Journal of Power and Energy Engineering, 2015, 3, 449-452
Published Online April 2015 in SciRes. http://www.scirp.org/journal/jpee
http://dx.doi.org/10.4236/jpee.2015.34061
How to cite this paper: Meric, O.S. (2015) Optimum Arrival Routes for Flight Efficiency. Journal of Power and Energy
Engineering, 3, 449-452. http://dx.doi.org/10.4236/jpee.2015.34061
Optimum Arrival Routes for Flight Efficiency
Ozlem Sahin Meric
Faculty of Aeronautics and Astronautics, Eskisehir, Turkey
Received January 2015
Abstract
With the development of aircraft equipment, conventional navigation is the shift from perfor-
mance based navigation (PBN). As is known, conventional navigation is based on ground-based
navigation aids; however, PBN is based on aircraft avionics and performance. In this paper, a new
method called Point Merge System (PMS) considered as one of PBN procedures will be introduced.
PMS has many benefits related to fuel savings and emission reductions by implementing Conti-
nuous Descent Approaches (CDAs). A new PMS standard arrival route (STAR) model will be de-
signed in radar simulation and it will be suggested.
Keywords
Performance Based Navigation, Area Navigation, Required Navigation Performance, Point Merge
System, Efficiency
1. Introduction
Open loop radar vectors (tactical vectoring) included heading instructions are a common used method for merg-
ing and handling arrival traffic flows. This method is efficient and flexible but in the high traffic density areas,
the controller should give rapid decisions for each aircraft in a critical time window. Therefore, controller’s
workload and frequency occupancy time are increased. Also it is difficult to provide optimum flight profiles and
to control traffic dispersion [1]. Moreover, standard arrival routes (STARs) based on conventional procedures
could be used for handling arrival traffic. Aircraft should follow a route which is described by ground naviga-
tional aid. Due to stay dependent on ground, it limits providing more direct routing.
With the development of satellite based technology and aircraft equipment, conventional flight procedures are
shift from performance based navigation (PBN). As is known, conventional procedures are based on ground-
based navigation aids; however, PBN is based on aircraft avionics and performance. PBN consists of Area Na-
vigation (RNAV) and Required Navigation Performance (RNP) specifications. RNAV is defined as “a method
of navigation which permits aircraft operation on any desired flight path within the coverage of station-refer-
enced navigation aids or within the limits of the capability of self contained aids, or a combination of these”
(ICAO Annex 11, 2001) [2]. RNP is similar but it enables alerting and monitoring system on board namely it is
the key difference between RNAV and RNP [3] [4]. More flexible arrival and approach procedures which allow
the efficient use of airspace could be designed by using RNAV route structure. In order to maximize capacity,
sometimes, RNAV routes could be combined with conventional procedures. In that case, controller can begin to
use heading instructions. Today, instead of conventional procedures, RNAV procedures, which provide effective

