Bankruptcy laws differ in each country.
In Latin America, I am afraid it is standard practice from time to time. Mexicana itself failed financially in 1968, reorganised and recovered, failed again in 1995, this time they were nationalised, got returned to the private sector in 2005 - and here we are today.
Aeromexico, the other Mexican major, has a similar history, bankrupt in 1988, recovered, and had to be renationalised in 1995, now private again.