The Center for Transportation and Logistics Studies, a private policy group, said Indonesia's discount airlines have increased the amount of time planes spend in the air, from 70 percent to up to 95 percent to boost profit margins, putting a crunch on servicing.
But there is not enough data available to say if that was jeopardizing safety, said Danang Parikesit, a leading researcher, though cost-cutting was "probably reducing the safety standard."
Bansar, one of the former pilots, said there was no doubt in his mind that was the case.
When mandatory aircraft part replacements were due, including essential navigational instruments, Adam Air officials "swapped with another aircraft, so as not to replace it ... then if they didn't find the part for another 30 days, they would swap it again," he claimed.
Banser said he flew on a plane with a cracked door handle "for several months" because there was no spare in stock. He asked an engineer if it was legal to fly with the defect and "he just smiled."
"Every time you flew, you had to fight with the ground staff and the management about all the regulations you had to violate," said Banser, who says he was grounded for a week in 2005 after refusing to fly because he would exceed the maximum of five daily takeoffs.
He said he gave in to demands that he fly the plane - which also had a damaged window - after managers agreed to pay each crew member an additional $110 - an offer Bansar accepted.
But eventually the pilot said he lost faith and quit.
Sudibyo, the aviation expert advising Yudhoyono, recalled a still-unexplained incident last year when one of its Boeing 737s went missing for hours following a navigation and communications breakdown, eventually making an emergency landing in Tambolaka, hundreds of miles from its final destination.
The airline broke several civil aviation regulations that day, including flying the plane away from the scene before an inspection by aviation authorities, he said. The pilot was fired, but government regulators would not say if the airline was fined, citing confidentiality regulations.
"The safety report on that company is a big question mark," Sudibyo said.
Iksan Tatang, Indonesia's top civil aviation official, said he had heard about the accusations, but could not respond in detail until reviewing formal complaints from the pilots.
"I invite the pilots to give me the information. Why did they give it to everybody, but not the regulators?" he asked. "As far as I know, we have to follow the international regulations."
Pilots said they regularly reported maintenance problems to technical staff, but were grounded or docked pay when they confronted managers. Filings on aviation incidents are confidential and several officials said they were unaware of any company ever having been held criminally liable in a fatal Indonesia transportation accident.
At least 20 pilots leave Adam Air within months of joining, citing concerns that poor maintenance, corruption and rule-bending could lead to a crash.
The rapid expansion of Indonesia's budget airlines has raised concerns that growth has outpaced the supply of trained aviation professionals, regulatory oversight, parts and ground infrastructure.
The plane made a hard landing in stormy weather causing it to buckle in the middle. The aircraft was severely bent, its tail resting on the runway.