The trend threatens to erode higher standards established during what one analyst called a "tremendous amount of soul searching" by major carriers and the government after 2007, when frequent crashes prompted the European Union to ban all Indonesian airlines from landing on its runways for two years.
With growth rates of nearly 20 percent per year, Indonesia is one of Asia's most rapidly expanding airline markets, but the country is struggling to provide qualified pilots, mechanics, air traffic controllers and updated airport technology to ensure safety. And with so many new, small carriers, it's hard to monitor all their standards.
"We are not ready for this boom," said Ruth Simatupang, an Indonesian aviation consultant and former safety investigator.
Just how fast Indonesia's airline market is growing came under a spotlight with Wednesday's deadly crash of a Sukhoi Superjet-100 plane during a demonstration flight. While both the plane and the pilot were Russian, the flight was packed with representatives of local airlines that the manufacturer hoped would purchase the jetliner.
The number of air passengers in Indonesia jumped by 10 million in a year to 53 million in 2010, according to the government statistics agency, and the upward trend continued last year.
"Infrastructure hasn't kept pace with the growth of the airlines," said Shukor Yusof, an aviation analyst in Singapore for Standard & Poors.
In the past five years, Indonesia has added 36 new passenger and cargo airlines, bringing the total to 86 -- many of them small carriers serving outlying islands where the only travel alternatives are ferries.
Feeding the demand for new air routes are Indonesia's population of 240 million, its geography of 18,000 islands and an economy that grew at a 6.5 percent clip last year, creating a larger middle class eager to travel.
"Indonesia is a natural market for growth," said Brendan Sobie, chief Southeast Asia representative for the Centre for Asia Pacific Aviation. "It's one of the world's biggest populations and one of the world's most underserved markets for airlines."
Transportation official Herry Bakti Singayuda insists that Indonesia's rapid airline growth is still compatible with safety.
"We evaluate the operators," said Singayuda, who directs the Air Transport Department under the Ministry of Transportation. "We control that growth based on their capability, their facilities and personnel."
He added that the government has expanded flight schools, hired new inspectors and added 10 regional offices to keep up with the new airlines.
Yusof agrees the government and major carriers have markedly improved safety standards in the five years since the EU blacklist, which followed fatal crashes by Garuda and now-defunct Adam Air in 2007.
The government responded with a raft of new regulations and training schools, while Garuda invested millions of dollars to train staff and upgrade its fleet. Lion Air, which recently placed the largest-ever order for Boeing aircraft -- 230 planes listed at some $22 billion -- has also sought to improve safety, though it took a blow when several of its pilots were arrested in recent months with illicit drugs.
"Garuda and Lion Air have done a tremendous amount of soul searching in terms of safety and in bringing in experts ... to help them clean up their act," Yusof said. The newer airlines, however, may need more scrutiny.
Smaller airlines serving the domestic market may have less money to invest in training and hiring qualified pilots and mechanics, said Simatupang, the Indonesian aviation consultant.
"There are a lot of new pilots whose flying hours don't meet the minimum standards, but because the operators need them, they use them sometimes," she said.
Like Yusof, Simatupang called on the government to do more to regulate the new airlines.
"I always say to the government, please do the new infrastructure and safety regulations first," she said. "And then allow the airlines to expand."
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