As important components of an aircraft’s primary structure, it’s essential to know about the lifespan of floor panels and their cost-effectiveness. A longer lifespan facilitates the aircraft operators to use the structure over a longer period which reduces the total cost of ownership. How long should floor panels last and what impacts their longevity?
Unfortunately, there’s no easy answer to this question.
The lifetime of a floor panel is determined during the heavy maintenance ‘C’ and ‘D’ checks, conducted every three and six years, respectively, when cabins are removed to reveal damage or during a cabin retrofit. The replacement of a floor panel is assessed based on whether damages exceed the Repair Limits listed in the Structural Repair Manual’s Allowable Damage List.
While we can say that the normal floor panel lifespan for a passenger aircraft should be between 25-30 years and 30-40 years for freight aircraft, there are many varying factors that can impact its lifespan. Its material composition may affect it, for example. But usually, it depends on operational factors – its installation, utilisation and incidents of damage.
Most floor panels have common components, each adding functionality and durability to the overall panel performance.
They are usually made from honeycomb sandwich panels with faces consisting of different pre-impregnated glass and carbon fibres. The amount of this pre-impregnated material and the direction of each layer determines the definition of the panel’s technical properties.
A thermic pressing compounds all the materials with resin, followed by a final deep-frying of the panel. But if the temperature of the resin is not correct in the production process, bubbles will develop in the floor panel. This will impact the connection between the top layers and the honeycomb which can lead to delamination and impact durability.
When it comes to a more robust – and more durable – floor panel, semi-finished floor panels are often a good solution because they are made with a smaller honeycomb composition, providing greater compression and higher impact resistance.
These mechanical properties can all help to prolong the lifespan of floor panels.
Problems that occur at installation of the floor panel will also impact its longevity. For example, edges must be filled with filler to help prevent liquids from getting into the panel structure and reducing its durability. If this is not done properly, issues will occur earlier in the panel’s lifetime, such as disbonding caused by water. An ingress of water over time can actually cause the honeycomb core of a floor panel to dissolve.
Tapes and seals must also be applied at installation, to ensure the floor structure and floor panels are disconnected to avoid galvanic corrosion.
The way the floor panel is used will also influence its lifespan.
And this will often come down to the aircraft zone where the panel is used. There are high-risk areas within the aircraft with accompanying high replacement rates:
For passenger aircraft:
For cargo aircraft:
Lifespan values of floor panels are very much linked to these aircraft operation zones.
Damage will also impact the life expectancy of a floor panel. Different types of damage include delamination, scratches, and holes and indentations caused by dropped objects. They are, however, linked to the installation processes and the environment and not the floor panel per se.
Indentation occurs with the dropping of objects in the wet areas, or even mobile phones in the seat areas. Damage to the cabin area floor panels will result from operating trolleys over a long period of time. Damage to the cargo area floor panels will occur through baggage loading. Impacts can generate a variety of damage to the panel’s core and skins, and its residual strength can be greatly reduced. And as mentioned, improper foiling in the installation phase will cause delamination.
The more robust the floor panel is, therefore, the longer the panel will last. The Airbus semi-finished floor panels, for example, are more robust than their finished counterparts and are expected to be at least twice – if not three times – as enduring. The increased robustness of the floor panel will, of course, cause an increase in aircraft weight. But this is outweighed by the improved coverage offered by the semi-finished product in high-stress load areas. And can be mitigated by balancing of fuel carried on board.
For the same reasons outlined above, it is also difficult to determine the lifespan of a semi-finished floor panel as it will depend on its composition, installation and utilisation.
Without being able to definitively say what the average lifespan of a finished or semi-finished floor panel is, it is also difficult to be conclusive about the total cost of ownership.
But the semi-finished floor panel does add value to airlines needing to replace their panels, simply because three floor panels can be cut from one semi-finished floor panel. And even when the installation cost of semi-finished floor panels is taken into consideration, the Airbus semi-finished products are able to yield three panels for the price of one finished panel.
It’s a matter of finding a competitively priced product that enables several panels to be cut from the one board, together with increased robustness that can guarantee a highly durable and long-lasting product that will seldom be in need of repair or replacement.
The increased robustness of the semi-finished floor panel undoubtedly extends its lifespan, making it a more durable alternative to the finished panel. So, even if it is difficult to gauge just how long a floor panel should last given the various factors impacting it, Airbus’s more robust semi-finished panel will probably ensure increased duration.
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This blog is driven by Satair Marketing & Communication with input from both internal and external contributors.
Satair is a world leading provider of aftermarket services and solutions for the civil aerospace industry. Satair is a stand-alone company and Airbus subsidiary.