Southwest Airlines Co. is increasing its inspections of jet engine fan blades like one that cracked and broke loose in April, killing a passenger, after fissures were found in blades on other planes.

The carrier made the change after General Electric Co., part of a venture that makes the engines, found a cracked blade during post-accident inspections in another Southwest engine, and spotted four or five more in other airlines’ planes, Southwest Chief Operating Officer Mike Van de Ven said Thursday.

Southwest is inspecting the blades at every 1,600 flights instead of the 3,000 required by the Federal Aviation Administration, Southwest Chief Executive Officer Gary Kelly said in an interview with Bloomberg News. The change, implemented in June, applies to engines that have already performed 30,000 flights.

The engine manufacturer is considering recommending inspections every 1,600 to 1,800 flights instead of the current 3,000, Van de Ven said on a conference call to discuss earnings.

After the April 17 incident, in which a cracked blade broke and sent debris into a window on a Southwest flight, the engine manufacturer and aviation regulators issued urgent new requirements for inspections to find similar flaws. The FAA required the 3,000 flight inspections as a result of the accident.

The engine is made by CFM International Inc., a joint venture between General Electric Co. and France’s Safran SA. Spokesmen for GE and the FAA didn’t respond to requests for comment.

GE determined that more frequent lubrication of the blades potentially could help avoid damage, Van de Ven said.

“GE is working through the protocols they think will be necessary going forward,” Kelly said.

The National Transportation Safety Board said Tuesday that it will hold an investigative hearing on the engine’s failure, a signal that the agency is giving the incident a high priority.

The Nov. 14 session will focus on the fan blades’ design and development, how that engine model is inspected and the way debris is supposed to be contained in a failure, the NTSB said in a statement.

Jet engines are encased in a hardened shell so that if fan blades or other components break loose, they won’t fly out and hit such critical areas as fuel tanks or the passenger compartments.

In the April 17 failure, the fan blade bounced in front of the protective sheath, the NTSB has said. It then broke apart the unprotected engine inlet, a wing-like structure that smooths the air flow into the turbine.

Parts of the inlet showered the plane with debris. One window was struck so hard that it broke, prompting a violent decompression of the cabin and partially sucking a woman passenger out of the plane. It was the first passenger death on a U.S. carrier in more than nine years.