On March 8, 2017, nearly all AT&T Mobility (AT&T) Voice over LTE customers across the nation lost 911 service for 5 hours. This was one of the largest 911 outages ever reported in the Network Outage Reporting System (NORS), as measured by the number of unique users affected.

Federal Communications Commission Chairman Ajit Pai immediately directed the Public Safety and Homeland Security Bureau to investigate the causes, effects, and implications of the outage. In response, the Bureau reviewed and analyzed outage reports filed in NORS, as well as sought and reviewed public comments and related documents, and held meetings with relevant stakeholders, including service providers and public safety entities. The Bureau also examined the record to identify ways to prevent future occurrences of such an outage. This report presents the Bureau’s findings.

The outage was caused by an error that likely could have been avoided had AT&T implemented additional checks (e.g., followed certain network reliability best practices) with respect to their critical 911 network assets. Approximately 12,600 unique users attempted to call 911, but were unable to reach emergency services through the traditional 911 network.

Among the lessons learned from the March 8 outage is that when 911 service fails for any reason, Public Safety Answering Points (PSAPs) play a critical role in advising their jurisdictions of alternative ways to reach help. While AT&T and their subcontractors, Comtech and West, made efforts to notify thousands of PSAPs, the notifications were often unclear or missing important information, and generally took a few hours to occur.

This outage also offers an illuminating case study that illustrates actions that stakeholders can take to promote network reliability and continued access to 911 service. Read the report here: AT&T VoLTE 911 Outage Report and Recommendations.