The storm was too big to fly around, but rather than turn back, Captain Ivan Korogodin decided to risk flying over the towering clouds.

As the Tupolev-154 jet approached its maximum operating altitude of 39,400 feet, or 12,000 meters, it stalled and went into an uncontrollable spin. It slammed into the ground, killing all 170 on board.

The August crash last year of Pulkovo Airlines Flight 612 from the Black Sea resort of Anapa to St. Petersburg was officially attributed to pilot error. Safety advocates, however, see it as symptomatic of much deeper problems in Russian aviation: a growing fleet of small, low-budget airlines; under-trained pilots; weak government regulation; and a cost-cutting mentality that sometimes causes pilots who abort flights and landings to be fined.

Russia and the other former Soviet republics had the worst air traffic safety record in the world last year, with an accident rate 13 times the world average, according to the International Air Transport Association.

Last year, planes flown by Russian carriers were responsible for the deaths of 318 people in two major crashes and eight lesser ones - close to half the world's total of 755 fatalities reported by the International Civil Aviation Organization. In Russia and the former Soviet republics together, the combined death toll was 466.

Regulators and some analysts dismissed the spike in crashes as a fluke and challenged the methodology of the count.

But other international surveys also showed Russia leading in crashes and fatalities.

Some international pressure has come to bear on Russian airlines to improve their safety standards. After consultations with the Russian authorities, the European Union in late June barred four Russian carriers - Kuban Airlines, Yakutia Airlines, Airlines 400 and Kavminvodyavia - from flying into airports in the region. Restrictions were also placed on certain aircraft flown by six others: Gazpromavia, UTAir, KrasAir, Atlant Soyuz, Ural Airlines and Rossiya, the airline that operates the Russian presidential jet.

Experts, including pilots who fly the former Soviet skies, say government bodies tolerate practices that are wrecking a once honorable safety record.

In interviews with the Associated Press, they said that regulation was lax, while airlines overworked their crews and fined pilots for using too much fuel. Many carriers, critics say, also skimp on crew training and cut corners on maintenance of their aging Soviet-built aircraft and secondhand Western planes.

The state-controlled carrier Aeroflot, the privately owned Transaero and some other big airlines have modern planes, skilled crews and world-class safety records, experts agree. But many smaller carriers, they say, cut corners on safety.

The rules said Flight 612 should have turned back to avoid the storm, yet Korogodin, who had logged more than 12,000 flight hours, pressed on, possibly because he trusted his luck, possibly because he wanted to save fuel.

Airline officials insist that fuel conservation incentives and fines do not apply to extreme conditions and do not affect safety. But Oleg Smirnov, who heads the Partner of Civil Aviation Foundation, a nonprofit body, is skeptical.

"Naturally no one would admit publicly that flight safety isn't the top priority," said Smirnov, a veteran pilot who was a deputy aviation minister in Soviet times. "But nonprofessionals now in charge of many airlines - former economists, lawyers and even dentists - think only about money."

"Some companies keep dossiers recording how much fuel a captain expends on his flights," he said. "If he expends extra, he is told: 'You get no bonus now, and if you keep acting like that we shall think whether the company needs you.' That sits deeply in pilot's brain and guides his actions."

Anatoly Knyshov, a highly decorated test pilot with 41 years' experience, said: "Business managers run for profits and neglect safety."

Some airlines allegedly penalize the crews for failing to land on the first attempt - a practice that may have led to the most recent deadly crash in Russia, in March, of a Tupolev-134 whose pilot hit the ground trying to land in fog even though he could not see the tarmac lights.

Six were killed and 20 injured.

Russia's civil aviation is overseen by five government agencies, two of which both regulate the industry and investigate accidents. Blame is invariably pinned on the crew rather than regulatory failures.

"In the end, no one is responsible for anything," said Knyshov, the test pilot, who recently wrote to President Vladimir Putin, urging action to save Russian aviation from ruin.

After the 1991 Soviet collapse, 500 "babyflots" - offshoots of the Aeroflot monopoly - sprang up. Today there are 182, and the smaller ones are more likely to sacrifice safety to cut costs, critics say.

Low pay is also a safety issue, said Miroslav Boichuk, chief of the Cockpit Personnel Association of Russia. Despite increases in recent years, average pilots' salaries of around US$2,000 a month are far lower than those in the West, and pay typically depends on how much time pilots spend flying - a practice, Boichuk said, that can exhaust them and impair their judgment.

Standards at state-run flight schools have declined steeply since the Soviet era. Rookie pilots like Andrei Khodnevich - who was co-pilot of Flight 612 and at the controls when it crashed - log about 60 flight hours during training, mostly in old propeller planes. That is less than half the minimum of 150 hours in modern planes required by Western flight schools.

Only 20 percent of training planes are airworthy and instructors earn less than a tenth of the pay of a commercial pilot in Russia.

Student pilots, meanwhile, may be distracted from their studies by hunger. The daily food subsidy at government flight schools is US$1.90. "Even a police dog gets more," said Smirnov, the former deputy minister.

Critics say Russian pilots are not being properly trained on the secondhand Boeings and Airbuses that are increasing in use.

Last year an Airbus A310 skidded off a runway in the Siberian city of Irkutsk and slammed into a row of garages, killing 125 people. The pilot had instinctively worked the controls as if he were flying a Soviet-designed plane, and accelerated instead of slowing down.

One more issue, say critics, is a legal system that avoids exposing airlines to expensive lawsuits.

"Forcing at least one carrier to pay sizable compensation would have a sobering impact on others," said Vitaly Yusko, whose 10-year old daughter, a sister and her two sons died in an airliner crash.

"That would help end their feeling of total impunity."