Quantifying the Impacts of Delayed Maintenance of Airport Assets: A Guide (2024)
Chapter: 4 Framework for Quantifying the Impact of Delayed Maintenance of Airport Assets
CHAPTER 4
Framework for Quantifying the Impact of Delayed Maintenance of Airport Assets
During the interviews with airport maintenance and operation managers in Phase I, the interviewees revealed that none of the airports have systematic methods of quantifying the regular maintenance budget and the impact of delayed maintenance on airport assets. The airport asset managers were preparing the maintenance budget based on their previous fiscal year budget. Some of the airports interviewed had a CMMS database, which they used to enter the maintenance cost and hours data; however, this database was rarely used to determine the maintenance budget of the airport assets. When asked about quantifying the impact of delayed maintenance of airport assets, none of the airports had any systematic process of determining the impacts. Therefore, airport asset managers need frameworks or tools to determine the impact of delayed maintenance on the airport’s costs. This chapter addresses the development of a general framework that can help determine the maintenance budget and the impact of delayed maintenance on airport assets when existing maintenance funds are insufficient. This framework can be used for any type of asset to quantify the impact on delayed maintenance. Chapter 5 will highlight the detailed processes of determining the maintenance budget and quantifying the impact of delayed maintenance on airport budgets for specific airfield and landside assets. Chapter 6 will discuss the tools that can allow airport maintenance and operation managers to determine their budget for specific assets with and without delayed scenarios.
Every airport should have asset management goals. The main goal of any airport asset management is to keep its assets in good condition so that planes can be landed safely and travelers can comfortably use the airport terminals and other facilities to reach their destinations on time. To achieve this goal, airport asset managers track, manage, maintain, and replace assets periodically, so that they can provide safe and easy air travel through their airports. To maintain these assets in good condition, asset managers should prepare short- and long-term maintenance and replacement plans. The maintenance budget required for every fiscal year needs to be prepared based on the condition of the assets. If funds are insufficient, then the priority should be given to assets with important maintenance needs that affect the safety and comfort of air travelers. Quantification of the impact of delayed analysis should be conducted by asset managers to determine what extra funds must be spent if regular maintenance is delayed by a certain amount of time. The quantification process should be provided to the airport’s higher-level authority to show them the consequence of delayed maintenance of the assets. To determine the consequences of delaying maintenance, the research team developed a framework that airport maintenance and operation managers can use. The framework shown in Figure 4-1 has seven basic steps:
- Defining airport asset maintenance and preservation policies.
- Keeping and updating an asset inventory database.
- Collecting assets’ condition data.
- Analyzing assets’ condition data.
- Identifying maintenance and replacement activities.
- Keeping and updating a maintenance and replacement cost database.
- Determining the maintenance and rehabilitation budget with and without delayed scenarios.
Delayed maintenance in the context of airport assets is defined as deferring maintenance of assets due to a lack of funds. Notably, some airport assets are critical to plane and passenger safety, which cannot be delayed. Delaying the maintenance of these critical assets will jeopardize the safety of the plane and passengers. However, for theoretical purposes, the research team has hypothetically delayed these activities to quantify whether delaying maintenance is economical. Also, when the impact of delayed maintenance was quantified, the research team did not consider the cost of shutting down airfield pavements and airport terminals. The team only calculated the extra maintenance cost spent on assets to bring them into good operating condition. The following section describes each of the above seven steps in detail.
4.1 Defining Airport Asset Maintenance and Preservation Policies
The first step in having a good asset management plan is to define the airport asset maintenance and preservation policies. These policies should align with the asset management’s overall goals. The policies related to asset maintenance should be developed to guarantee passenger safety. Similarly, the airport should build new infrastructure and maintain its existing infrastructure to ensure safety, mobility, and accessibility during air transportation. Airports should also develop and deploy innovative practices and technologies that improve the safety and performance of their airspace systems. Lastly, airports should serve with greater efficiency, effectiveness, and accountability.
Under these policies, the airport must prepare a long-term asset replacement plan. They should also identify the preventive and reactive maintenance activities to keep the assets in good condition and increase their life. The airport should define the assets’ target level of service, so that an adequate maintenance budget can be spent to maintain that level. Lastly, the policy should set decision criteria for maintenance intervention. An airport must prepare these policies before acquiring new assets so that they can be maintained properly.
4.2 Keeping and Updating Asset Inventory Databases
The first step of the asset maintenance plan will be to collect the airport asset inventory data. All the assets in the airports’ possession need to be kept in a database. Airports use several types of software to keep asset inventory, such as PAVEAIR, IBM Maximo, GCR’s ASOCS, and Veoci. Airports generally use the term CMMS to refer to software systems like the above-mentioned proprietary software brands, or databases to keep asset inventory. This software not only holds asset information but also analyzes the asset data to assist asset managers in making informed decisions. Airports have a variety of assets, and these can be classified as airside or landside assets. The airside assets include, but are not limited to, airfield pavement, markings, signs, lighting, NAVAIDS, utilities, fencing, gates, and drainage. The landside assets include passenger boarding bridges, baggage handling systems, HVAC systems, pickup trucks, loaders, snow blowers, hangers, fueling facilities, administrative buildings, terminal buildings, overhead bridges, and parking garages. Generally, the asset inventory database consists of information related to the location, age, condition, and maintenance cost spent on the assets (labor hours and parts spent on maintenance). Some airports use radio-frequency identification (RFID) and sensors to determine the assets’ exact location. If the asset inventory has the required information, it will be easy for asset managers to prepare a regular maintenance budget and long-term replacement plan, as well as quantify the impact of delayed maintenance.
