US low-cost carrier Southwest Airlines expects to have to remove its grounded Boeing B737 Max aircraft from its flying schedule beyond the current October 1 re-entry date, Reuters reports.

The decision, communicated to the airline’s employees in an internal update from chief executive Gary Kelly, comes after the Federal Aviation Administration said it had “found a potential risk which Boeing must mitigate”.

Last week, Boeing said that it would take until at least September to solve 737 Max software issues – later than airlines had been expecting – after US aviation regulators uncovered a new problem during simulator sessions, the newswire adds.

“I’m sure this will cause us to have to take the Max out of the schedule beyond Oct. 1,” Kelly said in an internal update, adding that the company would also see “what other modifications we might need to make our plans for this year because it’s obviously extending well beyond what I had hoped.”

Kelly did not elaborate on the possible modifications. So far, the Texas-based airline has tried to substitute its Max routes with spare aircraft but has still been forced to cancel about 115 daily flights, Reuters said.

Last month, in a much needed show of support for the grounded Max, International Airlines Group (IAG) signed a letter of intent for a mix of Max 8s and Max 10s.

In separate news, Southwest Airlines was recently declared the leader in actually getting travellers from point A to point B in the shortest amount of time.