In the middle of the night over the frozen fields of Wisconsin, Mark Blevins wrestled with the demons of ice, his single-engine Cessna struggling to stay aloft in the misty, sub-zero air.

"I tell you what," he radioed to air traffic controllers, "I got my hands full right now."

Controllers told the 41-year-old pilot he could turn back to Minneapolis - another pilot had warned that rough conditions lay ahead. But, ferrying a special delivery of auto parts to a Detroit-area factory, the northeastern Ohio pilot pressed on.

Within minutes, the plane would fall from the sky into a steep, wooded valley near the Mississippi River.

It was a typical air cargo run: late at night, in poor weather, fetching supplies for a waiting factory. And, unfortunately, it had a result more common in cargo than passenger aviation: The March, 2002, death of Mr. Blevins would help add to the gap in accident rates between the pilots who fly people versus the pilots who fly goods.

A Dutch study of global air cargo operations showed that the crash rate for air cargo carriers is five times higher than the rate for passenger carriers in North America, and even worse in other parts of the world.

It’s a reality that has seen seven die in two accidents in the last 11 years around Toledo Express Airport, the nation’s 29th largest cargo hub. Three died last month, when a Grand Aire Express plane plunged into woods less than two miles short of a runway.

The cargo vs. passenger gap has fueled a debate about what’s an acceptable number of accidents for cargo carriers such as Grand Aire, which had another crash that same day in St. Louis. The carrier has insisted it’s as safe as its five industry peers, but safety records show Grand Aire has more crashes than all five combined.

"There is absolutely zero reason why air cargo should be any less safe than commercial passenger aviation," said James Hall, former chairman of the National Transportation Safety Board and a critic of air cargo’s safety record.

Despite the questions, federal regulators have no minimum accident rates for air cargo carriers. In fact, they don’t even calculate crash rates for the companies - or the industry.

But after watching the number of accidents mount - and surprised by the reasons behind some - the NTSB has convened a hearing this fall to study the air cargo industry.

"We’re concerned about the trend - both the accident rate and the incidents that we see going on," said John Goglia, an NTSB board member. "I don’t think we’ve ever had a good look at cargo operators: how they operate, how they are [overseen] by the FAA, how they behave within the airspace."

The air cargo industry has mushroomed since Federal Express set the standard in the 1970s. Since then, hundreds of companies have made air cargo the fastest-growing segment of aviation. "And they are not all created equal, it would appear," Mr. Goglia said.

Experts say there is no single cause for the difference between the safety records of air cargo and those of passenger-hauling companies. But there does appear to be a number of contributing factors, including the fact that the industry often employs younger pilots, flies older airplanes, and more frequently flies at night and in poor weather.

Industry supporters say they’re as safe as possible.

"These operations, as a rule and over time, have been conducted quite safely and quite timely in what many would consider severe conditions," said Joseph "Jeb" Burnside, of the trade group National Air Transportation Association.

But critics argue that the disparity between the safety records of cargo and passenger carriers is tolerated for one simple reason: People complain; freight does not.

"You know what it comes down to? Body counts," said Audrey Ulozas, the mother of an air cargo pilot who died in 1997. "We don’t have enough bodies to make big news."

Air cargo pilots call themselves "freight dogs," a self-deprecating nickname noting their position in the aviation world. While commercial airline pilots fly the most modern aircraft to the most attractive destinations for the best pay, air cargo pilots are typically paid far less to haul auto parts and computer chips.

For many ambitious pilots, air cargo is a rite of passage. It’s where young pilots like Steven Petrosky learn the trade in hopes of moving up to commercial airlines. Since he first flew to Florida as a child, he knew he wanted to fly.

Fly free, he wrote in his high school yearbook. It was followed by a dark coda: Crash and burn.
"Was it an omen? Who knows," said Mrs. Ulozas, his mother.

On Aug. 7, 1997, Steven, just 26, was first officer on Fine Air Flight 101 bound for the Dominican Republic from Miami International Airport. After completing the trip, Steven expected to become a captain of the DC-8.

It was a promotion he would never see.

Federal regulators believe that as the four-engine plane’s nose crept off the runway trying to gain altitude, its cargo was dangerously out of balance: too much weight was near the tail.

So Steven, who was flying, found himself fighting a plane that didn’t want to cooperate. Just seconds after liftoff, with cockpit warnings blaring around him, he called out: "What’s going on?"

A half-minute and 3,000 feet later, Flight 101 plowed into the ground across a six-lane road and burst into flames. All four men on board, including a security guard hitching a ride, were killed, as was a motorist on the ground.

The NTSB, charged to investigate aviation crashes, was clear in its findings: Fine Air failed to monitor the loading process, and the company that loaded the plane, Aeromar, loaded it improperly.

