By James Pilcher
The Cincinnati Enquirer

The Federal Aviation Administration has ordered all domestic airlines that use a popular model of regional jet to inspect the planes for possible cracking.

If left unchecked, the cracking could cause rapid depressurization of the cabin while in flight.

The "airworthiness directive" goes into effect today and requires airlines such as Erlanger-based Comair to increase inspections of a certain part of the fuselage of the Bombardier-made Canadair Regional Jet Series 100 and its 44-seat variant.

If a cabin loses pressure at its normal altitude, it could cause passengers and even crew to eventually lose consciousness if they are not wearing oxygen masks.

Such an occurrence wouldn't necessarily mean any mechanical malfunctions, however. And decompression has not happened in any of the affected planes.

"We've not experienced that at all," Burt Cruickshank, a spokesman with Montreal-based Bombardier Aerospace's regional jet division, said Tuesday.

Comair spokesman Nick Miller said the airline had conducted the required inspections on all the affected planes.

"I know for a fact that we have not detected any of the cracking that is mentioned in the airworthiness directive," Miller said.

It was unclear from the directive, which was issued May 1, how often the inspections were required previously, but they must now be done every 10,000 "cycles"; a cycle is one takeoff and one landing.

Comair has 97 CRJ-100s in its 138-plane fleet. Bombardier began making the plane in 1991 and replaced it with the 200 series in 1996; there were 226 CRJ-100s delivered worldwide and another 21 of the 44-seat variety.

Cruickshank said 271 planes had been inspected worldwide and that "minor cracks" were found in 12.

"This is a robust plane ... but cracking is not uncommon in older models," Cruickshank said.

The FAA order mirrors one issued in October 2002 by the FAA's counterpart in Canada, Transit Canada Civil Aviation, which oversees aviation in that country.

That directive was issued after cracks were found last year in some CRJ-100s owned by German airline Lufthansa, Cruickshank said.

Any planes that have cracks can be temporarily repaired until the next scheduled major overhaul, when they are permanently repaired, Cruickshank said.

The order "is to make sure the maintenance is done as required," he said. "This is a maintenance issue, not a safety issue."

E-mail jpilcher@enquirer.com