# How one line of code caused a $60 million loss

DevFeed: [How one line of code caused a $60 million loss](<https://devfeed.tech/articles/how-one-line-of-code-caused-a-60-million-loss-39091.md>)

Original publisher: [Read original article](<https://read.engineerscodex.com/p/how-one-line-of-code-caused-a-60>)

Author: Engineer's Codex

Published: 2023-11-13T07:08:08Z

Content type: article

Language: en

Sources: [Engineer's Codex](<https://devfeed.tech/sources/engineer-s-codex.md>)

Topics: [bug](<https://devfeed.tech/topics/bug.md>), [Code](<https://devfeed.tech/topics/code.md>), [Software Engineering](<https://devfeed.tech/topics/software-engineering.md>), [C](<https://devfeed.tech/topics/c.md>), [incident](<https://devfeed.tech/topics/incident.md>), [Testing](<https://devfeed.tech/topics/testing.md>), [networking](<https://devfeed.tech/topics/networking.md>)

Tags: [bug](<https://devfeed.tech/tags/bug.md>), [c](<https://devfeed.tech/tags/c.md>), [code](<https://devfeed.tech/tags/code.md>), [incident](<https://devfeed.tech/tags/incident.md>), [networking](<https://devfeed.tech/tags/networking.md>), [routing](<https://devfeed.tech/tags/routing.md>), [software-bug](<https://devfeed.tech/tags/software-bug.md>), [software-engineering](<https://devfeed.tech/tags/software-engineering.md>), [testing](<https://devfeed.tech/tags/testing.md>)

## AI overview

This article examines how a software bug in a C program used in AT&T's telephone network caused a cascading outage in January 1990. The incident disrupted phone service, delayed airline flights, and caused substantial financial losses.

## Source excerpt

60,000 people lost full phone service, half of AT&T's network was down, and 500 airline flights were delayed