highly loaded area of the fuselage due to the forces from the empennage, and represents a large cut-out in the fuselage so the door will be a stressed type in order to transfer the stresses to the fuselage structure. The door is an inward opening plug type for various reasons, including in-flight safety, pressurisation and structural considerations. It is hinged from the top as required and the hinges are attached to the rear bulkhead for structural reasons. Using the rear bulkhead to attach the empennage and the rear door means that it must be flat rather than the optimal cylindrical design for pressurisation leading to increased weight, but it is believed that this configuration will be lighter than the alternatives of providing a separate structure for these attachments. The dimensions of the rear door and empennage can be seen in Figure 4. B. Cabin Configurations The RFP also states that there are to be 4 specific cabin configurations for the Air Ambulance (Table 1). This is due to the fact that in the converted Air Ambulance aircraft, there is a limited amount of room to move, and therefore some aspects that the RFDS require are not able to be implemented. Therefore, it has been decided that the length and the size of the custom designed and built Air Ambulance will be a direct result of the internal configurations. The Figure 4. Patient Rear Loading Door. largest of these configurations consists of 2 stretchers, 4 passenger seats and 2 medical personnel seats and therefore the aircraft cabin must be able to adhere to this requirement. These different pieces of equipment must not only fit into the cabin, but the medical personnel seats must be able to access both patients, and the medical cabinets, in which the necessary supplies are stored. For this reason, it has been decided that these seats will operate on a rail system, ensuring that there is adequate access for the medical personnel, and that they are able to remain belted in for the duration of the flight, which ensures both their safety and the safety of the patients. Table 1. Four cabin configurations for Air Ambulance aircraft. Configuration 1 Configuration 3 2 Stretchers 1 Stretcher 1 Medical Seat 2 Medical Seats 3 Passenger Seats 1 Passenger Seat 2 Medical Cabinets 1 Neonatal Unit 1 Carry on Life Raft 2 Medical Cabinets 1 Carry on Life Raft Configuration 2 Configuration 4 1 Stretcher 1 Bariatric Stretcher 2 Medical Seats 2 Medical Seats 4 Passenger Seats 2 Passenger Seats 2 Medical Cabinets 2 Medical Cabinets 1 Carry on Life Raft 1 Carry on Life Raft 3

4 These four configurations are shown in Figure 5: (1) (2) (3) (4) Figure 5. Reconfigurable cabin layouts based on mission. 4

5 B. Aircraft Range and Altitude In order for the aircraft to service the greater parts of Australia, it must have an adequate range to reach the patients and return to their designated care facility. Although the range is specified in the RFP as 250 NM, however, after discussions with the RFDS and Air Ambulance Victoria, it was decided that a range of this size would only just service Victoria, and therefore did not have a hope of being able to reach the rural and remote areas. Due to this fact, it was decided that the Air Ambulance would be designed to a range of 1000 NM. This design requirement will ensure that all areas of Australia will be able to be reached, and the Air Ambulance will also have the possibility of becoming not only an Australian ambulance, but an ambulance that can be sold and used world-wide. The design critical mission profile is shown in Figure 6. The Air Ambulance is required to be capable of cruise at FL250, which, for the purpose of this Figure 6. Critical mission profile. design, will be simplified to an approximate altitude of 25,000ft (7620m). In addition to this cruise altitude, a second related requirement is that the Air Ambulance is to be pressurised to that of seal level up to 14,000ft (4,267m). This requirement must be met by the design team, as it ensures the safety and comfort of those travelling onboard. C. Short Take-Off and Landing It is clearly stated in the RFP that this Air Ambulance must be of Short Take-Off and Landing (STOL) capabilities. Therefore, the chosen wing configuration is a high-wing design, as the structural and aerodynamic advantages outweigh the opposing wing configurations. One of the major draws to a high-wing