Bombardier has announced that CSeries flight testing will resume in September and reaffirmed that first delivery will occur in the second half of 2015.

The company’s update on 5 September narrows Bombardier’s window for lifting the three-month-old grounding of the CSeries fleet.

An oil system malfunction caused an explosion in the Pratt & Whitney PW1500G engine on FTV-1 during a ground test in Mirabel, Canada, on 29 May.

P&W proposed an initial fix to Bombardier in mid-July, but the airframer continued to pose questions to the supplier through mid-August.

"We are pleased to confirm that Pratt has now completed the first set of modified engines with full flight clearance approval from the relevant authorities including Transport Canada," says Bombardier CSeries programme manager Rob Dewar in a statement.

A photo of FTV-2 appeared online on 5 September, showing the aircraft in taxi tests with a pair of engines recently flown in from P&W’s factory in Hartford, Connecticut.

Bombardier now as a 11- to 15-month window for completing certification testing of the CSeries fleet, with roughly 300 hours of a 2,400 flight test programme completed as of 29 May.

Source: Cirium Dashboard