THE IMPACT OF SEAT REDESIGN IN CHANGING THE AIRCRAFT BOARDING STRATEGY

Abstract

Before an aircraft could fly again, it is absolutely necessary to complete a series of tasks, involving: * Aircraft taxiing into its parking position * Passengers and crew disebarking * Cleaning of the cabin * Baggage unloading and transportation * Aircraft inspection and the check routine based on The Standard Operating Procedures Manual * Refueling of the airplane * Catering Service * Next flight baggage loading * Boarding of the passengers * Taxiing manoeuvre in order to access the take-off runway As the numerous studies say, the passengers boarding is the main factor that directly influences the turn-around time of an aircraft. The mathematical model used by me is an ordinary differential equation model, also known as ODE. ... where: v =u'th passenger's speed V =optimal speed Axu (u > 1) =length between passengers (the u'th passenger and (u-l)'th passenger) a¾ = length between the passenger and the seat Av (u > 1) = the speed difference between consecutive passengers pu_j = the possibility that the (u-1) to be interrupted Given the fact that T.Q. Tang, H.J. Huang, H.Y. Shang in A new pedestrian-following model for aircraft boarding and numerical tests didn't take into account the fact that each passengers has individual properties, we can reduce p" ,V as it follows: ... where t1 = the time when the passenger arrives at the gate T =the time for checking the passenger's ticket t 2 =the time for reaching the seat T =the time to place the lugggae in place ... T = time to put in place the baggage Tf =additional time, caused by delays The model, according to Shang, Huang and Tang, described in their book [4], could reproduce each behavior of passengers, but it cannot be used to illustrate the impact of the passenger's individual properties on each passenger's movement [4]. [...]the same authors develop a model that could consider and take into account the passenger's properties: a, \u, ?,u = the parameters that determine each person individual properties; At the same time, according to Jia, Xie and Qiang, in [5], the time luggage has the following form: ... l = the number of baggages 4 =the number of baggage of the u'th person ... [...]an important factor that should be taken in consideration is the behavior of passengers in groups.

Headnote

Abstract: The aerospace industry and its accelerated development leads to new strategies that the airline companies must take into account to deal with the large number ofpassengers that pass through the airport daily. This paper addresses a current concern regarding aircraft passenger boarding time. Due to economical, social, operational or time reasons, both airports and airlines have interests in decreasing passenger boarding time. The boarding efficiency has been studied over the years and several reports have appeared in the literature. The aim of this paper is to propose a new approach of boarding which is closely related to a new redesigned concept of low-cost aircraft seats.

Key words: seat, aircraft, cabin, boarding, strategy, redesign.

(ProQuest: ... denotes formulae omitted.)

1. BRIEF INTRODUCTION IN BOARDIND STRATEGY

Nowadays, the aerospace industry is passing through a accelerated development stage made possible by globalisation and it highly increased competition. The increase of air transportation brings with it not only the pleasant aspects, but also un unpleasant side: traffic problems, including in air traffic congestion, flight delays or loss of luggage.

This aggressive competition of low-cost airlines are effecting the airport strategies, which is recently based on the concept of fast boarding and boarding efficiency.

An important aspect of this topic is that the delay of an aircraft could have repercussions on its entire operation cycle. As it is known, in low-cost aircraft industry, is highlighted the fact that the turnaround time is extremely low. For example, in case of Ryanair company, the turnaround for short-haul flights is less than 25 minutes. During this period, the planning team is mobilised to get the aircraft set up for the next take off for a new flight.

Before an aircraft could fly again, it is absolutely necessary to complete a series of tasks, involving:

* Aircraft taxiing into its parking position

* Passengers and crew disebarking

* Cleaning of the cabin

* Baggage unloading and transportation

* Aircraft inspection and the check routine based on The Standard Operating Procedures Manual

* Refueling of the airplane

* Catering Service

* Next flight baggage loading

* Boarding of the passengers

* Taxiing manoeuvre in order to access the take-off runway

As the numerous studies say, the passengers boarding is the main factor that directly influences the turn-around time of an aircraft. From this point of view, the use of new boarding methods could lead to saving both time and money. An relevant aspect remains the interferences between passengers. The fact that passengers have to wait for each other during the boarding process is time consuming and leads to slowing down the entire process. Researchers as Bazargan, Villalobos, Hogg or Mulé have been studied the impact of interferences and have been distinguished the interferences in two main problems: aisle and seat interferences.

