Aerosonic Corp. announced a first amendment to its amended and restated revolving line of credit not with BMO Harris Bank, as successor by merger to M&I Marshall & Ilsley Bank.

According to the company’s 8-K filing, it entered into the amendment that extends the maturity date from June 27, 2012 to June 27, 2013, and establishes the limit under the note at $4 million.

Aerosonic is a supplier of products for commercial, business and military aircraft.