CHAPTER 5 CHAPTER 5
5.6 Maintaining Readiness Maintenance Management
The primary concern of operations management is to ensure the continuous availability of all operational services. To achieve this, a systematic approach to maintenance management is called for, the extent of which will depend on the types of operations at a particular airport. Clearly, a major air carrier hub will require a vastly more complex maintenance program than an airport dealing only with general aviation (GA) types of operations. There are two essential aspects, however, that will be common to any airport maintenance program:
• A documented schedule of routine maintenance
• A comprehensive system of maintenance records, including costs
FIGURE 5.6 Regularly scheduled inspection checklist.
Many of the airport facilities, such as radio communications, radio and radar approach aids, and airfield lighting, are of such critical importance to flight safety that every effort has to be made to ensure that failures do not occur. Among the elements involved are
• Radio communications (air/ground) transmitters and receivers
• Aeronautical fixed telecommunications
• Telephones
• Approach and landing aids
• Lighting
• Fire and rescue services
• Aircraft movement areas
• Power plant and distribution system
Preventive Maintenance
The process of preventive maintenance is concerned mainly with regular inspection of a system and all its component parts with the objective of detecting anything likely to lead to a component or system failure and taking appropriate action to prevent that happening.
Such action might involve cleaning or replacing parts on a predetermined schedule.
Whatever the action called for, this cannot be determined in the first place unless a planned inspection schedule is established. An example of a preventive maintenance schedule for medium-intensity approach lighting is given in Table 5.5. Runway lighting is somewhat simpler to maintain, but the same systematic inspection is required (Table 5.6). Centerline and touchdown-zone lighting will, of course, be much more vulnerable to damage as a result of being run over by aircraft. The fact that they are located below ground level also makes them vulnerable to water infiltration.
Source: FAA (2009).
TABLE 5.5 Preventive Maintenance Inspection Schedule for Medium-Intensity Approach Lighting
Source: FAA (2009).
TABLE 5.6 Preventive Maintenance Inspection Schedule for Centerline and Touchdown- Zone Lighting Systems
Electrical Maintenance
There are few systems on an airport that do not depend in one way or another on electrical power. Indeed, the power requirements of modern airports are equal to those of small towns. Operational facilities, especially those concerned with aviation technical services, make heavy demands on the public power supply. Standby power must be available to provide a secondary power supply to these essential services in the event of breakdown of the main supply. The arrangements for a secondary power supply depend in part on the switchover-time requirements, that is, the time interval between loss of power and the availability of a secondary supply (FAA 1986). This could be critical in the case of precision-approach aids or lighting, as indicated in Tables 5.7 (FAA 2009) and 5.8 (ICAO 2006), respectively. The demands range from a maximum permitted interruption of 15 seconds to zero or completely uninterrupted supply, as in the case of an ILS localizer and glide slope for Category II and III approaches. The source of secondary supply usually is one or more diesel-driven generators. In the case of a zero-switchover-time requirement, the arrangement is to have these facilities supplied by a generator with a coupled energy- storage flywheel.
Source: ICAO (2006).
TABLE 5.7 Recommended Switchover Times in the Event of Power Failure: Lighting
Source: ICAO (2006).
TABLE 5.8 Recommended Switchover Times in the Event of Power Failure: Ground-Based Radio Aids
The generator is driven by an electric motor. In the event of a main power failure, the generator derives the required driving power from the flywheel until the coupled standby diesel generator takes over the full load. To further safeguard the remote possibility of the generator failing, a second generator is coupled in parallel with the first.
Such stringent requirements as these call for an appropriate level of maintenance and, alongside this, a suitable level of workforce. The requirements for maintenance personnel in a typical airport electrical shop (Category II airport) are listed in Table 5.9.
Source: Frankfurt Airport.
TABLE 5.9 Personnel Requirements in a Typical Electrical Shop of a Category II Airport
Operational Readiness: Aircraft Rescue and Firefighting
There is one essential element of the operating system—the rescue and firefighting service (RFFS)—where maintaining readiness applies as much to personnel as to machines.
Opportunities for RFFS personnel to carry out their assigned tasks under “real” conditions fortunately are rare; as a result, they can maintain readiness to deal with an aircraft accident only by constant practice. It is especially difficult to maintain a peak of performance under these circumstances, and it is for this reason that facilities should be provided for “hot fire” practices and, also if possible, for practices in smoke-filled confined spaces, preferably simulated aircraft interiors.
Some airports employ independent aircraft and firefighting services. It will be important in these cases to carry out occasional tests of the ability of the personnel and equipment to meet the required performance criteria (see Chapter 12) and in particular to test their communications and coordination procedures.
