Read Text IV and answer the question that follow it.
TEXT IV
Flights resume in Sao Paulo after
brief airspace closure due to technical issue
SAO PAULO, April 9 (Reuters) - The airspace of Sao Paulo has
been reopened following a brief closure on Thursday morning,
the Congonhas and Guarulhos airports' operators and the
Brazilian Air Force said in separate statements.
Operators for the local Congonhas Airport and Guarulhos
International Airport had said earlier that all landings and
takeoffs had been suspended in the city due to what the
Congonhas' operator said was an "electrical failure."
Brazil's Air Force, which is responsible for national air traffic,
said the suspension lasted just over half an hour, adding it found
a "technical operational issue" as the reason for the incident,
without providing further details.
Guarulhos' operator said the issue did not happen at its
airport, the busiest in Latin America.
As operators rushed to mitigate the impacts, Brazil's civil
aviation regulator said it implemented a series of initial measures
outlined in its pre-crisis protocol, with the aim of monitoring the
consequences of the incident.