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and efficient use of TMA, are preferred to be used for handling and sequencing arrival traffic operations.
A new method called point merge system (PMS) is based on RNAV route structure. PMS intends merging ar-
rival traffic flows on a point. And also it provides path stretching or shortening by using available predefined
legs.
PMS doesn’t need any heading instructions. Traffic follows a standard arrival route which enables continuous
descent approaches (CDAs) [5]. CDA is defined as a method that the aircraft intercepts glide path from optimal
vertical profile down to touchdown with engines operating at low thrust power [6]. The most common benefits
of CDA procedures are reducing aircraft noise, fuel burn and emissions [7]. Reduction in frequency occupancy
time and workload, also by enabling CDA, reduction in fuel consumption and consequently reduction in emis-
sions are the expected benefits of PMS procedure [5]. In the following part below, PMS and CDA will be re-
viewed in terms of fuel savings and emissions.
Clarke et al. (2004) made a study related to CDA procedures. It was tested by simulations that in Louisville
International Airport indicated 400 to 500 lb (181 - 227 kg) of lower fuel consumption during approach [8].
Ivanescu et al., assessed the performance of PMS and compared with vectoring in fast time simulator. In that
study, 20% reduction in workload, approximately 30% reduction in number of controller instructions and 170
kg ± 14 kg reduction in fuel burn were obtained [9].
Another study reporting fuel savings due to CDA was made by Turgut et al. (2010). Conventional and CDA
procedures were compared by using real flight data for B757 and more than 40 kg fuel and 2 minutes time sav-
ings were reported for CDA procedures [6]. Robinson (2010) studied on different CDA scenarios and the results
of simulation indicated 50 kg - 150 kg fuel savings at medium or low traffic density [10].
PMS has been applied in Oslo in 2011. The results for Oslo present that PMS has more advantages over vec-
toring such as providing more efficient and predictable way, reducing workload, improving safety and minimiz-
ing environmental impacts by allowing CDA. The results indicate 300 kg reduction per flight in CO2 emissions
[11].
At Ahmadabad Airport in India, CDA procedures have been implemented. Fuel savings about 1164 tonnes
and 3678 tonnes CO2 emission reduction annually were reported. Moreover, another study related to CDA was
performed in Praque. It is addressed that 65 - 96 kg fuel savings and 200 - 300 kg CO2 reduction per flight could
be estimated and it corresponds to 1400 tons fuel savings and 4600 tons CO2 reductions annually [12].
The previous studies given above stress a significant reduction in fuel consumption and in CO2 emissions by
implementing PMS CDA procedures in TMA. In this study, PMS STAR model proposal is recommended for
both Istanbul Ataturk International Airport (LTBA) and Sabiha Gokcen Airport (LTFJ).
2. Point Merge System (PMS)
PMS is a sequencing method which is based on RNAV route and it is used in transition or initial approach pro-
cedure or a portion thereof. PMS could be defined as a RNAV STAR. In other words PMS could be introduced
as a method handling arrival traffic flows without heading instructions [1].
A single point and predefined legs are the elements of PMS. This method aims at integrating arrival traffic
flows on a single point called merge point. Before merge point, by using predefined legs—called sequencing
legs—collecting arrival traffic from different directions could be achieved (Figure 1). These legs could be
placed in the same distance from the merge point (eqidistant) and traffic remain on the same distance to merge
point during flight on these legs (isodistant) [5].
While operating PMS procedure, aircraft remain on sequencing legs until controllers give a “direct to” in-
struction to the merge point. After leaving the leg, aircraft might begin descending and controller use speed con-
trol instructions in order to provide in trail separation. By using PMS STAR procedures, descent profiles could
be optimized by implementing CDA.
3. A PMS STAR Model Proposal
International Istanbul Ataturk Airport (LTBA) and Sabiha Gokcen Airport (LTFJ) are in Istanbul terminal con-
trol area (TMA) and are close each other. RNAV STAR has been implemented for handling and managing ar-
rival traffic flows. For landing, 05/23 and 06/24 runway configuration is usually used for LTBA and LTFJ, re-
spectively.
In this study, different entry points to Istanbul TMA located separately for collecting arrival traffic and called

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ENT × (i.e. ENT 1, ENT 2, …). Merge points and sequencing legs are located in an appropriate point which al-
low intercepting ILS course to related runways by implementing CDA procedures. Merge points are called Tx.
T2 and T3 are used for LTBA and LTFJ, respectively. However T1 is used for both LTBA and LTFJ. T4 is the
common point which is to be followed after PMS procedures. T1 and T2 is located unsymmetrically configura-
tion so as to prevent nose to nose situation on T4. PMS procedures which include T1 and T2 is an example of
parallel combination of a PMS. Another is the serial combination and in the recommended PMS STAR model, it
could be seen at the north region of TMA. T merge point could be introduced as a feeder waypoint which helps
collecting high traffic flows to PMS procedure included T1. In order to meet high traffic demand, the number of
sequencing legs could be increased or multiple combination of PMS could be used. As mentioned above, in this
study for LTBA serial and parallel combination of PMS is preferred in design instead of increasing number of
sequencing legs.
Using PMS STAR, traffic are delayed on sequencing legs instead of holding on a point or navigational aids.
After reaching at the end of the procedure, traffic could turn to merge point automatically and also starts des-
cending. Initial waypoints for joining the PMS procedure are presented orange unfilled points, however, the last
waypoints of procedures are illustrated in filled orange. Moreover sequencing legs and the links of ATS arrival
routes are showed in blue (Figure 2).
Figure 1. PMS route structure [5].
Figure 2. A proposed PMS STAR model for LTBA and LTFJ.

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452
4. Conclusion
PMS, which is based on RNAV, is used as a method for sequencing and integrating arrival traffic and aims to
increase safety, flight efficiency and predictability. PMS procedures allow aircraft to follow more direct routings
which cause a reduction in flight time and distance. Also, PMS allows CDA procedures which help to optimize
the descent profiles. Implementing CDA, traffic proposes to descent with low drag and low thrust, and also keep
higher altitude at longer time as compared with conventional procedures. As a result, it minimizes the environ-
mental impacts such as a reduction in fuel consumption and consequently CO2 emissions. In this study, a PMS
STAR model included different design combinations of PMS is suggested for LTBA and LTFJ airports. By us-
ing the proposed new model in the terminal airspace, flight efficiency and predictability might be increased and
expected benefits of PMS could be appeared. In the future study, by using the real flight data, proposed PMS
STAR model will be compared with baseline procedures and results will be assessed in terms of flight time,
flight distance, fuel consumption and emissions.
References
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