placement is its historical success in STOL aircraft, as well as the area advantage for high-lift devices. The fuselage is able to be placed closer to the ground with a high-wing configuration which is beneficial for the loading and unloading of cargo. This is obvious is the C-17, C-5 and C-141 designs - primarily military aircraft which all utilise a high-wing design as the loading and unloading of cargo is smoother without the need for special ground-handling gear, which can be linked to the loading and unloading of patients for the Air Ambulance Aircraft. When designing the tail of the Air Ambulance, the STOL requirements were considered, as well as the benefits of utilizing rear cargo doors without having too much of a structural disadvantage/interrupting the tail plane, a T- Tail arrangement has been chosen for this aircraft. It is believed that this configuration has the benefit of a larger ground clearance, which is imperative, given that the aircraft will be required to land on rough runways. In addition, reasons for this configuration include that it will aid the desired RFP requirement of having a rear cargo door, as well as being clear of the downwash from the wing, which is advantageous for STOL conditions. D. Aircraft Stability The design of the Undercarriage not only aids in the STOL characteristics of the aircraft, but also contributes to the aircraft s stability. As this aircraft will be transporting serious ill and injured patients, stability is of paramount concern to the design team. It is also a requirement of the RFP that the undercarriage must be able to operate from unsealed and wet / soft airstrips, and the cabin floor must remain level while on the ground, allowing for ease of loading and unloading of passengers and patients, as well as allowing the medics to easily move within the cabin to attend to the patients. Using these considerations, it was determined that a nose-wheel layout is the most suitable for this aircraft. In order to keep the aircraft close to the ground, the undercarriage is mounted to the fuselage in a blister configuration. The main advantage with this configuration being that the landing gear is shorter and therefore lighter than that required if it were mounted under the wing or engine nacelle. E. Material and Structures Considerations As this aircraft will be a fairly low performance aircraft, many of the expensive materials such as composites and titanium that are used for their high strength and low weight will be unnecessary. Therefore, the majority of this aircraft will be made from aluminium as it has a high strength, low weight, is cheap to purchase and has a low manufacturing cost. 5

6 Figure 7. V-n diagram for structural sizing. from this material. As there are several aluminium alloys available with very similar properties, careful evaluation of each alloy was employed to determine which would be the most appropriate. It was determined by the design team that the Air Ambulance will use T3 Aluminium as the main material for the aircraft. This material is best resistant to object damage and relatively easy to repair. Steel is also used in some components of the aircraft due to its high specific strength. Components which are strength critical structures such as the undercarriage, control surface tracks, fasteners (bolts), wing and tail to fuselage attachments will be machined F. Final Aircraft Design The final Air Ambulance Aircraft design can be seen in the following CAD drawings. 6

7 Table 2. Principal Aircraft and Performance Characteristics Cessna Grand Caravan Beech King Air 350 Pilatus PC-12 Mitsubishi MU-2 Beech King Air 200 RFP New Design Cruise speed (ktas) Certified Ceiling (ft) 25,000 25,000 30,000 15,000 35,000 25,000 25,000 Range Max payload ,100 1, ,200 (nm) Takeoff Distance 900 1,006 MTOW (m) Landing Distance MLW (m) Rate of Climb at sea level (mpm) Number of Engines Turbine Engine Yes Yes Yes Yes Yes Yes Yes Single pilot flight Yes Yes Yes Yes Yes Yes Yes Ramp Weight (kg) 3,985 6,849 4,760 5,273 5,711 5,720 5,693 Takeoff Weight (kg) 3,969 6,804 4,740 5,250 5,670 5,692 5,693 Landing Weight (kg) 3,856 6,804 4,500 5,001 5,670 5,692 5,693 Zero Fuel Weight N/A 5,670 4,100 4,513 4,990 (kg) Usable Fuel Capacity 1,009 1,638 1,226 1,225 1,653 1,243 2,355 (kg) Typically-Equipped 2,291 2,761 3,490 3,300 3,338 Empty Weight (kg) Useful Load (kg) 1,694 