Workers at the Rockwell Collins plant in Manchester celebrated its 25th anniversary this week. Plant manager Michael Sebeny says things started in 1977 in an old building in downtown Manchester, but the new facility’s been up for 13 years. Sebeny says the company’s been able to maintain a fairly steady workforce even in uncertain times.There are close to 200 workers, though they’ve had to make cuts lately with downturns in the economy and airline travel. Sebeny says he hopes the Manchester Rockwell Collins plant will soon be back up to full employment.