HELENA — Federal transportation safety officials are using the deadly crash of an overloaded plane in Montana to revive a long-standing debate about whether small children should be allowed to travel on the laps of adults.

The 10-seater plane crashed as it was landing in Butte in March 2009, killing all 14 people aboard, including seven children. Investigators say that several of the children were found far from the plane, suggesting that they weren’t properly restrained.

The National Transportation Safety Board is asking aviation regulators to require all passengers to have their own seats and seat belts, including children under the age of 2 who are now allowed to sit on an adult’s lap during takeoff, landing and turbulence.

The recommendation last month is similar to others the NTSB has submitted to the Federal Aviation Administration over the past two decades, only to be rebuffed. This time, the NTSB, which does not have rule-making authority, is using the Butte crash as an example.

“We strongly believe one seat, one person,” said Nora Marshall, chief of NTSB survival factors in aviation safety.

FAA spokeswoman Alison Duquette said the agency will take a fresh look at the NTSB’s recent recommendation, but the agency has no immediate plans to change its rules.

The Pilatus PC-12 was carrying three California families to a weeklong ski holiday in Bozeman, but then diverted to Butte for reasons that are still not clear and crashed into a cemetery next to the city’s airport. The seven children aboard were ages 1 through 9.

The NTSB has not completed its investigation into the cause of the crash. But the NTSB has released some new information with its latest recommendation, saying that four of the children were thrown far from the plane.

The crash was so severe that it’s unlikely anybody would have survived even with proper restraints, but the “accident renews the NTSB’s longstanding concerns” about the restraints, the recommendation reads.

The FAA agrees that the safest place for an infant or a toddler on a flight is in an approved child restraint and not an adult’s lap.

But the FAA won’t make it a requirement because the agency believes many families with small children wouldn’t pay the cost of an extra ticket, and instead would travel by highway, which statistically is much more dangerous than air travel.

The agency estimated then that a child-restraint requirement could result in 13 to 42 additional highway fatalities over 10 years.