2, ,728 Full-Fuel Payload (kg) Max Payload (kg) 1,564 1,134 1, /1 1, Exterior Height (m) Exterior Length (m) Wingspan (m) Cabin height (m) N/A Cabin width (m) Cabin length (m) Baggage Capacity N/A 1.6 (m 3 ) Standard Capacity Seating 10 9 standard 11 max standard 10 max Conclusion In this paper, a custom built Air Ambulance aircraft design has been discussed. The aircraft has 2 turboprop engines (PTA-65B), mounted on the underside of the wing. There is access to the aircraft through a front pilot and passenger door, and patient access through a rear cargo door. This door is a stressed, plug type door, opening into the aircraft, and attached to the fuselage by a hinge at the top of the door. There are 4 main cabin configurations that will be used in this aircraft. The cabin can be converted in 30 minutes, and at its maximum configuration, it will be able to carry 2 paramedics, 2 neo-natal units, 2 passengers and the pilot. It is true that the RFDS can continue to work and save lives all over the country without a custom built aircraft. However, with the help of this new aircraft, and the changes that have been implemented within this design, the 7

8 RFDS will become more efficient, and will be able to provide the quality of care that is both wanted and needed all over the country. The cost of the aircraft will depend on the demand for the airframe as a utility aircraft. Appendix RFP: Design of a Dedicated Aero-Medical Fixed Wing Aircraft 1. Background 1.1 Fixed wing aero-medical aircraft provide emergency and non-urgent medical services across the country for the purposes of transferring sick and injured patients. 1.2 Fixed wing medical services include the transfer to/from hospitals of patients with a critical illness or injury. Sometimes these patients require stabilization prior to transport and/or clinical management during transport. Usually, flights consist of a pilot and a flight paramedic. On other occasions, additional doctors and paramedics will also accompany the flight paramedic. 1.3 Fixed wing aero-medical aircraft are also for the transport of specialized medical/rescue crews to assist local Ambulance and medical resources during a major incident. 1.4 The continuation of the patient s medical and nursing care during transport between the referring and receiving hospitals is essential. The aircraft becomes an extension of the hospital. 1.5 Aircraft used for fixed wing aero-medical operations are generally passenger transport aircraft that have been extensively modified to accommodate a medical interior and provisions for patient loading and unloading. In Australia, the two most common aircraft utilised as fixed wing aero-medical aircraft are the Pilatus PC-12 and Beechcraft Super King Air B200. For example, Ambulance Service New South Wales operate B200 aircraft with an interior that has been modified to accommodate two stretcher patients and three passenger seats. Each aircraft is fully furbished with a comprehensive range of up-to-date medical and nursing equipment. 2. Aircraft General Specifications 2.1 The Aircraft must meet the airworthiness standards of CASR Part 23 Normal or Commuter Category (FAR Part The Aircraft must be certified, equipped and maintained for single pilot flight under the IFR by both day and night. 2.3 The Aircraft will be multi-engined and be capable of performing at ISA + 10C at loadings per the primary cabin configuration requirements specified, with sufficient IFR fuel for 250 nautical miles plus reserves, into an out of the SLAs listed in Annex The Aircraft will be turbine powered. 2.5 The Aircraft will be equipped with an engine fire detection and extinguishing system as well as approved portable fire extinguishers mounted in the cockpit and cabin. 2.6 The Aircraft will have Short Take-Off and Landing (STOL) capability. 2.7 The Aircraft will be capable at FL250 of a normal cruise speed of at least 245 knots True Air Speed at normal cruise power settings. 2.8 The Aircraft is to have a pressurised cabin, capable of maintaining sea-level pressure to at least 14,000 feet altitude, and is to be fitted with a Cabin Pressure Controller capable of varying the cabin altitude in level flight. Back lighting of the rear altimeter is to be provided. 2.8 The Aircraft will be equipped with anti-icing and/or de-icing facilities to the standard required to meet the Aircraft Flight Manual requirements for flight into known icing conditions. 2.9 The Aircraft is to be fitted with suitable foul weather channelling around doors (and wing lockers, if applicable) to limit water entry onto stowed medical equipment during transit stops in adverse weather conditions The Aircraft will have high floatation type landing gear or equivalent, enabling operations to and from unsealed and wet / soft airstrips. 3. Primary Cabin Configurations 3.1 The Aeromedical Fitout will cater for four (4) primary cabin configurations as detailed in this section. 3.2 For Cabin Configuration 1 the cabin will be configured with: two (2) stretchers; 8

