Telstra says the outage that stopped 604 calls from accessing triple-0 services could have been avoided, blaming the lack of a software update on their timekeeping system and an undocumented design change. The company produced a publicly available submission ahead of chief executive Vicki Brady’s appearance at a Senate inquiry into the failure.Telstra conceded that if “the software update had been completed or had the design change been properly reviewed and documented … the outage may not have occurred”. The submission explained their timekeeping system had been set to “2006” after maintenance work was completed. “Over the next few hours, the incorrect date rippled slowly across the network, causing authentication certificates for software in other servers to become invalid. This affected voice calls and data across Telstra’s mobile network, including calls to triple zero,” Telstra said.The company pointed to various issues which led to the nationwide outage. On 8 July, the technical team executed a standard maintenance update on a network time protocol server, however when the device was powered back on an internal GPS card failed to operate “as expected”. The network time protocol server acts as a time keeping device, yet when the GPS failed the year was set to 2006. “This affected voice calls and data across Telstra’s mobile network, including calls to Triple Zero,” the submission explained. The outage could not be pinpointed to a single error as the company explained the GPS issue was the result of a previous intentional design change which had not been properly documented. The submission also claimed “a (necessary) software update had also not been applied to the device”. ‘Telstra let Australians down’In her opening remarks to Friday’s inquiry, Ms Brady was apologetic and vowed transparency as Telstra continues to probe the outage.“Last week, Telstra let Australians down,” she said.“We let our customers down, we let the community down, and we fell short of what people rightly expect from us -- for this I am deeply sorry.“Australians rely on Telstra every day to run businesses, stay in contact with family, access essential services, and most importantly, to get help in an emergency.“When our network fails, the impact is real.”Speaking to the triple-0 outage specifically, she said triple-0 “sits at the heart of public trust in Australia’s communication system”.“Telstra has a critical role in that system, and we take that responsibility extremely seriously,” Ms Brady said.“No one should be left wondering whether a call for emergency help will get through.”More to come