Indonesian authorities have grounded nine airlines, which failed to improve their safety record, the transport ministry said on Tuesday.
Four airlines had their operating licenses revoked and five other small airlines were suspended for failing to improve their safety in the past three months, an official at the air transport directorate-general's office said.
"The air operating license of Jatayu Gelang Sejahtera has been revoked after it failed to meet minimum safety regulations," the official, who identified herself as Fitri, told AFP.
She said this was the largest company to lose its license among four. The others were Aviasi Upataraksa, Alfa Trans Dirgantara and Prodexim, which have aircraft that carry fewer than 30 passengers.Fitri said authorities had also suspended the licenses of five other small airlines, all with planes seating fewer than 30 passengers, and given them three months to improve their safety standards.
These were Germania Trisila Air, Atlas Delta Setia, Survey Udara Penas, Kura-kura Aviation and SMAC.
The groundings follow the transport ministry's latest quarterly review of airline safety and comes after a series of accidents in Indonesia's rapidly growing airline industry.
Flag carrier Garuda Indonesia -- one of whose airplanes crashed in March, killing 22 people has improved its safety standards and is now ranked alone in the top category after being upgraded a tier, Fitri said.
Seven other companies were upgraded from the third and lowest category in the scale to the second, including Adam Air, which lost a jetliner on New Year's day this year with 102 people on board.
The plane is believed to have smashed into the sea and the wreck has never been recovered.A dozen other airlines, including state-owned Merpati Nusantara, and the Indonesian subsidiary of Air Asia, remain in category two, Fitri said.
Authorities in March said after their survey that none of 20 airlines operating with capacities of more than 30 passengers were in the top safety category, and seven were in the bottom.
The seven were given three months to improve their safety rating or face closure.
Indonesia's airline industry was deregulated in the 1990s, encouraging many new operators to take to the skies and producing massive passenger growth, but the recent disasters and other accidents have raised fears of lax safety.
Experts have blamed old planes, poor standards and insufficient investment in infrastructure.