Studying corrosion levels at RNZAF airbases
"Time at high humidity and ambient temperatures is ideal for corrosion."
- Corrosion mass loss across Whenuapai, Ohakea and Devonport is roughly equivalent.
- The corrosion of hangered aircraft was below detection limits, even on HMNZS Otago.
- Salt contaminated airframes in hangars at high humidity will corrode so regular and effective cleaning is important.
Due to the nature of RNZAF operational requirements, airplanes spend a significant portion of their time on the ground awaiting use. This time at high humidity and ambient temperatures are ideal for corrosion.
To study the corrosion levels at airbases we installed specimens in both hangars and the outdoors and measured the mass loss over a period of 3 months.
Key variables for corrosion include:
- length of time a sample is wet due to rain, condensation or high humidity
- airborne salt concentrations
- total particulate level. Particles include mainly salt but also dust which can increase time of wetness by absorbing water when it rains or is humid
- sulphur dioxide concentrations
- other pollutants.
Results showed that the corrosion of hangered aircraft was below detection limits which highlighted the known benefits of storing aircraft in hangars. The results also indicated that a salt-laden aircraft stored in a humid hangar will continue to corrode. This identified that regular aircraft cleaning is necessary and ideally aircraft should have dehumidification when on the ground.
The study also showed that corrosion levels across Ohakea, Whenuapai and the DTA facilities at Devonport were generally comparable and so experimentation at the DTA can be considered relevant for both Ohakea and Whenuapai.