American Airlines issues ground stop for all flights due to 'communications issue'

Major U.S. carrier American Airlines issued a ground stop for all its flights early on Friday due to a communication issue, according to the U.S. Federal Aviation Administration's status page.

American Airlines did not immediately respond to Reuters' request for a comment on the ground stop.

But customers travelling with the carrier said on social media their pilots had told them that all systems were down and that all aircraft must remain grounded until they are brought back online.

Many complained they had been left stranded in planes sitting on the tarmac before take-off or after landing at their destination. 

It comes hours after the operations of several low-cost carriers, including Frontier, were affected on Wednesday and into Thursday due to a Microsoft cloud outage. 

Microsoft said on Thursday it was investigating issues with its cloud services in the Central U.S. region, which had caused the grounding and cancellation of several flights.

Carriers Frontier, Allegiant and SunCountry reported outages that affected operations.

While Frontier said a 'major Microsoft technical outage' had hit its operations temporarily, SunCountry said a third-party vendor affected its booking and check-in facilities, without naming the company.

'The Allegiant website is currently unavailable due to the Microsoft Azure issue,' Nevada-based Allegiant said in a statement to CNN. Allegiant did not immediately respond to Reuters request for a comment.

Frontier cancelled 147 flights on Thursday and delayed 212 others, according to data tracker FlightAware. 45% of Allegiant aircrafts were delayed, while Sun Country delayed 23% flights, the data showed. 

The companies did not give details on the number of flights impacted.

Microsoft said its outage started at about 6 pm ET on Thursday, with a subset of its customers experiencing issues with multiple Azure services in the Central US region.

Azure is a cloud computing platform that provides services for building, deploying, and managing applications and services.

Separately, Microsoft said it was investigating an issue impacting various Microsoft 365 apps and services.

Microsoft did not immediately respond to a Reuters request seeking further details on the outage

Other operators that were affected included Allegiant and SunCountry. 

Microsoft said that its Azure cloud software had suffered a temporary failure which triggered a breakdown in 'service management operations and connectivity or availability of services' across the central US region. 

However, the outage did not impact American Airlines, it said earlier in a statement to Reuters, suggesting that carrier had suffered a separate issue.