CASE STUDY: AOC Datalink for operational fuel efficiency at Vueling

Author: Jasone Echanojauregui Garriga, A320 First Officer and Laura Perez Bermudez, Flight Operations Engineering Manager, both Vueling

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Jasone Echanojauregui Garriga, A320 First Officer and Laura Perez Bermudez, Flight Operations Engineering Manager, both with Vueling, and Petr Frolík, Commercial Director, NAV Flight Services share implementing AOC Datalink for operational fuel efficiency through automation of preflight phase, plus tailored real-time wind uplink

This case study is about the implementation of the AOC (Airline Operation Control) Datalink in Vueling Airlines.

THE NEED FOR A NEW SOLUTION

As part of the airline’s transformation plan, Vueling faced key challenges that required focused action as outlined in figure 1.

Figure 1

It is a top priority for Vueling to reduce pilot workload in order to minimize the risk of fatigue and its potential impact on the performance of the flight. Also, given that fuel is one of an airline’s main costs, there is a perennial focus on fuel efficiency and, with sustainability goals in mind, there is a clear need to improve fuel consumption. To address these two issues, Vueling decided to focus on the pre-flight and descent phases, which were felt to offer the most potential for optimization. To achieve this, required a communications technology that enables the digital exchange of information between the aircraft and the ground systems and for that, we needed a Datalink based solution.

The requirements for an aircraft operator to implement AOC Datalink are really straightforward. First, you need to provide an Operational Flight Plan (OFP) to datalink service provider, regardless of the flight planning solution being used. Then, you have to set up AMI (Airline Modifiable Information). You also need an operative aircraft ACARS system. The only item that readers might not be familiar with is the AMI; this is the kind of configuration database of the FMS (Flight Management System) that allows an airline to enable upload of flight data information via Datalink.

For the implementation of Datalink, Vueling decided to define an MVP (Minimum Viable Product) and divide the project into three phases. The first one was the longest and took around 30 weeks, mainly because there were a lot of internal discussions at the beginning to understand the need and how it could be addressed. Also, the AMI had to be configured and installed across all of Vueling’s fleet. But, by phases two and three, we managed to halve the implementation time because the people involved were used to working together, and it was not necessary to make a lot of changes to the processes. Also, the AMI was already installed, so there was no need to do any kind of modification.

THE SOLUTION

Once the need had been identified, to implement Datalink, Vueling selected NAVlink from NAV Flight Services. The methodology followed for the implementation started with a brainstorming session where airline and provider defined the scope of each phase and the features on which the airline wanted to work. Then some ground tests were run to validate the behavior and the results and, after that, NAV Flight Services started working on the feature implementation. Once this was completed, some test flights with selected pilots were scheduled to validate the features and for them to provide feedback, from which adjustments were made if needed. After that. and after documenting procedures and communicating to the crews, these features were launched across all Vueling fleets. Figure 2 shows the three phases of the of the project, how the project was organized, the key milestones and the challenges that were faced.

Figure 2

there were a lot of discussions at the beginning, mainly around IT architecture, and the AMI configuration. This was needed because it avoided extra cost in the future and ensured the engagement of all stakeholders on the project. From that experience, we have concluded that it’s really important to be open minded on collaborative working in this kind of project; also, to establish tight collaboration between the airline and the provider, to be able to quickly adjust the features based on crews’ needs. Also to involve the safety and compliance department from early in the project, so that all the company is aligned and there isn’t a surprise at the at the end of the implementation.

The selected solution, NAVlink from NAV Flight Services, delivers the flight plan and wind uplinks via ACARS to the flight management system as shown in figure 3.

Figure 3

IMPLEMENTING AND USING THE SOLUTION

Figure 4 shows the full timeline for the development from kick-off in May 2023 to to implementation and launch in December 2023, May 2024 and January 2025.

Figure 4

Phase 1

Initially, the system was designed to respond to the request from the flight management system where the pilot is supposed to enter the call sign, which is quite standard. Less usual is that, due to the fact that Vueling had the opportunity to define the AMI, they can also use additional information from the scratchpad but, in this case, it was the version of OFP. The reason was to make sure that the flight crew receive exactly the same route as in their pre-flight documentation. Figure 5.1 shows some of what Datalink can do.

