Bumpy runways, hair-raising safety lapses, remote airstrips with no navigation systems and a dire shortage of experienced captains and maintenance crews.
Indonesia is one of the world's fastest-growing aviation markets, but it has come under fresh scrutiny since a fatal Lion Air crash last month as the sector struggles to keep up with its breakneck expansion, putting safety at risk, analysts warn.
"The vast increase in demand and operations has seen more regular accidents or events taking place that are preventable," said Stephen Wright, an aviation expert at the University of Leeds.
On Wednesday, investigators issued a preliminary report that said the doomed Lion Air jet had technical problems that the airline failed to fix before its final flight.
All 189 people on board were killed as the nearly new Boeing 737 slammed into the sea shortly after takeoff.
While officials did not lay blame or pinpoint a definitive cause of the October 29 accident, they said the budget carrier must take steps "to improve (its) safety culture".
Despite a spotty safety record and an avalanche of complaints over shoddy service, the carrier's parent Lion Air Group -- which also operates five other airlines -- has captured half the domestic market in less than 20 years of operation.
The group now has Southeast Asia's biggest fleet -- more than 300 planes -- with growth driven by a model built on cheap prices and flights to almost every corner of the vast Indonesian archipelago.
- 'Worst in the world' -
Indonesia's safety record has improved, analysts say, since its airlines including national carrier Garuda were banned for years from US and European airspace for safety violations.
Still, the country has recorded 40 fatal aviation accidents over the past 15 years.
The US and EU flight bans have been lifted in recent years, but the industry is still wrestling with outdated infrastructure, accusations of cutting corners and heavy restrictions on hiring pilots and technicians from overseas to plug staff gaps.
"If you want to grow quickly, you have to hire foreigners but here we have regulations which prevent us from easily hiring them," said Jakarta-based aviation analyst Gerry Soejatman.
Lion Air -- which captured headlines in 2011 with a then-record $22-billion order for Boeing planes -- sits at the centre of a $4-billion-plus sector with double-digit annual growth and 97 million domestic travellers last year alone.
The carrier's chief, Edward Sirait, acknowledged that people may see Lion as a "tacky company" that hires "grumpy" service staff straight out of high school.
But he disputed any suggestion that pilots -- including those that fly on international routes -- are not properly trained.
"They'd never be able to fly abroad if they weren't qualified," he told AFP.
Indonesia's transport ministry said it is pushing Lion and other airlines for safety and service improvements.
Some Indonesian lawmakers, however, want the budget carrier's licence to be revoked, a call that may be bolstered by Wednesday's report.
Such punishment is unlikely given the size of the Lion Air Group, a major employer that has ballooned as Indonesia's growing economy and rising incomes have given more of its 260 million people access to air travel.
Its co-founder Rusdi Kirana -- who described his own airline as the "worst in the world" in a 2015 interview -- is a close confidante of President Joko Widodo, who appointed him to the key post of Indonesia's ambassador to neighbouring Malaysia.
And the firm's growth strategy is crucial to Widodo's infrastructure push, which includes plans for dozens of new airports including a $10-billion hub in the capital, as he seeks re-election next year.
Lion Air is also the only carrier to service many remote parts of a 17,000-island country, where some of the more than 200 airports don't even have proper navigation equipment.
That means pilots have been forced to use their sight alone while landing over perilous terrain and on less-than-smooth runways.
"There are still many runways with uneven surfaces so when the plane lands its feels like you're driving on a potholed road," said Lion Air captain Yusni Maryan.
- 'No clue' -
As a frequent flyer, Indonesian civil servant Amalia Pissano has her share of horror stories, from the Lion Air captain who delayed a flight for two hours so he could have a meal to a terrifying experience aboard a Sriwijaya Air flight on the same route as the crashed Lion jet.
The plane suddenly began shaking violently before it plunged toward the ground, sparking chaos inside the cabin until pilots regained control and landed safely, she said.
The crew never offered an explanation, Pissano said.
"It was really scary because the plane was rocking and the crew seemed to have no clue what was happening."
