Authors
Norimitsu Koike
Koshi Yamamoto
概要：
日本における海上空港はその立地特性上、周辺地域の救急機能から隔離しており、 航空機事故発生に伴う多数負傷者に対応できない恐れがある。そこで本研究では、 負傷者搬送シミュレーションモデルを構築し、搬送力不足から現場に留め置かれ る負傷者数を予測した。その結果、中部国際空港では多数負傷者に救急車両のみ では速やかな搬送は難しく、ヘリコプターの活用や、現場救護所にて十分な手当 てを施す必要があることを示した。
In an airplane accident, the development of rescue function in and around airport supposes to have an affair with rescue activity. ICAO(International Civil Aviation Organization) refers to prepare grid maps and gets hold of rescue function in a circle with the radius of 6 km in and around airport. 1) As Japanese new airports constructed in the offshore area by reclaiming (after this, offshore airport) are surrounded by sea, and few rescue functions are arranged in the concerned area decided by ICAO. It is necessary, therefore, to check the possibility of smooth rescue activity at offshore airport in an airplane accident, and to take measures about airport facilities such as emergency hospitals, disaster helipads, etc. The transport simulation purposes to show the injured left on the scene of an accident by insufficient transportability as the index of rescue activity. The subject in this paper is Kansai International Airport (after this, K.I.T., now using), and Chubu International Airport (after this, C.I.T., under planning).
Among airport facilities concerned with rescue activity, we take up two facilities, and propose some measures with the simulation result.
We try to show whether or not helicopter is useful to get transportability, and propose to set helipads in the offshore airport.
(b)Medical facility
We try to show the process of accommodating the injured, and provide the useful data for medical facility planning.
After injured persons rescued from the crashed airplane, they have triage (given priority) and treatment then they are transported to emergency hospitals in order of the priority. The transport means (ex. ambulance, helicopter) go to and return from hospitals until all injured are transported. For simulation model, some parameters needed about the rescue activity are such as the transport means, the emergency hospital.
The values of necessary parameters are set based on the data from the Garuda Indonesian Airplane Accident in Fukuoka Airport 1996(after this, Garuda Accident). This accident is the most recent one in Japan, and is a typical overrun accident with 107 injured.
(2)Setting some parameters
(a)Outbreak of the injured
Y=-0.0023×t^2+0.9864×t R^2=0.96 (1)
ICAO presumes that the survival rate by airplane accident as 25%, itemizing priorty1(the serious injured) is 20%, priority2 (the moderately injured) is 30%, priorty3(the slightly injured) is 50%. As ICAO doesn't refer to rescue equation, equation(2) given by modifying equation(1) adopts as rescue equation for the estimated value of the injured.
Y=( 0.0023×t^2+0.9864×t) ×S／107 (2)
According to kind of airplanes , the estimated value of the injured: S may be varied. As C.I.A. and K.I.A. have many arrival and departure of B-747, S is presumed as 125. However, when the simulation model applies to a certain airport where the number of the estimated value of the injured is different from Garuda Accident, it needs some alteration.
(b)Emergency hospitals
Fj=Sj×Jj／B (3)
(c)Ambulances
D=30.95×H R^2=0.52
(d)Necessary time for admitting the injured in hospital.
(e)Helicopter activity
①Transport route
The flight route of helicopter proposed by Mizuhashi and others is shown as the Fig.1.
②Necessary time for taking off
The necessary time for taking off is conformed to Erlang distribution of average time 24, phase 4 with significance level 95%. The sum of the value obtained by Erlang random number and 10 minutes for loading stretchers is adopted necessary time for taking off.
③Necessary time for accommodating medical staff
In an emergency hospital, the helicopter accommodates medical staff and appliances. Necessary time for these works is supposed that the sum of accommodating time of the injured in hospital and in scene obtained by the data of Practical Study. That becomes the sum of Erlang random numbers of average time 4, phase 3, and average time 3, phase 4.
④Necessary time for admitting the injured
Accommodating time of the injured is adopted just as the data of Practical Study .
⑤Necessary time for admitting in hospital and taking off
Same data of②is adopted as the result of consideration about shifting medical staff and getting medical appliances.
