Hangar environment monitoring for corrosion risk assessment and aeronautical heritage protection

The paper shows how the aeronautical heritage is affected by airborne pollutants and the air temperature-humidity complex. Monitoring meteorological and environmental data in a heritage site intended for protection, these effects are analyzed. The starting point is thus the acquisition of the meteorological and environmental data from the intended hangar with stored historical aircrafts taken part in fights of the second world war. The following step is an evaluation of the penetration of moisture into the hangar environment from outside. This moisture penetration is deducted from wet/dry cycles obtained from air humidity and temperature fluctuations in the hangar environment. In addition, an evolution of the aircraft surface temperature is pertinent to potential moisturizing the aircraft surface. As a measure of moisture penetration, a time of wetness (ToW) is determined indoors. Furthermore, pollutants infiltrated into the hangar environment are derived from a standardized methodology. Beside the pollution infiltration, the indoor generated pollution is estimated per material from which the historic aircrafts are constituted. Because of major material in the aircraft, the deposition rate of indoor pollutants onto an aluminum alloy is determined by means of a standardized statistical model. Finally, monitoring the hangar environment, the heritage aircraft vulnerability to corrosion is estimated based on atmosphere corrosivity modeling.