9 3.2.2 one (1) medical seat; three (3) passenger seats; and two (2) medical cabinets. 3.3 For Cabin Configuration 2 the cabin will be configured with: one (1) stretcher; two (2) medical seats; four (4) passenger seats; and two (2) medical cabinets. 3.4 For Cabin Configuration 3 the cabin will be configured with: one (1) stretcher; two (2) medical seats; one (1) provision for neonatal unit; one (1) passenger seat; and two (2) medical cabinets. 3.5 For Cabin Configuration 4 the cabin will be configured for one Bariatric patient with: one (1) bariatric patient stretcher; two (2) medical seats; two (2) passenger seats; and two (2) medical cabinets. 3.6 Cabin Configuration 4 assumes a patient in the weight range of 160kg - 240kg and specialised stretcher. The stretcher will be positioned within the cabin to allow an oversized patient to be secured. Note Cabin Configurations 1, 2 and 3 will not be required to carry a patient in excess of 160kg. 3.7 For all four cabin configurations a position will be allocated for the carry-on life-raft. 4. Secondary Roles 4.1 The Aeromedical Fitout will cater for the Secondary Roles as detailed in this section. 4.2 Secondary Roles will include Victoria Police operations involving Special Operations Group (SOG), Search and Rescue (SAR) and Major Collision Unit (MCU). 4.3 For Secondary Roles the cabin will be configured with between four (4) and eight (8) passenger seats. 4.4 For Secondary Roles the remaining cabin volume will be used for carry-on-equipment in transit cases as detailed in Annex Carry-on-equipment will be secured by cargo nets and appropriate tie-downs. 4.6 The Contractor will provide cargo nets and appropriate tie-downs for Secondary Roles. 5. Additional Configuration Related Requirements 5.1 The Aircraft will be able to be re-configured between any of the configurations in 30 minutes. This includes both primary items and support equipment such as rafts, life jackets. 5.2 The general design of the Aeromedical Fitout should aim to reduce weight wherever possible. It is an aim to be able to carry four passengers and two Neonatal cots with full fuel. 6. Stretcher Requirements 6.1 Aircraft cabin will accommodate two complete (stretcher top and base) FW 50E road ambulance stretchers arranged head to tail within the cabin with sufficient room to allow access to both stretchers from the Medical seat. Stretchers can be arranged with both stretchers on one side of the cabin or on alternate sides. The only unacceptable configuration is for the forward most stretcher to be on the same side as the medical cabinet. 6.2 The stretcher restraint mechanism will support the aircraft certification basis cabin seating loads assuming a 160 kg patient. Note: The FW 50E is designed to meet the requirements of AS4535: The stretcher restraint mechanism will be released via foot action. 6.4 In Cabin Configuration 4 the restraint will be sufficient to secure a 240 kg patient. Note the restraints for Cabin Configuration 4 are not required to be in place all the time and Cabin Configuration 4 can be retrofitted (refer reconfiguration time requirements). 6.5 Each stretcher will be capable of being off loaded or loaded into the cabin with the other stretcher remaining in place and loaded with a patient. 9

