Tcorr Inspection understands the importance of the correct application of aircraft coatings, from the surface preparation of the aircraft substrate for maximum coating adhesion to the application of the final topcoat to prevent the formation of corrosion through the penetration of moisture to the aluminium substrate.
If applied correctly, an aircraft protective paint coating should be expected to see a life span of at least 8 to 10 years. However, in most cases, the paint coatings are lucky to see a service life of 5 years due to incorrect application procedures.
For a small cost, Tcorr Inspection can monitor your staff / contractors’ progress to ensure the coatings are applied properly ensuring you can achieve maximum life span of the coating and in turn reduce maintenance costing blowout on unnecessary hangar downtime.
All inspections are carried out in accordance with Military Specifications MIL-PRF, the coating manufacturers’ guidelines and as set out in the applicable maintenance manuals.
Effect of Coatings on Flying Efficiency
The key factor with drag is air flowing over the airframe. Consequently, the critical consideration for aircraft coatings is the smoothness of surface finish achieved by the topcoat. The effect can be considerable and led to Boeing’s decision, for example, to use only one paint colour on the engine nacelle inlet of the latest 787 Dreamliner. Boeing found that the tiny edge created where one colour is laid over another affected airflow to such an extent that using only one paint colour could save as much as 22,000 gallons (more than 100,000 litres) of fuel per year. If that is accrued over the expected lifetime of the aircraft, it creates savings of 880,000 gallons (or 4 million litres) per aircraft.
The accumulated weight of coatings can also be significant. For example, the coating’s dry-weight on the exterior of the Airbus A380 is approximately 1,600 pounds (725 kgs) compared to the exterior coating’s dry-weight on a Boeing 747 of approximately 1,060 pounds (480 kgs). Typically, the exterior coatings on these aircraft consist of an epoxy primer, high solids topcoat, separate wing coating and a small quantity of area-specific coatings. The interior structural coatings can add a further 1,600 pounds (725 kgs). This gives a total coating dry-weight on the aircraft of around 4,260 lbs (1,930 kgs) that has to be overcome by lift. Any reduction in weight that does not affect coating functionality will have an accumulating cost benefit.
As a general guide, every kilogram of weight removed from a commercial jet aircraft will save around 25 gallons of fuel per annum.
Tcorr Inspection will ensure that your staff / contractors have achieved the correct coating thickness in accordance with the relevant Australian Standards, which is a DFT (Dry Film Thickness) of 20 ±5µm for polyurethane primer and DFT 50 ±10µm for the polyurethane finishing paint.