Following investments in advanced mobile and workshop photometric measuring equipment, and the adoption of an integrated Aeronautical Ground Lighting (AGL) maintenance methodology, Manchester Airport, UK has not only been able to bring the performance of its expanded AGL system up to, and exceed, required standards, but the airport is also now in a position to realise real savings in whole life system costs.
Manchester Airport has experienced significant expansion over the past decade, including the building of a second runway and huge new terminal facilities. It is now the UK’s third largest airport, handling over 28 million passengers, and managing over 210 000 air transport movements, per year. In such an active environment, it is vital that the performance of any operational system meets or exceeds the required standards. This is especially true of a safety critical service such as Aeronautical Ground Lighting (AGL).
AGL systems (covering runway centreline, touchdown zone, edge and taxi-way lights) support safe and regular aircraft operations by providing essential visual guidance to pilots and aerodrome personnel, and over the past few years their importance and performance has come under much greater scrutiny. Yet, although a minimum AGL operating criteria has been established by the ICAO (Annex 14) and the UK CAA (CAP 168), most recently, the FAA (AC 150/5340-26A) has also produced far clearer recommended guidelines for the minimum performance standards. However, the reality is that many airports still struggle to maintain these requirements; this has been highlighted by research undertaken by TMS Photometrics for the UK CAA.
The reasons for this situation is mainly due to the inadequacies of the traditional monitoring and maintenance practices still employed by many airports, which fail to take account of all the unpredictable factors (from installation practice and lamp aging to dirt build up) that contribute to the variations in performance of light fittings. In fact, it has now been recognised that these old approaches are no longer sufficient to maintain systems within the new standards being set by all authorities. The consensus of ICAO, CAA and FAA is that to effectively meet performance level objectives, requires a combination of using a mobile measuring unit on a routine basis to analyse the characteristics of individual lights, and the adoption of new preventive maintenance approaches.
Manchester Airport has not only recognised the importance of maintaining its AGL systems to internationally recognised standards, and being able to prove compliance, but has over the past few years done something about it by turning to the specially developed technology and maintenance practices that are now being recommended. This has meant investing in MALMS (Mobile Airfield Light Monitoring System), TMS Photometrics’ unique, high technology, mobile photometric measurement system and adopting the company’s Differential Maintenance approach.
Working Blind
Like most airports, Manchester previously employed a traditional approach to the maintenance of its AGL services- replacing lamps when they were obvious failures, cleaning all fittings as regularly as possible, and undertaking a full lamp block changes – the removal and complete refurbishment or replacement of all fittings – on a six months cycle.
But as Mike Curry, Manchester Airport’s Airfield Systems Manager, explains, “We had no information as to the actual performance of these fittings prior to the block change. Equally, we had no way to really check how effective this maintenance actually was, both in terms of improving the performance of the AGL, and whether the cost of complete refurbishments (including lamp and lens replacements) was required. We undertook the process on a regular basis, as this was the accepted practice at the time – and still is in many airports.”
The realisation that accepted practice was no longer a viable option came after some initial inspections of the AGL system by TMS Photometrics. “Our findings clearly highlighted that the airports existing maintenance approach not only produced highly variable AGL system performance, but also potentially higher than necessary maintenance costs,” – TMS Photometrics.
The result was that Manchester Airport started down the path of a major development of its lighting maintenance practices, with the initial aim of implementing a strategy that would effectively meet CAA requirements and as efficiently as possible improve AGL performance consistency to within the required standards.
To this end, its first step was to purchase MALMS Mobile, a trailer based system that has been specifically developed to enable the rapid, accurate and regular measurement of the photometric performance of both inset and elevated AGL runway services, against the criteria for beam intensity and orientation defined in ICAO Annex 14. However, while measurement can demonstrate compliance, or lack of it, it cannot ensure compliance. To deliver this requires an integrated maintenance approach. Therefore, the airport also adopted ‘Differential Maintenance’; a methodology that has also been developed by TMS, in association with the UK CAA and supporting UK aerodromes. This closed loop approach uses the photometric measurement data to target cleaning and replacement activity and has been proven to enable serviceability levels to be maintained in an effective and efficient manner.
Achieving Compliance
The maintenance operation now undertakes up to eight photometric measurement runs per week, across its two runways. This typically involves the centrelines being measured twice weekly, the edge lights measured weekly and the TDZs around every two weeks. With runway access time very limited, MALMS’ ease of use, which enables runs to be completed very quickly, has proven essential to this level of monitoring.
The findings from these runs are then used to target maintenance activity – be it cleaning or replacement – for the next few nights on the specific fixtures and areas that need it. After the work is completed, the next run is used to assess effectiveness. “Previously we would remove and replace the whole centreline of 200 lights, regardless of condition. Now, we might target only 20-30 lights at a time, clean them, and then only if performance does not improve sufficiently do we remove and refit,” notes Curry.
