A passenger booked on a 7:20 p.m. flight from Brasilia to Confins airport, in Belo Horizonte, told TV Globo that boarding had not even started at departure time. On Tuesday evening (22), the boards at Brasilia International Airport Juscelino Kubitschek listed Azul flights as "cancelled". By 8:30 p.m., hundreds of people were queuing at the airline's counters with no word on whether they would fly that night or on another day, according to news site g1.

The cause was far from the check-in desk. In a statement released in the early evening, Azul, one of Brazil's largest airlines, said an "instability in the global GPS system" was affecting the operation of its Embraer E2 fleet, built by Embraer, the Brazilian planemaker.

"As a precaution, the company is adopting operational measures that may result in adjustments to the network and to the schedule of some flights. The company advises customers with impacted flights to check the status of their reservation on official channels before going to the airport."

How big the problem is

According to Folha de S.Paulo, citing the specialized aviation website Aeroin, nearly all of the E195-E2 jets flown by Azul lost GPS signal reception on Tuesday afternoon. At 5:30 p.m., only two were in the air, one bound for Recife and one for Porto Alegre, both having left São Paulo. The other 43 aircraft of the model never took off. At Congonhas airport in São Paulo, the boards showed three cancelled flights by late afternoon, two to Belo Horizonte and one to Curitiba, plus one delay to Rio de Janeiro.

The fix is the manufacturer's responsibility. An Embraer communiqué relayed by pilots, which Folha had access to, confirms reports of GPS loss on several E2 aircraft from different operators and says the failure leaves a plane unavailable to fly. Embraer said it is investigating the fault together with Honeywell, the company behind the system, to determine the cause and its extent. Contacted by g1 and Folha, Embraer had not responded by publication time. g1 also asked Inframerica, the company that runs Brasilia's airport, for a tally of affected flights and received no reply.

Brazil's other major carriers say they are unaffected. Latam, which has Embraer jets on order, said it recorded no abnormality because those planes only join its fleet in December. Gol said it does not operate the E2 line.

What passengers should do

• Before heading to the airport, check your reservation status on Azul's official channels, such as its website and app. The recommendation comes from the airline itself.
• Passengers with affected flights are receiving the assistance set out in Resolution 400 of Anac, the rule of Brazil's civil aviation regulator that defines passenger rights in delays and cancellations.
• Azul ground staff in Brasilia told one passenger that some flights would be moved to Latam, but that not every destination and passenger could be handled that way.