2. LITERATURE REVIEW OF BOARDING STRATEGIES

Many researchers have extensively studied the problem of passengers boarding. In A study of airline boarding problem, made in 2008, McFadden proves that reducing the turnaround time of an aircraft with just one minute, it would lead to a 30$ savings for each flight. In other words, for a major airline with 5000 flights per day, the total amount of saved money would exceed the amount of 50 million dollars [3].

The boarding time in terms of aeronautics "starts when the first passenger enters the plane and ends when the last passenger is seated in his assigned seat" [2], according to Beuselinck and Landeghem.

Given the fact that the boarding problem is an issue that can be studied from several points of view, we will only address the issue of boarding the aircraft Fokker 100. The airplane is a medium-sized aircraft, whose spacious cabin measures approximately 2.9 meters wide and 2 meters high and can accommodate up to 109 passengers in five seating configurations. The access doors in the cabin, each measuring 1.92 meters high and 0.86 meters wide, according to the following figures, together with the integrated stairs facilitates a maximum operating flexibility.

This paper is based on the study of this configuration of seating, a specific setting for low cost aircraft given the fact that for long-haul flights, with a significantly larger number of seats, the boarding procedure is certainly not a time critical action. The study will be conducted only for economy class, since the business class and the passengers with special needs don't impact the decision regarding the optimum boarding technique [2].

Studies led by researchers as Sapir, Bachmat and Berend in the year of 2007 or by Frette and Hemmer in 2012 tried to find the best solution for decreasing the time of boarding.

The scientific literature, in order to explore the boarding behavior, presents three models:

* randomly

* by group

* by seat.

The first category, randomly, has not a particular strategy, passengers starting the boarding process individual immediately after the gate agent would allow the procedure.

The second possibility, by group grant the boarding of numerous passengers simultaneously. This boarding strategy could be divided into smaller classification, among which the most important are: by block and by row strategy. The most common method of boarding is back-to-front, in which passengers who have seats in the back of the plane will board earliest in order, preceded by the those who have seats in the middle of the plane, the last ones being the ones from the front of the aircraft. We are talking about a block strategy given the fact that the passengers are divided into three groups.

The third category, by seat, is the category that drew my attention the most and on which I did the most advanced research.

3. MATHEMATICAL MODEL

On the literature, there are several mathematical models that could simulate the time consumption according to the boarding method chosen, in order to compare the performance results and find the most suitable boarding strategy. The mathematical model used by me is an ordinary differential equation model, also known as ODE.

...

where:

v =u'th passenger's speed

V =optimal speed

Axu (u > 1) =length between passengers (the u'th passenger and (u-l)'th passenger)

a¾ = length between the passenger and the seat

Av (u > 1) = the speed difference between consecutive passengers

pu_j = the possibility that the (u-1) to be interrupted

Given the fact that T.Q. Tang, H.J. Huang, H.Y. Shang in A new pedestrian-following model for aircraft boarding and numerical tests didn't take into account the fact that each passengers has individual properties, we can reduce p" ,V as it follows:

...

where

t1 = the time when the passenger arrives at the gate

T =the time for checking the passenger's ticket

t 2 =the time for reaching the seat

T =the time to place the lugggae in place

...

T = time to put in place the baggage

Tf =additional time, caused by delays

The model, according to Shang, Huang and Tang, described in their book [4], could reproduce each behavior of passengers, but it cannot be used to illustrate the impact of the passenger's individual properties on each passenger's movement [4]. Thus, the same authors develop a model that could consider and take into account the passenger's properties:

a, \u, ?,u = the parameters that determine each person individual properties;

At the same time, according to Jia, Xie and Qiang, in [5], the time luggage has the following form:

...

l = the number of baggages

4 =the number of baggage of the u'th person

...

Thus, an important factor that should be taken in consideration is the behavior of passengers in groups. We assume that the number of baggages per group is equal to k. When k < 3, the last passenger to sit will put the luggage in place. So, t? could be defined as:

...

when k > 3, it means that the luggages will be placed in at least one rack:

...

Based on the assumption above, we have the certitude that Tff'c' in a group behavior would be equal to 0, so it's necessary the study of time conflict between passengers which are not belonging to any group. We define:

...

where M= number of seat conflicts. Other set parameters are:

...

4.NUMERICAL TESTS AND RESULTS

The proposed model described above was used to find the best boarding process. The initial assumptions were:

* distance between two passengers are 0.2 m

* The initial speed, calculated with the above formula, leads to:

...