⑥Flight time
Flight time is supposed as equation (5),(6) with high correlation coefficient.
Outward: Y=1.19×X^0.67 R^2=0.82 (5)
Backward: Y=1.26×X^0.64 R^2=0.83 (6)
They account for the characteristic of helicopter, because the average speed increases with flight distance as the influence of landing and taking off decrease relatively. Though the cause of difference between outward and backward may come from the weather condition in the report of the Practical Study, we suppose it comes from the kind of landing space.
Case1 in Table1 shows the mean value of waiting time in completely original case(before Izumisano civil hospital moved). It is proved that the all of the injured are transported after 207 minutes when all of the injured rescued.
Case2 in the Table1 shows simulation results in case that Izumisano civil hospital moves to the point of passageway joined at land side. It shows to have some effect, the mean value of waiting time of the priority1 is under 5 minutes.
Case3 in the Table1 shows a result in case that the injured transported are only those of the priority1 and 2. After 30 minute, they are transported just when the amount of the injured reach to the transportability of an ambulance, from those results, K.I.A. may be said to have an adequate transportability .
(2)In the case of Chubu International Airport
(1)Varying allocation of the injured
Case1 in Table2 shows an allocation from equation (3) at C.I.A.. It is shown that hospitals with many beds are located far from the airport. So, simulation has been executed in some cases where the allocation has changed.
Case2 is to set emergency medical center (it is NO.0 in Table2) at the point of passageway joined at land side just like when K.I.A. opened. As the result, it is shown some improvement but the mean value of priority1 is still over 10 minutes.
Case3 is to take off the farthest hospital, the many injured are transported to the hospitals near the airport. The result is shown as the mean value and the all injured transported time decrease. In Table2,the injured allocated to some hospitals are shown as an odd number. This means that ambulance are not fill their transportability (because of their transportability sets two injured). So, we make an alteration at the allocation as shown Case4 in Table2, and has excused the simulation. The results of Case4 in Table1 shows the transport activity is more efficient and each index is improved in comparison, but the mean value of the priority1 is still over 10 minutes.
(2)Improvement transportability
An important measures derived from the simulation is to add ambulance cars. But when K.I.A. opened, no ambulance car is added around the airport. So, we consider the way of adding transportability by other means. Case5,6,7 of Table1 shows the results of using one, two, three helicopters respectively. The results of case7 shows that the mean value of the priority1 is 5 minutes, and all injured transported time is 207 minutes. As the results, helicopters become effective transport means. Therefore it is necessary to build helipads for transport at an airplane accident and construct a control system for some helicopters being active. But the other measures are necessary for the waiting injured.
Finally, we simulate in the condition of adopting the allocation of Case4 where three helicopters added. The result is shown as Case8 in Table1. The priority1 is not changed, but the priority2 decreased under 1/3 in comparison with the Case1.
(1)Regarding disaster Helipads
In some nations making use of helicopters for medical service, the airports have hovering spaces for helicopters. As K.I.A. has one helipad. C.I.A also needs to built helipads at the place close to a runway. Further more, it is expected new emergency medical system with air rescue by helicopters should be constructed as a substitute for the present system in Japan where ambulance cars are mainly introduced.
(2)Regarding an emergency medical facility
The priority1 is in danger of meeting his end within 60 minutes. Therefore the injured of priority1 have to be transported as soon as possible. But from the simulation, it becomes clear that their waiting time of ambulances is so long to them. It is necessary, therefore, to prepare enough medical treatment in the waiting time. For this purpose, an airport clinic should arranged at the ground floor to function not only in ordinary occasion but also in emergency one. the information from the simulation will be helpful in airport planning to equip with the necessary medical appliances and space.
References
1)ＩＣＡＯ; Airport Work Manual No.7(In Japanese), P32, 1980.
2)Fukuoka Fire office; The report of Garuda Indonesian Airplane Accident, 1996
3)ＩＣＡＯ; Airport Work Manual No.7(In Japanese), P60, 1980
4)Japan Conference of Traffic Science; Practical study of helicopter for emergency medical system ,1993.