10 6.6 It is desirable for aircraft seats to remain in position while stretchers are loaded and unloaded. 6.7 Bariatric Patient Stretcher Two stretchers capable of carrying a patient weighing up to 240kg (refer Cabin Configuration 4) will be provided by the Contractor, of appropriate dimensions to suit this patient type, and with appropriate restraints Note this requirement exists even if road ambulance stretchers are to be used for all other configurations For these stretchers all of the requirements specified, excluding dimensions and weights, in the previous stretcher descriptions remain. 7. Neonatal Units 7.1 The Aircraft will be capable of carrying a neonatal unit at either stretcher position. 7.2 It is desirable that the Aircraft will be capable of carrying two (2) neonatal units at the one time. 7.3 The existing neonatal units have a mounting interface for the FW 50 stretcher top. 8. Medical Seat Requirements 8.1 Medical seats will be designed to slide along the seat rails. 8.2 There will be one medical attendant seat (the primary seat), mounted in rails adjacent to the stretcher positions, that can be slid for and aft to allow the attendant to align with both stretcher position and slide forward to access the forward medical cabinet. 8.3 This primary medical seat will be able to rotate to face forward, aft or 90 degrees to face the stretcher. (The ability to lock anywhere in the 180 rotation arc is preferred but locking in one of three (3) positions is acceptable). Locking and unlocking will be a one (1) handed operation. 8.4 If a side facing position is available then there must be sufficient space between the seat and the stretcher for the attendant. 8.5 This primary medical seat will have a four-point harness with lockable shoulder inertial restraint. Shoulder restraint unlock movement will be sufficient to allow the occupant to reach the far side of a patient on the stretcher. 8.6 The primary medical seat will have armrests that can be folded upward to align with the seat back. 8.7 There will be a secondary medical seat that can be mounted in the medical seat rails. 8.8 The secondary medical seat will be the same as the primary seat with the exception that it can be non-rotating but able to be mounted either forward or aft facing. 8.9 When not in use the secondary medical seat will be able to be removed and stowed in the baggage area or wing locker The fitment or removal of the removable seats within the aircraft will be able to be undertaken in no more than 5 minutes, without special tooling, by the Flight Crew. 9. Passenger Seat Requirements 9.1 The passenger seats will be required to be able to be mounted facing either forward or aft. 9.2 The passenger seats will have a four-point harness with lockable shoulder inertial restraint. 9.3 The passenger seats will have an aisle side folding armrest. 9.4 One passenger seat will be mounted aft facing opposite the forward medical cupboard. 9.5 The fitment or removal of the passenger seats within the aircraft will be able to be undertaken in no more than 5 minutes, without special tooling, by the Flight Crew. 10. Medical Cabinet Requirements 10.1 The aircraft will be fitted with two medical cabinets. One cabinet will be mounted directly behind the forward bulkhead on the port side. The second cabinet will be mounted in the aft cabin The forward medical equipment cabinet will face into the aisle with a rear profile to match the contour of the cabin lining The aft medical equipment cabinet will cover the port side of the rear pressure bulkhead only and have a roof and upper wall profile matching the profile of the cabin roof The rear cabinet will be open storage of 650 mm from the floor to the underside of the cabinet to provide clearance at the foot end of the aft stretcher (if required) and space for bulk cargo or luggage. This cavity is to 10

11 be enclosed with cargo netting attached to the front lower edge of the cabinet with attachment points across the floor. The remaining cabinet volume will be divided into six (3) equal size compartments with doors The medical cabinets will have stain-resistant, wipe clean surfaces Total payload of the forward cabinet will be 100kg, the cabinet will be certified to the base aircraft design loads Total payload of the aft cabinet will be 40kg All drawers and doors on the medical cabinets will have an automatic and positive catch-lock system, manually released to open drawers and doors. The drawers for drug storage will be lockable and keyed alike. 