The FAA says recent evaluations of error reports occurring over oceanic airspace show that deviations, especially vertical large height deviations (LHD), have increased in numbers to the point where they exceed the agency’s safety target levels. That means increased risk for both private and commercial operators. An LHD occurs when an aircraft strays more than 300 feet from its assigned altitude. Data collected from a variety of ATC service providers indicates that a “majority of crew errors center on misinterpretation of conditional clearances,” normally used to locate the most efficient cruising altitudes. To help mitigate these and other LHD problems, the FAA has produced safety alert for operators No. 13004. The International Civil Aviation Organization already produces an oceanic errors safety bulletin, which looks closely at the operational issues that crews should be focusing on in the near term, as well as standard operating procedures, best practices and safety controls and mitigations that might well be included in an operator’s international operations training program. Both publications focus on the positive safety impact of strategic lateral offset procedures, which suggest that aircraft operate one or two miles to the right of the course centerline to prevent a head-on collision in case an opposite-direction aircraft is flying at the wrong altitude.