Safety Aspects
Whether maintaining electrical or mechanical systems, the nature of maintenance work exposes those who carry it out to certain risks, including natural phenomena such as lightning strikes while working out on the airfield. A comprehensive set of guidelines on dealing with risks should be drawn up by management. The nature of these risks can be indicated by an examination of some of the common causes of accidents:
• Working on equipment without adequate coordination with equipment users
• Working on equipment without sufficient experience on that equipment
• Failure to follow instructions in equipment manuals
• Failure to follow safety precautions
• Using unsafe equipment
• Failure to use safety devices
• Working at unsafe speeds
• Poor housekeeping of work areas
The FAA issues guidelines on continual checking of the safety conditions at an airport through its program of Airport Safety Self-Inspection (FAA 2004). Where safety-related matters require action by the operations department of the airport company or authority, these actions will be coordinated through the airport operations control center (see Chapter 16).
Most air carrier airports will have a multiplicity of electrical and mechanical systems with large amounts of associated equipment requiring continuous checking and servicing by skilled maintenance personnel. The extent of this work will very much depend on the amount and type of aircraft operations, the weather categories in which the airport operates, and the number of passengers, visitors, and staff using the airport.
With the increasing sophistication (and complication) of the equipment used at airports, the use of automatic equipment/system monitoring to provide prompt warning of equipment failures, once limited to certain airport operational facilities (e.g., ILS, lighting), is now a commonplace application for all key installations. These systems also can provide comprehensive performance records and interface with other airport control systems, as
well as logistics systems for maintenance work orders and spare-part availability. But a vital element for achieving the exacting state of readiness needed in air transport is for airports to have available the resources/workers and materials to enable a rapid and effective response to any deficiencies in the airport’s operating infrastructure.
Airfield Construction
Despite good maintenance programs, the airport operator will find that major airside repairs will be necessary at some time, which inevitably will introduce construction activities to the movement area. Obviously, the visual guidance systems on the airside, which ensure the safe and expeditious flow of aircraft, vehicles, and personnel, are not designed to accommodate construction activities. Significant safety planning is an absolute must.
Construction on or near the movement area is inherently dangerous because it introduces several additional risk factors to an already challenging environment from the point of view of safety management. Factors that increase risk begin first simply with the transit of additional personnel and vehicles in and out of the movement area through temporary access points—with the concomitant risks of unauthorized access of personnel and additional vehicles with potential for runway incursions. Second, construction frequently changes the circulation of both vehicles and aircraft in the movement area; thus other operators, accustomed to the original pattern of movement, have to adapt to a change in the environment. Third, the introduction of untrained personnel to the movement area, unfamiliar with the rules and risks of their new environment, creates serious control challenges. Fourth, construction equipment and barriers create obstacles that require marking, lighting, and monitoring. Fifth, construction activities themselves create dust, debris, and noise, which can adversely affect the safety of the movement area.
Adequate management of these risks begins with a good contract-procurement system that ensures that contractors who are awarded work on or near the movement area have good safety-management programs, proper equipment, and insurance policies appropriate to the risk of working airside. The next step is to implement a thorough airport permit system based on the satisfaction of certain safety requisites. No work should begin without the knowledge of ATC and apron management. In cases where airside construction work goes beyond what would be considered normal maintenance activities and affects air traffic, publication of a NOTAM likely will be required.
The permit application should be accompanied with a detailed work plan, with precise movement routes, communication procedures with ATC and apron control, evacuation procedures, scheduled briefings, construction inspections, turnover procedures, and control measures (including equipment inspections, cleaning, dust control, and obstacle marking).
In addition, the work should be planned to coincide with periods of lower activity. Avoid peak periods, if possible.
The submitted work plan will be subjected to a risk analysis by the aerodrome operator’s safety management team. Safety management systems cover the main elements of risk management (i.e., hazard identification and mitigation), including some obvious safety measures that should be taken into account (see also Chapter 16):
• Isolation of the work area with correctly marked barriers
• Use of reflective vests by construction personnel, in addition to normal personal protective gear
• Daily safety briefings of personnel to ensure that they are aware of work limits, authorized access routes, communication procedures, and inherent dangers on the apron (e.g., jet blast, FOD, and collisions)
• Assignment of a works coordinator, in constant communication with ATC and apron control
• Vehicle inspections to ensure serviceability, sufficient fuel for evacuation, proper markings, and absence of FOD in tires
• Protection of loose material from wind and rain erosion
• Strict adherence to authorized work hours
• Take into consideration security aspects linked to outside workforce
All these controls should be detailed in the work plan and implemented during construction.
