MONTREAL -- Bombardier Aerospace says its CSeries commercial jetliner will resume test flights later this month following an "engine incident" that grounded the aircraft in May.

The precise timing of the first flight was not disclosed.

The company said Friday that it has worked with engine maker Pratt & Whitney to come up with a fix that has been incorporated into the engine's oil lubrication system.

Rob Dewar, vice-president of the CSeries program, says the company is confident the CS100 aircraft will enter into service in the second half of next year despite the four-month delay in flight testing.

In June, Bombardier chairman Laurent Beaudoin suggested the flight tests would only be put on hold for a month following the malfunction which occurred during maintenance testing on the ground.

The aircraft has completed 300 of 2,400 hours of flight tests required to win certification.

The company has not disclosed the cause of the May 29 incident that damaged a test aircraft and grounded flight testing, but it said the CSeries program has made headway in recent months by completing a series of activities including additional ground tests and software upgrades.

The impending resumption of flight tests comes after the Montreal-based company created a team dedicated to the development of its business and commercial aircraft programs.

The change follows the departure of key aircraft development program leaders as part of a reorganization that will shed some 1,800 non-union employees.

Francois Caza, a veteran employee with nearly 30 years experience, has been appointed vice-president product development and chief engineer.

The position has been carved from the newly created aerostructures division that was announced in July with the retirement of aerospace president Guy Hachey. Caza will report directly to Bombardier CEO Pierre Beaudoin, alongside the heads of business aircraft, commercial aircraft and transportation.

Spokeswoman Isabelle Gauthier says the reorganization set to be completed this year is designed to ensure the company meets the entry into service of its new programs -- CSeries, Learjet 85 and Global 7000/8000.

Meanwhile, Bombardier will inform employees in the coming weeks if they will be forced to leave the company. More than half of the 1,800 employees who will depart will be located in the Montreal area and Toronto.