Robert Clifton Burns, an international business lawyer with Powell Goldstein in Washington, D.C., speculated on his ExportLaw blog Friday that the reason the fine may have been so low is that instrument landing systems are a key component of aviation safety.

U.S. sanctions against Iran, he wrote, "have been severely criticized for their detrimental impact on aviation safety and have been argued to have played a role in a recent civilian air disaster in Iran."

Burns also noted that only rarely does the Bureau of Industry and Security impose fines in the six- or seven-figure range, reserving such penalties "for the most egregious cases."