But the NTSB laid blame elsewhere too: on the Federal Aviation Administration. The FAA, the board ruled, contributed to the accident by failing "to adequately monitor" Fine Air’s responsibilities for loading cargo.

Mrs. Ulozas believes the NTSB came to the same conclusion she has: The Fine Air crash was preventable. Since the crash, she has spent more than five years trying to make sure that what happened to her son doesn’t happen again.

"The rest of the world has to know this," she said.

Tom Rachford knew. A pilot at the time for Emery Worldwide Airlines, he had first-hand knowledge of the ails that plagued his airline. He wrote a letter to the FAA decrying the company’s maintenance efforts.

"I can’t say it any clearer: This airline is going to put a hole in the ground and kill someone. Please don’t let this fall upon deaf ears," he wrote. The pilots’ union complained again to the FAA about a year later. "Emery crews are living on borrowed time," they wrote.

Mr. Rachford, who now flies for Aloha Airlines in Hawaii, knows that the Emery crash would have triggered far more publicity if more people had been involved. And he said that would have happened if the plane had taken off on time: Less than two hours before a delayed take-off, the auto auction yard had hundreds of customers milling about.

Afterward, Mr. Rachford added his voice to Mrs. Ulozas’ and together they have been heard at the highest levels of the federal government.

Mr. Hall initially called for the air cargo study during the Emery investigation, before he left the board two years ago.

"We had the tragic loss in both the Fine Air and Emery Air of young people in accidents that should not have occurred," Mr. Hall said.

Mr. Goglia sat in the NTSB’s Washington headquarters the afternoon of April 8, when the call came: An Ohio air cargo company had had a plane crash near Toledo, killing three pilots.

Hours later a second call came - the same company had another plane crash in the Mississippi River in St. Louis, injuring two pilots.

"I was on the phone immediately," he recalled. "The whole thing was, ‘What’s going on with that operation?’ ... Good planes don’t just crash. Something is happening here."

Except for the 2001 terrorist attacks, it was the first known time any U.S. carrier had lost two planes on the same day. The crashes became Grand Aire’s ninth and 10th in the last 10 years. A Blade story in April identified nine of the crashes, but omitted one because of incomplete federal record-keeping.

The firm’s owner, Tahir Cheema, voluntarily grounded the fleet for a week, saying he wanted to figure out what had gone wrong. But he was adamant that his company was just as safe as its competitors.

"Look at their record[s] and then compare," he said.

Of the five competitors named by Mr. Cheema, a review by The Blade has found that one had four crashes involving on-demand air cargo, and the rest had two or less.

Among them was the Belleville, Mich.-based Active Aero. The firm had a fatal crash in 1993 and was purchased a year later. Since then, the carrier’s only mention with the safety board was the time a flock of geese flew into engines during a landing.

"We believe that 10 incidents or accidents [involving Grand Aire] in the last 10 years is significantly higher than the industry standard," said Active Aero’s attorney, Don McNeff.

Grand Aire declined to comment, referring industry questions to the National Air Transportation Association, which represents on-demand cargo companies.

The association’s Mr. Burnside said it’s too soon to pass judgment on Grand Aire.

"I think Grand Air has had a spate of bad luck. There might be some systemic issues there. We don’t know," he said. "In fact, neither the NTSB or the FAA knows at this point."

And it’s difficult to calculate a comparable crash rate for Grand Aire or its competitors. For smaller carriers, regulators don’t collect the number of departures, miles flown, or hours flown by each carrier - key pieces of data needed to compute accident rates.

It’s part of a broader problem Mr. Goglia acknowledged exists in the regulation of air cargo: The hard data haven’t been collected and crunched to really determine who’s safe.

"There’s no good measurement," Mr. Goglia said.

Without comparable crash-rate data, what’s left is a collection of anecdotes, such as the crash of Mr. Blevins.

On a cold spring night last year, Dallas-based Ameristar got a call to ship four boxes of auto parts from Minneapolis to Detroit. It subcontracted the flight to a smaller charter operator, Royal Air.

It was only 100 pounds of freight, but it wouldn’t be an easy flight. A late winter storm was blowing snow in the Upper Midwest, creating enough mist to collect on wings and form ice so heavy a plane could struggle to keep aloft, according to a preliminary NTSB report on the crash.

Because of the ice, Royal Air’s pilot had to make an emergency landing at another airport about 100 miles short of Minneapolis. So Ameristar called Priority Air Charter, a small carrier based near Massillon. It took the job.

Mr. Blevins landed at Minneapolis about midnight with a plane already coated in ice up to three-fourths of an inch thick, and he told airport workers that it was "pretty bad up there." But he declined their offer to spray de-icing chemicals on his plane, instead chipping off some ice himself before taking off shortly after 1 a.m..