11. Aero-Medical Oxygen 11.1 The Aircraft will be fitted with a medical oxygen system capable of storing and supplying at least three thousand (3,000) litres of medical oxygen to be distributed to standard outlets mounted in the Aircraft cabin walls The design, installation and testing of the medical oxygen system shall conform to AS or higher airworthiness standards as applicable The pressure reduction system for the oxygen will be fitted at the bulk supply The medical oxygen system will provide three (3) oxygen twin-outlets for medical oxygen supply as well as two venturi suction outlets in the cabin Oxygen with twin outlets will be located in close proximity to each stretcher head and between passenger seats The oxygen fittings will be recessed where possible and positioned to preclude head-strike The oxygen fittings will be recessed where possible and sealed against the trim in such a manner as to ensure no gaps that preclude adequate cleaning exist The Aeromedical oxygen system is independent of and in addition to the Aircraft emergency oxygen system The medical oxygen distribution and oxygen control plumbing system will conform to US MIL-T-6845 or higher airworthiness standard as applicable A low pressure electric solenoid on/off valve, or manual on/off valve, will be connected to the oxygen pressure regulator and is to be controlled from both the Aeromedical Attendant s position in the cabin and the Pilot and Co-pilot positions in the cockpit Each of the outlets will be capable of delivering a flow rate of sixty (60) litres per minute at a pressure of 400Kpa An oxygen contents gauge and low-pressure oxygen alarm will be installed within the Aircraft cabin at a location easily visible to the medical seating positions A medical oxygen transfer rig is to be provided by the Contractor for the purpose of transporting medical oxygen from the bulk supply to the Aircraft. The maintenance of the rig and its components will be the responsibility of the Contractor In addition to the main Aeromedical oxygen supply, a minimum emergency supply of at least six hundred (600) litres of medical oxygen will be located within the cabin. 12. Suction Systems 12.1 The Aircraft will be fitted with adjustable high-level suction, provided by two (2) complementary systems for airborne and ground operation The Aircraft is to be fitted with a primary, under-floor-mounted, electro-mechanical suction system, and recovering fluid collection to sealed environmental and occupationally safe canisters with a minimum capacity of 350 mls The Primary suction system will be powered from the Aeromedical electrical system and be capable of being operated without the main generators for a duration of 10 minutes The design, installation and testing of the primary suction system will conform to AS as well as the CASA certification requirement Primary suction outlets will be located in close proximity to each stretcher head. 13. Cabin Environmental Systems 13.1 The Aircraft will be equipped with an air-conditioning system that covers both the cockpit and cabin areas, and is capable, during normal engine operations, of maintaining 20C. 11

12 13.2 The Aircraft cabin windows will be fitted with multi position slide blinds that are non-intrusive in the cabin area The ventilation system, used when the engines are not operating, will be capable of providing at least 20 air changes per hour. 14. Cabin Floor and Surfaces and Trim 14.1 The cabin sidewalls and headliner will be covered with a smooth, non-moisture absorbing, and washable surface The floor covering will be of a smooth, non-skid, anti-static, washable vinyl or heavy-duty rubber material, sealed against the aircraft sidewalls to window level or minimum height of 100 mm All cabin surface materials will be suitable to be wiped clean using VIRCON or equivalent cleaners For night flights, opaque washable / dry cleanable curtains or dividers will be fitted between the cockpit and cabin Roof-mounted Douglas Track, or equivalent, will be fitted from above the stretcher locations along the entire length of the stretcher Roof tracks will have purpose designed carriers and quick disconnect fittings to provide single hand operation mounting points, to a capacity of 5 kilograms, for equipment such as IV drips, patient support equipment and spot lights Four (4) recessed pockets will be located within the interior side panels of the medical cabin in close proximity to the medical attendant seats and both stretchers, with the capacity to hold 0.5kg. 15. Door and Stretcher Loading System 15.1 The Stretcher Loading Device (SLD) will be designed to provide occupationally safe and efficient loading and unloading of stretcher patients on AV Aircraft The