By contrast, he said, Part 135 carriers are overseen by an inspector juggling a half-dozen or more carriers.

"The 121 guys, the principal is almost joined at the hip with them," said Crotty, now a civil aviation consultant. "For 135 guys, they may be there, they may not. It's the old 'out of sight, out of mind.' ''

In a statement, the FAA said most 135 carriers "are not comparable in scope to Part 121 air carriers, sometimes consisting of only one or two aircraft and a like number of pilots. It would be impractical to devote a single inspector's workload to a single Part 135 carrier in many instances because the operator is simply too small to justify that workload."

In 2004, safety advocates eyed an avenue for change: an Air Cargo Safety Forum in Virginia.

"The regulatory differences between cargo and passenger operators contribute to increased risk in the cargo industry, and likely to the higher cargo airline accident rates," wrote the Air Line Pilots Association, which represents larger cargo operators.

The group's proposal to set a standard level of safety never made it through the first step -- a study process -- even though federal aviation officials were at the table.

"There was obviously a reluctance on the part of the cargo carriers to do anything, for obvious reasons. They saw it was going to cost them money," said captain Terry McVenes, executive air safety chairman for the pilots group. ''Their feeling was there was nothing wrong with it anyway, so why would we do anything? But I would say the statistics show there were some issues."

He adds: "We always want to be sensitive to cost. But cost at what price?"

The Cargo Airline Association, a Washington group including FedEx Express, UPS and DHL Express, did not respond to five Miami Herald interview requests since November.

"Those planning sessions were less than friendly," McVenes said. "They just did not want to be there at the table."