Figure 5.1

The additional way in which the scratchpad is used is by not only applying the route to destination, but also alternates; by default, it identifies the primary alternates, but if a different alternate is wanted, pilots can type the ICAO code of that airport into the scratchpad prior to the request, and the ground system will respond appropriately. Also, for example, if there is a typo in the flight number, the crew, will be sent a text notice that the OFP or the route doesn’t exist. At the same time, the timer in the FMS (Flight Management System) will be reset so that they can repeat the request with the fixed values immediately.

An additional thing that Vueling has done in phase one is sending the performance uplink, so that whenever NAVlink service receives the information from the aircraft that the route has been inserted, they can respond with the performance uplink, which includes the idle factor and performance factor. The reason for that is that the business case for the whole project was pretty much based around the optimization and descent, which requires great winds and idle factor. By the performance uplink, the airline makes sure that they have the optimized idle factor on every single flight.

The last element in phase one was that the NAVlink service was responding to wind requests from the flight management system covering all the phases, which was replacing the manual effort by the flight crew. Before that, Vueling pilots manually entered the wind data from the operational flight plan or the in-flight updates received via ACARS to the printer or MCDU (Multifunction Control and Display Unit).

Phase 2

At this point, we realized that even though the way that pilots could load winds into FMS had been simplified, only 50% of flights were requesting winds, which was a problem for the business case. We had to increase the rate of wind uplink requests. NAV and Vueling did some brainstorming and came up with a fairly simple solution as you can see in figure 5.2.

Figure 5.2

Whenever NAVlink service receives the information that the route has been inserted by the pilots, they not only send the performance uplink, but also the wind uplink. The reason is that the flight plan was sent only a few seconds before, so all the waypoints are known as well as the vertical profile and so on. The information from the wind request from the flight management system is not needed. Additional information that is sent in the performance uplink is the cost index, initial cruising altitude and the temperature, a very important one, especially for aircraft types that are thrust limited. Not every pilot would insert actual temperature at TOC, and it’s critical for the optimum and maximum recommended calculations by the FMS on the ground and during climb. A further additional feature is that we are now sending wind updates just prior to descent, leveraging the fact that we may have a newer forecast available than at the time of the pre-flight request. The last enhancement was actually a pretty complex one; it’s the additional uplink of the runway and departure procedures together with the routes.

Phase 3

This latest phase, is already tested and entered into service in January 2025, as you will see in figure 5.3.

Figure 5.3

For upgrades, there is the operational flight plan version check; the airline realized that sometimes pilots don’t have the connectivity in EFB, so they don’t have the latest and up to date documentation. That means that they would be requesting an older route. Now, as a safety net, the system will notify them if they didn’t request the latest route. The additional enhancement is that we worked a little bit more on the consistency of SIDs (Standard Instrument Departures) for alternates. It’s not that it’s difficult or different to send route to destination or alternate, but it was mainly around getting the information from the flight planning system. NAVlink also added winds to alternates, which further reduced the effort for pilots. Ultimately, and super important, is that Vueling has started sending zero fuel weight to pilots with CG (Center of Gravity), block fuel and so on. If you recall what we stated about the previous phases, in phase three, when the pilot sends the initiating request, in a few seconds, s/he will receive all the data to the FMS that allows the calculation of the fuel and time predictions for both trip and alternates which greatly reduces time on ground. And pilots can focus on what’s really important.

USING NAVLINK

Looking at the practicalities of using the solution, first, the pilot requests the information from the aircraft. This request goes through the ACARS message solution to NAV. The airline also forwards information from OFPs so that, when the request arrives to NAV, they have all the information to match it and send back to the aircraft, in just a matter of seconds, the information from the flight plans and wind. it has been working really well for Vueling with NAV providing consultancy , testing and valuable recommendations to Vueling that have been beneficial in the short and long term.

CHALLENGES AND LESSONS LEARNED

As with any such project, not everything went smoothly. For instance, with the AOC data link, it’s often a case of trial and error, and there are two main reasons for that as you’ll see in figure 6.

