Major US carrier Southwest Airlines faces a deadline on Tuesday to reach an agreement with the Federal Aviation Administration (FAA) over the replacement of parts on 82 Boeing 737 aircraft, and failure could result in jets being grounded.

Talks between both the airline and the FAA continued yesterday as the sides try to set up a schedule to replace the hinges on the back of wings for the jets.  Southwest grounded 46 planes late last before the FAA granted a 10-day waiver.

The parts in question were installed by a third-party maintenance contractor that didn’t have proper permission to install the parts.

The parts, installed by a third-party maintenance contractor and not by Southwest’s own aircraft mechanics, didn’t have proper permission to install the parts in question.

Southwest has since suspended the vendor, D-Velco, which was subcontracted to rplace the parts.

The replacement of parts undertaken by an approved vendor could take up to three months.

“We are still in talks with the FAA to allow us to continue replacing these good parts in a timely manner for minimal disruption to air service for customers,” Southwest spokeswoman Beth Harbin said Monday.

The FAA said Friday that talks were still ongoing.