4.3 Collecting Asset Condition Data
If the asset conditions are not assessed every year to determine their remaining life, then it will be difficult for airports to prepare maintenance budgets and develop a long-term replacement plan. During the interview in Phase I, five interviewees stated that they assess the conditions of some of their assets. All the airports interviewed have a conditional assessment of their airfield pavement. Every year the airports’ in-house staff or consultants conduct the conditional assessment of the pavement and determine the PCI. The large-hub airports use PAVEAIR to store and analyze the pavement condition based on these PCI values. This value plays an important role in maintaining the airfield. Some airports also assess the condition of airport signs by rating the signs excellent, good, fair, and poor. These ratings help to determine the maintenance budget allocated to airport signs. The airports collect data on assets’ conditions but do not have specific measurement metrics to determine them. For example, in airfield marking and lighting systems, airports assess their condition every year by checking the markings’ reflectivity, lightings’ electrical connection, and light fixtures. However, no formal process exists to record the condition of these assets in the database software. Similarly, the airports keep their inventory and check the assets’ conditions but do not categorize their assets’ condition levels for some landside assets, including baggage handling systems, HVAC, passenger boarding bridges, pickup trucks, loaders, and ARFF equipment. Generally, the airports depend upon their age, usage hours, or usage mileage to determine the asset conditions. For example, for pickup trucks, the airports record the mileage and determine the condition of these vehicles. Similarly, for loaders, they use the hours of operation to determine the conditions. For other landside assets, the airports interviewed use the assets’ age to determine their condition. It will be easier for airports to prepare the maintenance and replacement budget as well as determine the impact of delayed maintenance if asset conditions are categorized.
4.4 Analyzing Asset Condition Data
Airport asset managers must analyze the asset condition data before preparing a maintenance budget with or without delayed maintenance. Asset condition data can be used to prepare the asset deterioration model. All the airports have their PCI data which can be used in PAVEAIR to determine the regular deterioration trend of any type of pavement (asphalt or concrete). Asphalt and concrete already have established deterioration models based on PCI values, but, for other assets like pavement markings, airfield lights, or airport signage, it is difficult to determine the empirical models like that of pavement. Most studies have used the random probability theory based on asset life to determine the cumulative failure probability of the assets. If the asset conditions can be categorized on some level (e.g., excellent, good, fair, or poor), then it will be easier to determine how the asset conditions could change each year. Also, if the asset data are collected over the course of a few years, these data can be used to determine the probability of the asset changing from one condition category to another. Categorizing the condition of the asset helps to develop deterioration models. The condition of some landside assets should be categorized as excellent, good, fair, or poor, and their condition data should be collected throughout the life of the asset. Using these data, the probability of converting these assets from one condition to another can be determined more easily. Some car and pick-up truck companies have determined the probability of failure by using the collected asset condition data. Collecting and analyzing these kinds of data requires commitment and resources that airports do not readily have access to.
Although the condition data are available, it can still be difficult for airports to develop regular deterioration models for most airport assets due to a lack of systematic data. Researchers need to depend upon theoretical models of probability to determine asset deterioration based on scenarios without maintenance. It is not possible to collect the condition data without any maintenance, because the airport cannot leave assets without preventive maintenance. Therefore,
the deterioration models in delayed maintenance scenarios must depend upon the researchers’ assumptions and probability distribution theory. In this research, assumptions and theoretical probability distribution theory are primarily used to develop asset deterioration models that do not include preventive maintenance.
4.5 Identifying Maintenance and Replacement Activities
Every airport must identify the types of maintenance activities that need to be performed on their assets so that their lives can be prolonged. The assets cannot be maintained properly without knowing the maintenance activities and frequency, and it will be difficult to determine a budget without that information. Maintaining asphalt and concrete pavements involves different activities. Some maintenance activities performed on asphalt pavement include cold chip sealing, cold in-place recycling, cold milling, crack filling or sealing, or fog sealing. However, crack sealing, diamond grinding, diamond grooving, or dowel bar retrofitting activities can help the concrete pavement remain in good condition. Similarly, for HVAC systems, changing the airlifter regularly, cleaning the duct system, greasing the belt and motor, and maintaining the air handling system are required to keep the HVAC in good running condition. In the case of baggage handling systems, the motor of the belts needs to be greased and changed, and the conveyor belts need to be inspected and repaired to increase the life of the system. Airport asset managers need to ensure that the required maintenance activities are performed with appropriate frequency. It is also necessary to determine what activities need to be performed if the assets need replacement.
4.6 Keeping and Updating Maintenance and Replacement Cost Databases
To determine the maintenance and replacement budget, a cost database calculated using the cost of materials and labor needs to be prepared. Therefore, for all maintenance activities identified in the previous step, the airport asset managers should track the labor hours and parts required to perform these activities. If the labor productivity and parts required for maintenance are kept in a database, it will help determine the cost of maintenance. The research team found that most of the airports do not have this type of database to determine an accurate maintenance budget with and without delayed maintenance.
4.7 Determining Maintenance and Replacement Budgets with and without Delayed Scenarios
Asset deterioration models, maintenance and replacement activity types, labor productivity, and cost of labor and parts can determine a regular maintenance and replacement budget. The maintenance budget for the coming fiscal year needs to be prepared based on the predicted conditions of the assets in that year, necessitating an accurate deterioration model. Airport asset managers need to identify the types of preventive maintenance and their frequency to correctly calculate the budget. Productivity and cost data also need to be updated regularly to ascertain an exact budget. Delayed maintenance and replacement costs can be determined by using deterioration models prepared for the delayed scenarios. The accuracy of a maintenance and replacement budget for any asset will depend upon all factors mentioned in the above steps. These are estimated budgets, so there will always be variations when used during the maintenance implementation phase, but an effort must be made to increase accuracy and minimize variations between the estimated and actual budget.
