LPV – what’s the hold up? (Part 1 – the aircraft operator)

Written by: Philip Church
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Ever since the mid-1990s it has been recognised that augmentation of GNSS signals (GPS to begin with) would improve the integrity of the signal such that it could be used for navigation by aircraft. The potential cost and safety benefits were tantalising, but as with all things aviation, they have taken years to materialise – and we are not quite there yet!

It took until 2011 for Europe to declare the operational certification of EGNOS, enabling the deployment of LPV (Localiser Performance with Vertical guidance). These procedures can be deployed without the need for ground infrastructure and with minimal training of flight crew, delivering operational performance near to that of an ILS approach (200ft and ½ mile visibility). They also integrate seamlessly with the PBN concept. So, given these benefits of reduced cost and safety improvements (especially at aerodromes without ILS), how can we accelerate the deployment and utilisation of LPV procedures which are currently predicted to reach 25% coverage by 2018?

As with most technical deployments in aviation, LPV requires active participation from three stakeholders:

1. The aircraft operator must see an operational benefit in equipping their aircraft to utilise these procedures and request their deployment at destination aerodromes within the EGNOS coverage area.

2. The aerodrome must commission the design of the LPV approaches to the requisite minima. Awareness of the processes involved and the competencies to complete these activities rarely reside within the aerodrome itself. It is likely to be dependent on an Air Navigation Service Provider (ANSP) or other external providers. In recent years Helios has managed the LPV approach implementation for nine different aerodromes across seven different countries. Experience has shown us that an LPV approach project offers additional benefits beyond those immediately envisaged – including the chance to rationalise navigation infrastructure and other airspace improvements.

3. The ANSP needs to publish the procedures. In many cases, the ANSP also does the procedure design and must develop the safety assessment with the aerodrome prior to publication.

This, then, is the crux of the problem: without procedures, aircraft operators are less willing to equip and without aircraft operators willing to use the procedures, aerodromes are less willing to invest in procedures. Crucially, with institutional support in the form of ICAO resolutions and European PBN Implementation Roadmaps, there is now a gradual increase in procedure availability. So, in the first of a three part blog we share some observations on the issues to address as well as some ideas for accelerating deployment, taking each stakeholder in turn, and starting with the aircraft operator.

From the aircraft operator's perspective, the decision to deploy and use LPV is complex. Not only does the aircraft need to be equipped with approved avionics and airworthiness approval obtained, but the operator also needs operational approval. This combined with the high cost of implementation can present a barrier – especially where retrofit is required. Even with aircraft already equipped the operator cannot benefit until operational approval is obtained.

We have looked at the costs for aircraft upgrades several times on behalf of operators both individually and within the context of European FP6 and FP7 programmes such as GIANT and ACCEPTA. Back in 2013, we undertook a detailed cost-benefit analysis of LPV implementation for a regional airline. The aim was to determine the level of operational benefit if its aircraft were equipped with suitable avionics. In our experience, the case for aircraft operators can rarely be made on a single destination but rather on the network effect. So an early activity was to establish fleet use within the operational network. We created a robust and re-usable model incorporating fleet data, route structures and number of predicted MET disruptions experienced at network airports depending on the available approach capabilities. The model showed that for this particular airline and route network a 30% equipage rate was required to deliver overall benefits. Whilst costs increased linearly with the number of aircraft fitted, the benefits were non-linear – starting high for a low number of aircraft, and then marginal benefit diminished as the number of fitted aircraft approached 100%. The work also paved the way for some interesting discussions on how airlines might take advantage of other Single European Sky (SES) Implementing Rules (such as PBN) to gain additional capabilities at reduced cost.

In this particular example, benefits were restricted by the availability of alternative ILS infrastructure at a number of routes. Whilst this is the case today for a majority of aerodromes served by regional airlines, our analysis clearly demonstrated that tangible benefits can be obtained from even low fleet equipage and strategic aircraft utilisation. As more regional aerodromes see the advantages of reduced infrastructure costs and minimal disruption, LPV will become more beneficial to aircraft operators using these aerodromes. However, LPV is but one of many changes that operators have to consider within the evolving European ATM context. Here Helios is able to use its technical and regulatory knowledge to assist operators looking for single step and cost-effective solutions that fit with their route network.

In part two of this blog, we will look at the aerodrome perspective, the process involved in designing an approach and some of the additional benefits that can arise.

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