An Indonesian jetliner battled sudden wind shear before crash-landing, damaging an emergency door in business class that may have prevented some passengers from escaping after it erupted in flames, the pilot and an investigator said Friday.

Twenty-one people died, but 119 others survived after scrambling through exits at the back of the Boeing 737-400's cabin through black smoke and flames.

The Garuda Airlines crash — the fourth involving a commercial jetliner since 2005 — has put the spotlight back on Indonesia's aviation safety record. Experts say poor maintenance, rule-bending and a shortage of trained professionals in the country's booming aviation industry are likely factors in the disasters.

Vice President Yusuf Kalla said Friday that Indonesia should be "ashamed," and vowed to replace several top Transport Ministry officials. "We will issue stronger regulations and older aircraft will be banned."

Investigators say data from the plane's flight recorders, which are being analyzed in Australia, was needed before drawing any firm conclusions on the cause of Wednesday's crash at Yogyakarta's international airport.

But the pilot of doomed aircraft said "he felt a very powerful downdraft just before landing," Capt. Stephanus Geraldus, president of Garuda's pilots' association, told The Associated Press, referring to a phenomena typically caused by differences in air temperature or pressure.

Such wind shears have been blamed in other accidents involving commercial jetliners.

Pilots experiencing a strong downdraft are "one moment sitting with the aircraft under control and the next minute pushed to the ground very rapidly," said Tom Ballantyne, chief correspondent of Orient Aviation magazine.

"As he reacts, the aircraft will become slightly unstable, it may start to shudder or shake," Ballantyne said, adding that while there are standard ways to restore control of the plane, the pilot's natural reaction is unfortunately to speed up.

"When the wind changes direction again, he ends up going too fast," he said.

Several passengers reported that plane appeared to be traveling too fast as it approached the runway for landing.

Investigators said front wheels of the plane snapped off on landing and that fuel from a punctured tank in the right wing fed the flames, which reached up to 1,112 degrees Fahrenheit.

Many of the dead were sitting in business class.

"We found that the front left door could not be opened because it was damaged when the plane hit a dike," said crash investigator Frans Wenas. "It is possible that some of the passengers could not get out because of that."

Australian Federal Police Commissioner Mick Keelty said Friday it was too early in the investigation to speculate on the cause of the crash, though he had also been told of reports of wind shear.

"We really won't know until all the data is known and all the exhibits put back together," he told Australian Broadcasting Corp.