It’s 8:30 p.m. Eastern Standard Time on a November evening as a student pilot plans a solo cross-country flight for the coming weekend. Converted to 24-hour clock time, it is 20:30, and converted further to coordinated universal time (UTC), or Zulu time, by adding five hours, the time is 0130Z.
But the calculation isn’t complete. After making the conversion of hours and minutes from local time to Zulu time, the date also needs tweaking. For example, if it is 8:30 p.m. EST in Boston on Nov. 30, it is 0130Z on Dec. 1 because adding five hours to the local time takes the conversion beyond midnight UTC.
Still, the conversions take practice, and if there is one error pilots make that has been put in the spotlight by aviation authorities in the United States and Canada, it is forgetting to use the correct date when a time conversion crosses 0000Z.
But it’s not just pilots who must sharpen their focus figuring out the correct time and date. “Since 2011, minor changes have been introduced to clarify time periods; however, periods spanning midnight are still generally misinterpreted. It is crucial for users and NOTAM Originators to read or compose these schedules correctly, since a misinterpretation could result in an aeronautical incident or accident,” says an Aeronautical Information Circular issued by Nav Canada in October.
The FAA is also focused on the issue as part of a wider initiative to make notams easier to find and read using information-screening filters on the Notam Search website.
An FAA task force’s goal “is to improve notam policy, management, and training and to jointly address changes that will improve timely notam coordination and dissemination," said Lynette M. McSpadden, a U.S. Notam Governance and Operations senior specialist.
“Helping pilots understand the time periods of notams has been part of that effort,” said Rune Duke, AOPA director of airspace and air traffic.
One product of the effort has been production of an online course for pilots offering a refresher on notams. The course, "Notam 101, Back to Basics," is available on the FAA Safety team’s website.
Would you benefit from such training? Don’t underestimate the hazards of having a weak understanding of time-period terminology used in notams.
“Interpreting time periods is one of the most critical aspects of reading a notam,” said Caroline Doucet, Nav Canada’s manager of Aeronautical Information Management, Standards and Procedures. “This could mean the difference between operating in uncontrolled airspace and operating in an active restricted airspace.”
“Occasionally, a flight plan is filed through an active restricted airspace despite a notam being in place. As a result, controllers have to reroute such flights,” she added.