NEW YORK (Reuters) – New engines made by Pratt & Whitney for the latest Airbus single-aisle jetliner, the A320neo, pose a potential shutdown risk, the U.S. aviation regulator said on Wednesday.

The Federal Aviation Administration’s formal warning follows a similar action by European regulators on Feb. 9, and cites a “knife edge seal fracture” in the engine that could lead to an engine stall “and consequent inflight shutdown and rejected takeoffs,” the FAA said in an airworthiness directive.

The warnings mark the latest in a string of issues that have clouded the rollout of Pratt’s new engines, which compete with market-leader CFM International, a joint venture of General Electric Co and Safran SA of France.

A total of 98 engines could be affected, with 43 confirmed to have the problem and the rest possibly affected, Pratt said. The company declined to comment further.

Pratt has not halted production or delivery of the engines, and the Connecticut-based company plans to submit a proposal to European regulators on Friday detailing how to fix the problem, according to a person familiar with the situation.

It wasn’t clear how quickly the European Aviation Safety Agency could approve the plan.

The problem affects only PW-1100 series engines, not similar Pratt engines for Bombardier, Embraer or Mitsubishi jets, the source said.

Airbus halted delivery of A320neos after delivering 113 of them. It was not immediately clear which airlines had the largest fleet. Industry sources said 20 Airbus A320neos had been grounded by airlines because of the problem.

Reuters