Figure 6

First, each FMS is unique; they don’t always follow the standards. As readers will know, there are differences between different versions and different OEMs, and then there is the AMI configuration, which again increases complexity. So, the challenges faced included: what parts of the uplink are mandatory? The units used – even though there are metric units in the FMS, the cost index might be in imperial units in certain configurations. Close cooperation between NAV and Vueling was essential, because everything had to be tested for all the possible configurations that the airline operates.

The additional big topic is the navigational database. New problems can arise with a new destination in the route structure. They can also arise with a new AIRAC cycle; there might be a discrepancy between coordinates that creates a discontinuity in the uplinked route, as you can see on one of the screenshots. This is, for example, something that NAV cannot detect on the ground, so they rely on feedback from the customer and, if NAV on the other hand was not very responsive, the feedback from customer would soon stop. Again, stressing out that cooperation between supplier and customer/user is super critical in this kind of service. As we all know, the names in the flight planning and the FMS worlds are different. The FMS identifiers are shorter, so there is no simple way to match them. NAV, with Vueling, has run a lot of ideation sessions, a lot of testing, and has come up with a lot of exceptions, and that works fairly well.

In general, as a takeaway from figure 6, it indicates that, if you stop working like vendor and customer, the classic relationship, and you are more like partners, one team, it will enable you to achieve much more, both in terms of the function that you can get and, of course, also the quality of the service.

BENEFITS

Looking from the pilot’s perspective, Vueling’s vision is to reduce pilot workload at every turnaround which has been reduced, on average, by ten minutes. Vueling is a largely short haul operator, with flights to the Balearics, but also serving longer destinations such as Africa and Iceland in the peak summer season, where every minute saved matters.

Flight crews are no longer manually typing in all the points of the routes and more, there is more time to have weather reports to discuss the contingencies of the route and to and to focus on more critical tasks. focus on situational awareness, ,. As a result, the overall turnaround is more predictable and more consistent, regardless of the pilot experience or the external pressures during the turnaround.

Vueling is gaining flexibility, as illustrated by an issue Jasone had two weeks ago when flying from Malaga, in the South of Spain, to Barcelona. It was ten minutes to closing the doors and she requested ATC (Air Traffic Control) clearance. The ATC replied with a slot of half an hour. So, the dispatcher sold the slot, rerouted the flight and managed to avoid the ATC that was congested, and had the ATC capacity slot. The new OFP was uploaded in 20 seconds. This has improved punctuality and customer satisfaction, because some delays are avoided.

Using the new solution has also reduced maintenance tasks because, in the past, Vueling required a technician to go to every aircraft twice a year, to change the idle and the performance factor with a technician on board. Now, they are uploaded together with the uplink on the FMS. That has saved 450 hours a year on maintenance, and enhanced aircraft availability because, if the aircraft is not in maintenance, it’s flying.

Pilots have also seen that there are more precise FMS calculations, because the solution is uploading the winds on cruise and descent. It allows the aircraft to calculate all the speeds and constraints. Pilots have also seen that, using managed descent with winds, they’re saving approximately 20 kilograms of fuel per flight. In fact, if they’re using the selected mode versus the managed mode with winds, it’s almost 60 kilograms per flight, which is roughly two million a year saving across the fleet as well as saving CO₂ emissions, which means less fuel burn and less taxes. Plus, it supports the airline’s green policies.

Last but not least, pilots appreciate not having to perform extensive manual work on board. They can be more focused on critical tasks, as already stated, and in reply to the airline’s survey, 99% of flight crews are really happy with this implementation. They feel supported and that the company cares about them.

LOOKING TO THE FUTURE AND CONCLUSION

NAV Flight Services together with Vueling are continuously assessing what they can do to improve, what are the operational needs, what is technically feasible. The aim is that, whatever the pilot currently enters manually from paper documentation or EFBs, that should be ideally sent via the AOC data link.

In the cloud, in figure 7, there are a few promising ideas NAV and Vueling have had although they hadn’t checked the feasibility at the time of presentation.

Figure 7

The next logical step seems to be integration with additional systems. So not only connecting to the flight planning, but maybe additional EFB applications like Weight & Balance, take-off data and more.

We hope that readers have found our case study interesting and, if they are planning a similar project, useful.