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Aviation ground operations – Lean or not Lean?

Date: / Category: News China / By:
Andrea Hoefer, Project Manager, STAUFEN.SHANGHAI

Andrea Hoefer, Project Manager, STAUFEN.SHANGHAI

When asking ground handling providers around the world whether they would consider their operations as Lean, many of them would probably quite promptly reply and state that, of course, they are.

Being recognized as an industry which turns around aircraft within astonishingly short time windows, processes must, obviously, be Lean – how else would you be able to deboard, unload and reload bags and catering, clean, fuel, change crews and board an 150er seater within 35 minutes? Sounds convincing. If taking turnaround times as sole evaluation criterion, the before reasoning is quite incontestable. However, when challenging this reasoning and when questioning what is the cost of making the impossible possible, one might find that ground handling operations are not so Lean after all.

Ground handling, or that part of the aviation industry, which is responsible both for servicing aircraft between arrival and departure and for handling passengers, baggage and cargo, is a highly time-crucial business. Whether ground handling is provided by airports, airlines or independent companies (the latter already being the predominant kind of provider in most parts of the world), they all face the same challenge: from the moment an aircraft is on blocks, the time to departure is inexorably counting down – not to mention it usually is a very short one, too. In their attempt to maximize aircraft utilization, airline planners intentionally keep scheduled ground times to a minimum and, if at all, add only a few minutes of buffer to allow for minor unplanned occurrences on the day of operation.

Thus, well-aware that any irregularity of individual processes is likely to have immediate repercussions on other processes, and, at the worst, on entire airline networks, all parties involved in the turnaround of an aircraft will try their utmost to avoid deviations from planned operations. In fact, on-time departure is the most important objective on the day of operation (outreached only, and understandably, by the aspect of safety and security), with every delay being meticulously followed up and assigned to the responsible party.

Consequently, with such a pedantic but necessary focus on punctuality, it is self-evident, that processes are designed in a way, that even operations with minimum ground times can be handled on-time. For instance, consider the following simplified turnaround. Upon aircraft on-blocks, passenger arrival busses are readily available to ensure timely deboarding. While the last remaining passengers are still disembarking via the front stairs, the cleaning team has already gone aboard via the aircraft’s rear door. Meanwhile bags are being offloaded and delivered to the respective arrival belts in the terminal. Outbound baggage has been sorted and is being brought on position to be loaded once unloading is finished. In between all this, the aircraft is being refueled and provided with new catering. As soon as all major onboard preparations are met, the cabin crew will have the gate staff commence boarding. Two busses take the passengers on position. Few minutes later, boarding is completed and the aircraft is ready to go off blocks.

At first sight, the above set of processes appears to be perfectly Lean. In order to do a full turnaround in the given amount of time, all activities are well aligned and, wherever possible, synchronized. Value-adding activities are by far outweighing non-value adding activities. Standardization of processes and the definition of clear roles and responsibilities are a matter of course, the latter of which being especially important due to the high number of different parties involved in a single turnaround.

However, saying that aviation ground operations are Lean, just because those processes directly concerned with the turnaround itself are efficient, would neglect other fundamental principles of the Lean idea. In fact, performing efficient turnarounds within increasingly short ground times is only one side of the coin. Rather than merely considering the turnaround itself, it is paramount to bear in mind the entire value stream. And even if taking a closer look only at immediate upstream and downstream processes, the picture of aviation ground operations being Lean fades. 

When reconsidering the previously described turnaround, just challenge the prompt availability of passenger busses upon arrival. For sure, in the majority of cases, these resources do not arrive just in time; instead they are likely to wait several minutes before they are actually required. The same typically applies to passenger departure busses. They oftentimes spend a lot of time outside the terminal waiting for boarding to begin and the first passengers to get on the bus; and, once on position, waiting again before passengers are allowed to get off the bus. Similar situations come up for other resources just as well. On the basis of a single turnaround, such waiting times might be neglectable but looking at them from a wider perspective, they do have quite an impact. 

With airports, especially bigger ones, having large numbers of aircraft on ground at the same time, binding resources on one position will automatically make them unavailable on other ones, which from an optimized planning perspective, results in overcapacity. Those waiting times add up, both in the short-term and the long-term, and might influence major decision-making.

Even more importantly, some of them have a tremendous impact on passenger experiences. Waiting during boarding procedures – whether at the gate itself, in boarding bridges, or busses – is not the only situation where a passenger’s patience is challenged. From check-in, via security check to passport control and boarding, passengers usually find themselves standing in line together with hundreds of other travelers. Rather than being handled according to the production-related concept of one-piece flow, passengers are queued up at various process stations, resulting in the ratio of waiting time over presence time usually being many times more than the ratio of process time over presence time (see Figure 1).

Figure 1: Break-down of the passenger departure value stream into process time and transition time (example)

Scheduled ground times in aviation have become increasingly short. On the day of operation, a considerable number of interrelated and interdependent processes needs to be well aligned for them to be successfully squeezed into an aircraft turnaround. Buffers to compensate for unexpected occurrences are few, while pressure for on-time performance is high. Hence, any inefficiencies have been shifted outside the actual turnaround, making aircraft ground times themselves appear quite Lean. However, it is the entire value stream which needs to be taken into consideration in order for a system to be deemed truly Lean. So far, the cost of an airlines’ efficient turnarounds is passed on to their service providers and, paradoxically, to their passengers. One of the most fundamental principles of Lean, though, comprises the objective to always put the end customer in the focus of any operation. In aviation ground operations, all too often, attention is centered around the aircraft value stream, losing sight of the fact that the passenger value stream is actually equally important.