SLD will require no more than one (1) person to deploy and assemble the device, without excessive manoeuvring and with a maximum weight of fifteen (15) kilograms to be borne by the individual The SLD will be designed to be stowed inside the cabin, in an unobtrusive position when not in use The SLD will be powered from the independent, 28 volts, Aeromedical electrical subsystem. Operation of the SLD will be taken into account when establishing the 30 minute operational capacity of the Aeromedical supply system The SLD will have a minimum safe working load capable of handling the Bariatric Patient, stretcher and loaded bridge Stretcher loading or unloading will require not more than two (2) persons, with a maximum weight of fifteen (15) kilograms to be borne by each person 15.7 Loading and unloading of stretcher patients will be achieved without excessive manoeuvring, or rotating the patient more than ten (10) degrees in roll, or eight (8) degrees in pitch, relative to the floor of the Aircraft The stretcher loading device will be designed to ensure that clinical treatment of the patient can continue during loading or unloading The Aircraft is to be fitted with a large rear access door (cargo door) hinged at the top, measuring a minimum of 1.24m in width x 1.32m in height The cargo door will be mechanically operated/assisted to avoid manual handling of the door The Aircraft will be fitted with a cabin/air stair door with a second door support cable, which may be incorporated into the rear cargo door, hinged at the bottom, and incorporate integral step and handrail assemblies which automatically extends and retracts as the door is opened and closed If the cabin air stair door is fitted to the cargo door the air stair door may be operated manually A means of boarding and exiting the Aircraft with the cargo door open will be provided The SLD will be able to be operated manually in the event of its power system failing The cargo door will be able to operated manually in the event of its power system failing. 16. Additional Stowage 16.1 Provision will be made for dedicated watertight baggage and cargo storage outside of the cabin area and be of a design and dimensions that ensure no interference with patient and the SLD The aircraft will include a visual warning system for unlocked wing lockers to be located in the aircraft cockpit. 12

13 16.3 Provision will be made for the carriage and stowage of passenger / patient cabin baggage to a limit of five (5) kilograms of soft-bag luggage per passenger The approved and required cargo restraining nets for the Aircraft, are to be carried on all flights and suitably stowed when not in use. Acknowledgments The authors would like to acknowledge the contributions of the team members to this design project. Also, the input of several people, who have been key to the considerations and decision making process throughout the year, are acknowledged. Thanks to the academic staff at the School of Aerospace, Mechanical and Manufacturing Engineering at RMIT University. Sincere thanks must also be extended to Air Ambulance Victoria, and in particular Mr. Shane Foster, to Mr. Michael Rogers, to Mr. Paul Harrison and Mr. Szymon Koronczewski from the Royal Flying Doctor Service, to Mr. Davis Jedynak and Ms. Caz Kemister from the National Transport Service, and to Mr. Glenn Secomb, Chief Engineer at Jet City Engineering, for their endless patience and for sharing their wealth of knowledge with us. A special thanks also to Mr Greg Hanlon of Five Ring Aerospace Pty Ltd who proposed the project initially. References 1 RFDS. Facts and Figures. Royal Flying Doctor Service. [Online] Figures/. 2. Our Aircraft. Royal Flying Doctor Service. [Online] Association of Air Medical Services. Fixed Wing Services. Association of Air Medical Services. [Online] W_Members. 4 Cessna. Cessna Caravan. Cessna. [Online] Beechcraft Online. King Air 350 Beechcraft. Beechcraft Online. [Online] Airliners Online. King Air 350. Airliners Online. [Online] Jane's All the World's Aircraft. Jane's All The World's Aircraft London : Paulton House, Beechcraft Online. King Air 200 Beechcraft. Beechcraft Online. [Online] Airliners Online. King Air 200. Airliners Online. [Online] RFDS. Discussions with RFDS. Melbourne : s.n., 7th May Airstrip Information. Royal Flying Doctor Service. [Online] pdf. 12 Aviation Weekly. FAA Cautions MU2 Operators While Continuing Safety Review. Aviation Weekly. [Online] &headline=faa%20cautions%20mu2%20operators%20while%20continuing%20safety%20review. 