The airport operator will have to inspect daily for compliance. Work progress should be monitored as well by the engineering or maintenance department to ensure that required changes to the work hours or extension of the work period is anticipated with enough advance warning to gain approval and properly inform ATC, apron control, and operators using the movement area.
As a final consideration, while all work in or near the maneuvering area presents a serious risk that must be managed, work within the runway strip is subject to special restrictions. Annex 14 divides the obstacle-free zone surrounding the runway strip into three zones. While the limits vary according to airport classification, the following are typical:
• 197 feet (60 m) from the runway centerline—very limited work area [30 to 92 square feet (9–28 m²)], obstacle height restricted to 3.3 feet (1 m)
• 197 to 246 feet (60–75 m) from the runway centerline—work area not restricted, obstacle height restricted to 6.6 feet (2 m)
• Beyond 246 feet (75 m) from the runway centerline—no work-area limits
If construction work that cannot comply with these restrictions must go forward, a runway closure likely will be required.
Conclusion
The most critical task of an airport operator is to ensure the safe, reliable, and expeditious movement of aircraft, passengers, and cargo through the airside to landside and vice versa. A systematic approach is necessary to ensure the operational readiness of the critical facilities that make such movement possible. ICAO, as well as several Member States, has developed certification criteria that describe the minimum standards for operation of these facilities. For further information, the reader is urged to refer directly to ICAO Document 9774, Manual on Certification of Aerodromes.
References
Civil Aviation Authority (CAA). 2010a. Air Navigation: The Order and the Regulation (CAP 393). London: CAA.
Civil Aviation Authority (CAA). 2010b. The Assessment of Runway Surface Friction Characteristics (CAP 683).
London: CAA.
CFR 2004: Airport Certification. Code of Federal Regulations, Part 139. Washington, DC: Office of the Federal Register, National Archives, and Records Administration.
Federal Aviation Administration (FAA). 1986. Standby Power for Non-FAA Airport Lighting Systems (AC150/5340- 17B). Washington, DC: FAA, Department of Transportation.
Federal Aviation Administration (FAA). 1989. Airport Design (AC150/5300-13, changes 1-13). Washington, DC:
FAA, Department of Transportation.
Federal Aviation Administration (FAA). 1991. Runway Surface Condition Sensor Specification Guide (ACJ50/5220·13B). Washington, DC: FAA, Department of Transportation.
Federal Aviation Administration (FAA). 1992. Airport Snow and Ice Control Equipment (AC150/5220-20).
Washington, DC: FAA, Department of Transportation.
Federal Aviation Administration (FAA). 2004. Airport Safety Self-Inspection (ACI5015200-18C). Washington, DC:
FAA, Department of Transportation.
Federal Aviation Administration (FAA). 2007. Guidelines and Procedures for Maintenance of Airport Pavements (AC150/5380-6B). Washington, DC: FAA, Department of Transportation.
Federal Aviation Administration (FAA). 2008. Airport Winter Safety and Operations (ACI50/5200-30C). Washington, DC: FAA, Department of Transportation.
Federal Aviation Administration (FAA). 2010. Airport Foreign Object Debris (FOD) Management (AC150/5210-24).
Washington, DC: FAA, Department of Transportation.
International Civil Aviation Organization (ICAO). 1983. Airport Operational Services (Document 9137) in Airport Services Manual, 1st ed. Montreal, Canada: ICAO.
International Civil Aviation Organization (ICAO). 1984. Airport Maintenance Practices (Document 9137) in Airport Services Manual, Part 9, 1st ed. Montreal, Canada: ICAO.
International Civil Aviation Organization (ICAO). 2001. Manual on Certification of Aerodromes (Document 9774) in Airport Services Manual, 1st ed. Montreal, Canada: ICAO.
International Civil Aviation Organization (ICAO). 2002. Pavement Surface Conditions (Document 9137) in Airport Services Manual, Part 2, 4th ed. Montreal, Canada: ICAO.
International Civil Aviation Organization (ICAO). 2010. Annex 14: Aerodromes, Vol. 1: Aerodrome Design and Operations, 5th ed. Montreal, Canada: ICAO.
International Civil Aviation Organization (ICAO). 2011. Bird Control and Reduction (Document 9137) in Airport Services Manual, Part 3, 4th ed. Montreal, Canada: ICAO.
1This chapter was reedited and rewritten by William Fullerton.
2The subsequent calculation method is now performed routinely by computer programs. The manual example is shown for instructional purposes only.
3For Airport Reference Codes A-II and B-II, the FAA mandates that the maximum allowable crosswind component is 13 knots. This is also the ICAO standard for similar airport designs.