One of the first interesting outcomes from the adoption of the new technology and approach was the finding that AGL performance deterioration due to rubber deposits was generally both far more rapid and variable than previously thought. “This was a real eye opener,” reports Curry. “It soon became clear that there were more effective methods of determining cleaning needs than simply undertaking regular cleaning.”
The installation of the airport’s second runway also highlighted another area where performance variation can be easily introduced. Using the MALMS system, a commissioning run was undertaken to determine the new AGL’s compliance, and this discovered several alignment issues. These were soon rectified by the installer, but as Curry comments, “By being able to easily, accurately – and independently – test the system, we ensured that its performance was up to specification from the outset, and this also meant we started off with a known level as a base line for our maintenance strategy.”
Overall, the new maintenance approach has, as anticipated, provided a very effective way to deal with all the variable factors that can affect an AGL system. As a result, while many airports are still struggling to even determine the level of their non-compliance, Manchester Airport quickly saw the effectiveness of its maintenance improve to a point where its core AGL system is now constantly maintained to a verifiable performance level that is well in excess of the minimum standards.
Finding Efficiencies
While the ability to comply with the AGL performance standards was the initial driving force behind the adoption of the new technology and practices, Manchester Airport is now also finding that having valid performance data offers massive potential for finding waste, improving overall process efficiencies and reducing whole life costs.
Curry states, “There is no doubt that we have increased monitoring and cleaning the AGL fixtures than previously. But, at the same time we now have the data that confirms the impact that the cleaning has, which is significant, and we are only maintaining what needs to be maintained. So, we have seen reductions in some other cost areas, as we generally do not refurbish fittings as often as before, and we can better manage labour, as the workload is far more regular, and we no longer have the high concentrated peaks and troughs of work.”
He adds, “We also starting to use the data from the MALMS system to monitor the performance of various fittings over time and investigate life cycle costs. This ability will have significant impact on future costs.”
For a start, the maintenance team is now collating performance data that indicates the level of impact that fitting design has on overall performance and the need for cleaning. This is already suggesting that some fittings are far better than others for not catching dirt, and are easier to clean properly; information that will prove important when determining future replacement purchasing policy. The measurement technology also means that it is now possible to run specific evaluation tests by placing a selection of fittings, from different manufacturers, into set locations and then monitoring them to see which offer the best whole life performance. In fact, such an exercise is already being conducted for edge lights, and the data will be used in selecting the fittings to be purchased for the whole service. “We are now able to make purchasing judgments based on our own data,” says Curry.
The Power of Knowledge
In another move aimed to further enhance maintenance efficiency and reduce costs, the airport has also purchased the MALMS Photometric Bench. This self-contained and compact testing equipment, produced by TMS, has been specifically designed to provide fast, repeatable and semi-automatic methods for testing the performance of individual AGL fittings (to ICAO specifications) in a maintenance workshop. In practice, this equipment essentially closes the maintenance loop, by ensuring the performance of new and refurbished fittings prior to installation in the runway.
Until this latest investment, the maintenance staff had no way of testing for refitting errors or new component (or even new product) failures, until the fittings had been reinstalled and subjected to a full MALMS run. As a result, it was not uncommon for a MALMS run to pick out a fitting that was under performing, for it to be brought in and worked on and then put back, only to find on the next run that it was still performing below requirements. Similarly, it was not unheard of for completely new fittings to perform below standard from the outset.
Curry states, “We now have the equipment and data to determine the real source of any refurbishment problems. New practices are being put in place to ensure that new parts are being installed correctly, and that we check for both faulty components, and test all new fittings from manufacturers. By being able to weed out these problems at source, we are now seeing the rapid elimination of the wasted time, effort and cost that was caused by having to re-place newly installed fittings that were performing below requirements.”
In addition, tests undertaken using the Photometric Bench have also provided some very interesting findings concerning lenses. Previously it was up to the maintenance engineer to determine, based on visual inspection and experience, if a lens in a poorly performing fitting needed replacing. But, in general, they would often be replaced during the refurbishment. Yet, Manchester Airport is now finding that the pitting and scratches on the lens surface have much less effect on a fitting’s light output performance than previously thought. Even if this knowledge only stops one unnecessary lens replacement for each runway fitting per year; at around £30 per lens and well over 2000 fittings, this soon adds up to a significant saving.
Through the adoption of MALMS, Differential Maintenance and the Photometric Bench, and the subsequent generation of real data, Manchester Airport’s maintenance staff now have clear picture of actual system and element performance, both immediate and over the long term. As a result, they have the knowledge to enable far greater control over effective activity – determining when to maintain and what sort of maintenance is needed – and to establish a much better understanding of the system’s life cycle costs.
As Curry concludes, “We now have a knowledgeable process, and this is now providing us with the capability to not only ensure that our AGL system performs well within the required standards, but at the same time drive out process waste and reduce costs.”