13 Roskam, J. Airplane Design: Part 1: Preliminary Sizing of Airplanes. Kansas : Roskam Aviation and Engineering Corporation, RMIT University. RFP Aero Ambulance Aircraft. Melbourne, Victoria, Australia : RMIT University, Aircraft General Specifications, Section McGraw-Hill. Short Take-Off/Landing Distance (STOL. An Illustrated Dictionary of Aviation. [Online] [Cited: 11 March 2010.] 16 Anderson, J.D Jr. Introduction to Flight. 5th Edition. New York : McGraw-Hill, Roskam, J. Airplane Design Part 3: Preliminary Sizing of Airplanes. Kansas : Roskam Aviation and Engineering Corporation, Airplane Design Part 5: Preliminary Sizing of Airplanes. Kansas : Roskam Aviation and Engineering Corporation, Raymer, D. Aircraft Design: A Conceptual Approach. s.l. : Renton, Torenbeek, E. Synthesis of Subsonic Airplane Design. Delft : Delft University Press, AVweb. High Wing or Low Wing? AVweb. [Online] IA State. Airfoil Usage. IA State. [Online] Roskam, J. Airplane Design Part 2: Preliminary Sizing of Airplanes. Kansas : Roskam Aviation and Engineering Corporation, Roskam, J. and Lan, C. Airplane Aerodymanics and Peformance. Lawrence, Kansas, USA : DAR Corpotration, Mileskin, N. AERO2359 Introduction to Aerospace Structures. AERO2359 Class Notes. Melbourne : RMIT University,

14 26 Niu, M.C.Y. Airframe Structural Desing: Practical Design Information and Data on Aircraft Structures. 3rd Edition. s.l. : Commilit Press, Farrar, D.J. The Design of Compression Structures for Minimum Weight. s.l. : Royal Aeronautical Society, Catchpole, E.J. The Design of Compression Structures For Minimum Weight. s.l. : Royal Aeronautical Society, ASM Aerospace Specification Metals Inc. Aluminium 2024-T3. ASM Aerospace Specification Metals Inc. [Online] matweb.com, Niu, Michael C. Y. Airframe Structural Design: Practical Design Information and Data on Aircraft Structures Absolute Astronomy. T-Tail. Absolute Astronomy. [Online] RMIT University. Lateral & Directional Stability and Control. AERO2225: Fundamentals of Aerodynamics [PDF File]. Melbourne RMIT University : s.n., Anything-RC. Stability and Control. Anythign-RC.com. [Online] May Roskam, J. Airplane Design Part 6: Preliminary Sizing of Aircraft. Kansas : Roskam Aviation and Engineering Corporation, RMIT. Stability & Control. AERO2225 Fundamentals of Aerodynamics. [PDF file]. Melbourne : s.n., Roskam, J. Airplane Design Part 4: Preliminary Sizing of Airplanes. Kansas : Roskam Aviation and Engineering Corporation, Mason, S.T. Landing Gear Integration in Aircraft Conceptual Design Citroen. Citroen Cars. Citroen. [Online] Rolls Royce. The Jet Engine. Rolls Royce. [Online] FAA. Regulatory and Guidance Library - Pratt and Whitney. FAA. [Online] ev24.pdf. 41 Flickr. Yakovlev Yak-40. Flickr. [Online] Ferno Australia. Ambulance Strecthers and Accessories. Ferno Australia. [Online] Flight Structures Ltd. Flight Structures Products. Flight Structures Ltd. [Online] NSW Goverment. NSW Department of Commerce Request for Tender. NSW Department of Commerce. [Online] 45 CPR Savers. Oxygen Supplies. CPR Savers and First Aid Suppliers. [Online] JAA atpl. Aircraft Knowledge 1 - Airframes and Systems. Shoreham, England : Transair (UK) Ltd, Garrent, D.F. Aircraft Systems and Components. Engelwood, CO, USA : Jeppesen Sanderson, Aviation Glossary. Continuos Flow Oxygen Systems. [Online] Diluter Demand Oxygen System. [Online] Republic of Singapore Airforce. Fuel Systems. AERO2355: Aircraft Mechanical Syetems. Melbourne : RMIT University, National Transport Safety Board. Fuel System. NTSB.gov. [Online] October Concorde Battery Corporation. The RG-380E/46 Aircraft Battery. ConcordeBattery.com. [Online] Design and Fitting Oxygen Systems: Non Required Gaseous Equiptment. Civil Aviation Safety Authority. Melbourne : s.n., May FAA. FAA Regulations. FAA. [Online] Pro Line 21 Integrated Avionics. Pro Line 21 Integrated Avionics System Information. Pro Line 21 Integrated Avionics. [Online] Rockwell Avionics. Rockwell Avionic Suites. Rockwell Avionics. [Online] Honeywell Avionics. Honeywell Avionics Systems. Honeywell Avionics. [Online] C.O, Julio. Material Selection for Aeronautical Structural Application. New York : s.n., Lombardo, D.A. Aircraft Systems. New York, USA : McGraw-Hill,