Aircraft turnaround operation refers to the preparation work of an inbound aircraft for a following outbound flight that is scheduled for the same aircraft. Accordingly, activities of aircraft turnaround operation include both inbound and outbound exchange of passengers, crew, catering services, cargo and baggage handling. Technical activities in turning around an aircraft include fuelling, routine engineering check and cabin cleaning. Since passenger numbers and cargo/baggage loads vary from flight to flight, the realised turnaround time of an aircraft is stochastic in nature. Transfer traffic may occur at airports during the aircraft turnaround times such as flight/cabin crew, passengers and cargo/baggage. Under the complex resource connection mechanism among aircraft, disruptions may occur to any processes of aircraft turnaround and may consequently cause delays to departure flights. Disruptions such as connecting passengers, connecting crew, missing check-in passengers, late inbound cargo or equipment breakdown are normally seen in daily airline operations.
While disruptions caused by air transport system capacity reduction attracts much attention mostly because of its scale of impact, it is interesting to know that disruptions within this category account for roughly 40%~50% flight delays including those caused by weather. Other delay causes (the remaining 50%~60%) are contributed by airline operations in which reactionary delays may account for up to 20%~30% of the 50%~60% delay share, while technical faults may account for up to 10% (Eurocontrol, 2004; 2005). Delays cost money for airlines and the travelling public, no matter where the delays come from.
Punctuality data are mostly compiled from the time stamps acquired through the Aircraft Communication Addressing and Reporting System (ACARS). Time stamps may include take off time (wheel off), landing time (wheel on), arrival time (on-block at gates) and departure time (off-block at gates). However, operating data of ground handling, e.g. catering offloading start time and finish time, are hardly recorded by airlines. Given the crucial role played by ground operations in minimising knock-on delays in airline networks, it would be of tremendous benefits to airline operation control, if operational data is available during ground operations on a real time basis. This would allow operation controllers to pay precaution to potential events which might delay a departure and consequently cause delay propagation in the network.
The objective of this project is to develop an aircraft turnaround monitoring framework (ATMS) which serves as the platform to collect operational data to benchmark turnaround efficiency and calibrate PTS procedures of different aircraft types. Secondly, a monitoring system is developed based on the framework and serves as the real-time data feeding channel providing all involved units with high situational awareness of the up-to-date progress of turnarounds. The ATMS framework is implemented by using mobile devices and telecommunication network technology, namely GPRS (a widely used mobile phone network service, which provides internet access to mobile phone users). Given the environment in which ground handlers work on the apron and to minimise the inconvenience of entering data, Personal Digital Assistants (PDAs) are chosen as the mobile devices in this implementation.
Two screen shots of the ATMS implementation on Palm PDAs are shown. The main menu of ATMS as shown in Figure 1 includes six options: arrival, passenger, cargo, engineering checks, catering and departure. Arrival and departure options record only the on-block times of aircraft at gates, which are used as a reference to the ACARS arrival and departure time records. Under the passenger option, activities are listed on the PDA screen as shown in Figure 2. When an activity starts/finishes, the user can click on the activity and the time stamp of the corresponding activity will be stored on the PDA and transmitted via wireless network to the central database immediately via GPRS. The ATMS system was tested in April 2005 and January 2006. Results show the robustness of the system and the potential for future real-time turnaround operations control in the airline industry.
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