July 29, 2015
Aeronautical chart maker Jeppesen is rolling out a new way to depict Aerodrome Operating Minimums on its library of instrument approach procedures charts, a change that will significantly affect pilots who fly outside of the United States.
At issue is the availability of aerodrome operating minima (AOM) and how those minima are depicted in charts of other countries’ airspace. Many nations, such as the U.S., publish complete AOM for their instrument approaches. However, other countries provide only partial AOM or no AOM at all for their approaches. In these cases, Jeppesen had published AOM data using accepted standards, largely based on United States’ standard for terminal instrument procedures. However, that has changed due to recent international efforts.
“Where the state-provided AOM is complete, including a decision altitude (DA) or a minimum descent altitude (MDA), Jeppesen will publish that,” said Rich Boll, chairman of the NBAA Access Committee’s Flight Technologies Working Group. “However, where that information is incomplete or not available, Jeppesen will publish AOM based on the International Civil Aviation Organization’s new all-weather operating minimums.”
“Since 2009, there’s been a push to establish new AOM in Europe that favor the use of a constant descent final approach (CDFA),” Boll explained. “The idea has been to discourage the ‘dive and drive’ final approach by imposing higher visibility minima when compared to using CDFA.” As a result, operators will see two separate sets of visibility minima, one for CDFA and one without CDFA.
“Operators in the United States will see little change to what we have now,” said Boll. But he was quick to point to the Caribbean, where some of the changes mandated in Europe will also take effect.”
Operators may also see a new descent limit, DA/MDA(H) on approaches where a vertical descent angle (VDA) is published supporting CDFA. If the DA/MDA(H) does not include a height adjustment accounting for the altitude loss associated with a missed approach using CDFA, Jeppesen adds a note stating that use of DA(H) in lieu of MDA(H) requires a height adjustment, which could add 50 to 100 feet to the published DA/MDA(H).
Finally, Jeppesen is updating the profile view of its instrument approach charts, indicating when a VDA is published and CDFA is mandatory, when it is optional, and when a VDA is not published and a “dive and drive” approach with level segments is required.