He immediately ran into problems. More ice coated his wings as he struggled to find the right altitude to avoid the freezing mist. About 20 minutes into the flight, he told an air traffic controller that he needed to find somewhere to land, and they settled on an airport 20 miles away.

He didn’t make it.

Cargo pilots are the flying truck drivers behind a transportation revolution.

With the increasing demand for just-in-time delivery, air cargo became the safety net for manufacturers trying to trim costs.

Rather than stockpiling supplies in huge buildings, manufacturers have turned to rolling - and, increasingly, flying - warehouses.

If a temporary gap exists in a supply line, a company can quickly dispatch a couple hundred pounds of widgets by plane to keep production lines moving. The flight may cost thousands of dollars, but it’s cheaper than shutting down an assembly line.

The air cargo industry boomed in the 1990s but has taken a downturn with the latest recession. Still, a pyramid of firms remain, shipping everything from auto parts to mail across the world.

Priority Air and Grand Aire are among the many small and mid-size companies that handle on-demand air cargo - generally considered the entry-level of cargo flying. Pilots often fly older planes in the middle of the night - usually on short notice - to smaller airports under tougher conditions.

Up the food chain are the bigger cargo carriers with scheduled service, including BAX Global. The company’s hub at Toledo Express is responsible for much of the cargo that passes through Toledo, and 11 years ago one of its DC-8 planes crashed two miles north of the airport - killing three crewman and a pilot along for the ride.

Regulations vary within the cargo industry, just as within passenger service. The FAA imposes looser rules as the planes get smaller and flights become on-demand - whether they’re carrying people or cargo. And there are no government studies looking at each industry’s safety record.

But the Dutch study, looking at 30 years of accident records, found a pronounced gap in safety between passenger and cargo carriers.

Looking at larger planes, the study showed that air cargo safety trailed passenger safety in almost every part of the world. In North America, the accident rate for air cargo was 2.5 accidents for every million flights, compared to 0.5 accidents per million flights for passenger service.

Despite the gap, the study pointed to no single cause. Instead, it said it derives from a number of issues, many related to economics. They found that air cargo operators:

Fly more often at night. Studies, including one by NASA, have shown the human body performs worse at night.

Fly older aircraft. The average age of the air cargo fleet in North America is twice as old as the passenger fleet. Older planes have fewer modern safety features, including mid-air collision warning devices. Sometimes, the study said, safety equipment is removed when passenger planes are converted to cargo use.

Have less experienced pilots. Because the conditions are less attractive, air cargo often hires pilots trying to gain experience. Many are willing to pay the air cargo carrier for their training.

The study, presented in 2000, helps fuel the arguments of people like Mr. Rachford, who said air cargo maintenance requirements are barely met and corners often cut.

Others, like Active Aero’s Mr. McNeff, said the real problems are not with the entire cargo industry, just renegade carriers.

"Just because you’re flying cargo, you’re not less safe," he said. "It really comes down to the individual carriers and their definitions of safety."

But Mr. Hall, who watched over aviation safety for much of the last decade, disagrees. He believes air cargo lags behind passenger carriers in attitude and action.

"I think we were able to build a strong safety culture that is paying dividends today in the type of safety record we’re seeing in commercial [passenger] aviation," he said.

"We have never had that same emphasis on air cargo."

Steven and Judy Forshay have a lot of questions about what went wrong when their son Will’s Grand Aire plane crashed while trying to land at Toledo Express last month, and they know they probably won’t get answers for months, if not years.

But they already have an idea on how to improve safety: require voice cockpit recorders in all planes. Regulators don’t require them in planes as small as Grand Aire’s.

"If Will were able to speak in the last 15 seconds, that this is malfunctioning, [that recorded conversation] could help prevent other accidents, and other deaths," Mr. Forshay said.

It’s among the many ideas from safety advocates and families of dead crewman across the country. Some want all cargo planes equipped to record flight data, which could quickly be reviewed after a crash, as well as equipment that warns of potential mid-air collisions.

But the industry is reluctant.

Mr. Burnside said some cargo carriers may not need the collision-avoidance equipment because they fly at night: There’s less traffic, and it’s easier to see lights from nearby planes.

And equipping small planes with voice recorders, data recorders, and the required sensors would mean taking apart the entire aircraft and probably cost as much as the value of some planes, he said.

"I know it sounds crass, but at the end of the day, you look at a cost-benefit analysis of keeping or installing this equipment, and it’s a no-brainer," he said.

Beyond requiring more equipment, advocates want the FAA to hire more inspectors. After Grand Aire’s crashes, the agency added six part-time inspectors to monitor the company. The company already had three FAA inspectors working solely on Grand Aire.

Mr. Rachford hopes the NTSB’s hearings will help the five-member safety board push for change.

"If they actually follow through with it and give it the proper oversight," he said, "then all the work over the years - it’ll be worth it."