Workers at Rolls-Royce in Barnoldswick were left in shock after bosses unveiled plans to axe 122 positions.
A 90-day consultation period got under way on Monday with union leaders and company bosses both saying they hoped to avoid any compulsory redundancies.
Workers at the aerospace giant’s two plants in Barnoldswick had been warned in January that around 30 posts could be under threat.
But Monday’s staff announcement made at the Bankfield and Ghyll Brow sites confirmed more job losses were needed before the end of the year due to a reduced workload.
An estimated 56 temporary staff may be under threat and voluntary redundancies will be sought, with the posts expected to be removed gradually throughout 2014.
Jon Brough, convener for the Unite union at Rolls-Royce, said: “It has come as a bit of a shock for the workforce because of the number of new engine orders and the numbers that need to be delivered in 2015 and 2016.
“It appears, from our point of view, that our Singapore plant will be increasing up to full capacity and unfortunately it is UK workers that will bear the brunt of these job losses.”
But company sources insisted that some of the functions carried out in Barnoldswick, which makes fan blades for a number of Trent engines and support structures for aircraft, do not take place in Singapore.
Mr Brough is now hoping to meet with Rolls-Royce chief executive John Rishton to discuss the issue before the end of the week.
A Rolls-Royce spokesman said: “We are working hard to reduce costs across our business to remain competitive.
“We must also react to changing demands from our customers and this has led to a reduced workload in our Barnoldswick facility.
“We are in the early stages of consultation with employee representatives and we hope to avoid compulsory redundancies.”
Last summer, the company was celebrating the launch of the Dreamliner and just last week announced the signing of a £660million deal with All Nippon Airways for 25 Trent 100 engines for the 787 crafts.
Coun Jennifer Purcell, who represents Barnoldswick’s Craven ward, said: “It will be a big blow for 122 families in Pendle, Burnley and the town, as its such as large part of our economy.”