航空機事故における傷病者搬送シミュレーション

(小池則満さん、neweml 2922より, 980514)


Transport simulation of the injured by an airplane accident at offshore airport

Nagoya Institute of Technology
Dept. of Civil Engineering

Authors
Norimitsu Koike
Koshi Yamamoto



Contents

Abstract     □Abstract in Japanese
1.Introduction
2.Model Building of Transport Simulation of the Injured
3.The Results of Transport Simulation
4.Take Measures for Chubu International Airport
5. Proposals for Offshore Airport Planning
6.Conclusions and Remarks
Referenes


Abstract

The offshore airport in Japan is far from surrounding rescue functions. Therefore, we have constructed a transport simulation model to check the possibility of smooth rescue activity, when an airplane accident happens. As the results, show it becomes clear that Chubu International Airport is in danger of insufficient transportability. We propose how to decide simulation model shows the number of injured left and waiting time at the scene and around the offshore airport. These will be useful data for planning to equip such airports with the necessary medical appliance and space.


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。


1.Introduction

(1)Background

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.

(a)Disaster helipads

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.


2.Model Building of Transport Simulation of the Injured

(1) Transport activity in an airplane accident

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

The relation between t (time passage after accident happened) and Y (the sum of the injured transported) is supposed by quadratic equation (1) with high correlation coefficient.

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

As the result of hearing survey to Fukuoka Fire Office about the allocation of the injured to emergency hospitals in Garuda Accident, it becomes clear that many injured person were principally admitted to hospitals with many beds. As the result, the injured are allocated to emergency hospitals in a circle with the radius of 10 km from the foot of the bridge connecting offshore airport to land area, according to the number of beds in order of the distance.

Fj=Sj×Jj/B (3)

Fj; the injured allocation to hospital j
S; the estimated value of the injured
Jj; the number of beds in hospital j
B; the sum of the beds in all emergency hospitals
j ; hospital number

(c)Ambulances

The relation between the time required and the distance of emergency cars covered in Garuda accident can be supposed as equation (4), which is valid within the limits of 15km from airports. As the results, an ambulance speed sets at 31km/h.

D=30.95×H R^2=0.52

D: the distance(km)
H: the time required(hours)

(d)Necessary time for admitting the injured in hospital.

When the transport means arrives at an emergency hospital, the injured are handed to medical staff, and admitted. The necessary time for this process is conformed to Erlang distribution of average time 17, phase 2 with significance level 95%.

(e)Helicopter activity

In Japan, helicopters have never been used for transport means in an airplane accident. So, the practical study of helicopter for emergency medical system (after this, the Practical Study) applies to helicopters data.

@Transport route

The flight route of helicopter proposed by Mizuhashi and others is shown as the Fig.1.

ANecessary 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.

BNecessary 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.

CNecessary time for admitting the injured

Accommodating time of the injured is adopted just as the data of Practical Study .

DNecessary time for admitting in hospital and taking off

Same data ofAis adopted as the result of consideration about shifting medical staff and getting medical appliances.

EFlight 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.


3. The Results of Transport Simulation

(1) In the case of Kansai International Airport

We apply the simulation model to K.I.A, and estimate the rescue activity. The results are showed as table1.

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

Case1 in Table 1 shows the results of C.I.A. . Many injured are left in the scene, and all the priority3 can not be transported because of insufficiency of transportability. This means that, the priority3 have to be transported by microbuses and others. It is necessary to take measures for the priority1,2, because the mean value of the priority1 waiting is over 10 minutes.


4.Take Measures for Chubu International Airport

In this section, simulation is executed changing some condition to take measures against insufficiency of transportability in C.I.A..

(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.


5. Proposals for Offshore Airport Planning

In this section, some proposals are made about airport facility planning and medical planning.

(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.


6.Conclusions and Remarks

This paper has proposed transport simulation of the injured by an airplane accident. The transport simulation model can be applied even to another airports by giving necessary parameters, and make it possible to provide the useful data for taking measures to an airplane accident in a offshore airport. As the results of the simulation, we propose a disaster helipads and some date for emergency medical planning.


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.

5)Y.Mizuohashi and others, The useful method of helicopters in an airplane accident at Kansai International Airport, Japan Society for the study of Air Rescue,1996.


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