* The size of groups is between 2 and 6 passengers

The boarding strategies taken into account were: Back-to-front, Random, Sorted-Boarding-Groups and Windows-Middle-Aisle.

The results shows the following fact:

Table 1 estimates the boarding time for each passenger. It is an extremely important indicator, given that a shorter time on the aisle implies an unblocked road for other passengers. As can be seen from the table, the WMA method is the most optimal, while the methods B2F, Random and SBG involve waiting on the corridor.

Table 2 display the typical number of interferences during the embarkation process. It is noted that the WMA method has 0 interference, because the strategy guarantees that passengers who are on the same line (A, B, C, D, E, F) must board one after the other, from the last place to the first, which does not involve interferences of some kind.

Figure 7 shows the sensitivity of each method of boarding passengers with luggage. It is observed that the embarking time grows linearly with the percentage of traveler with luggage. The lowest performance is in the case of B2F, due to the corridor interference and the long storage time of the luggage.

Figure 8 shows the sensitivity of the 4 techniques to the percentage of travelers traveling in groups.

In figure 9, the graph shows a correlation between the time of arrival and that of boarding. In all cases, the embarking time expand with the arrival time, but at different rates.

5.AIRCRAFT CABIN DESIGN

An important step in creating a new seat concept is the design of the interior of the aircraft. This process was performed with the help of the Maya software. The program is a 3D computer graphics application, developed by Autodesk, Inc. The application is used to generate assets for game, television development and architecture. The virtual space used has a node graph architecture, defining a virtual workspace called scenes to edit and work for a particular project.

For the design of the aircraft interior, the first step in Maya was to import an image of the real cabin with a supporting role, so that the virtual modeled cabin looks as similar as the real one.

To create the fuselage, a polygon cylinder is used, divided into 40 subdivisions (axis)(1 subdivision height).

For designing the windows, we will also use a cubetype polygon on which we will apply the bevel function of Edit Mesh and working on the offset we will bring the window shape to the closest to the real one.

The next step is to cut the upper part of the fuselage and create the ceiling. This stage is also performed using NURBS primitives.

In order to achieve a better similitude with the reality, elements such the floor will be designed. To delimit the rows A,B,C, the aisle and the rows D,E,F, the floor is divided into 3 parts (figure 13). The same principles will also be used to design the hand luggage compartments.

6.CONCLUSIONS

The main purpose of this paper was the research on the optimal solution of boarding in the aircraft. This is the aim of this paper because the new design principle of the aircraft seat is closely related to the concept of embarking. To be more explicit, the new system proposed by me envisages sliding the two rows of chairs near the aisle behind the middle rows.

This system is closely related to the boarding strategy, the concept proposed by me aiming the entry into the aircraft of the passengers who have seats near the window, back to front, followed by the middle rows. The last step is the sliding of the seats next to the aisle by the stewardesses and the embarking of the passengers occupying these positions.

Both literature review and numerical simulation show that this concept is the most reliable (WMA). One of the aims of this paper was to demonstrate that this mode of boarding is the best, to come as an argument for choosing the system of sliding seats.

Sidebar

Author:

Eng. Simona BLÎNDU, Master student, University Politehnica of Bucharest, Faculty of Aerospace Engineering, Department of Engineering Graphics and Industrial Design; E-mail: [email protected]

References

REFERENCES

[1] Horstmeier, T.H.W., de Haan, F. (2001). Influence of ground handling on turn round time of new large aircraft. Aircraft Engineering and Aerospace Technology, Vol. 3, No. 71, pp. 266-270.

[2] van Landeghem, H., Beuselinck, A. (2002). Reducing passenger boarding time in airplanes; A simulation based approach. European Journal of Operational Research, 142(2), pp. 294-308.

[3] Nyquist, D.C., McFadden, K.L. (2008). A study of the airline boarding problem, Journal of Air Transport Management, 14 (4), pp. 197-204.

[4] Tang, T.Q., Huang, H.J., Shang, H.Y. (2012). A new pedestrian-following model for aircraft boarding and numerical tests, Nonlinear Dynam., No. 67, pp. 437443.

[5] Qiang, S.J., Jia, B., Xie, D.F. (2014). Reducing airplane boarding time by accounting forpassengers' individual properties: a simulation based on cellular automaton. J. Air Transport. Manag. No. 40, pp. 4247.