Most parts- like fuselage skin, frames and wing structures- of aircraft are made of aluminium alloy. However, this light-weighted material is very vulnerable to environmental attacks such as chloride deposits existing in humid air, and induced stress corrosion due to intensive flight missions. This issue is especially concerned by Taiwanese aviation organizations because of Taiwanese oceanic climate. Two types of corrosion evaluation practices- alternative immersion corrosion test per ASTM-G44 standard; and natural environmental corrosion test- on AA 7075-T73 coupons are investigated in the current study. Two corrosion indexes – the weight loss per area measured after removal of corrosive compounds, and induced equivalent initial flaw size- for both corrosion practices are compared and verified. A predictive equation to assess the fatigue damages of naturally corroded AA7075 has confirmed by comparing with the artificially corroded damage on AA7075 specimens following ASTM-G44 procedure. The findings provide a practical correlation between widespread corrosion damage and estimation of impact to fatigue resistance capacity of aircraft fleets which is what maintenance staffs have always been concerning during their periodical inspections on fighters/commercial aircrafts in all major airports in Taiwan.