Boeing Co. will start sending out layoff notices tomorrow to as many as 700 engineers as it seeks to cut as many as 1,700 engineering jobs by the end of the year.

The cuts are necessary because development work is winding down on programs such as the 747-8 and the 787-9 while work hasn’t yet been approved by Boeing’s board for the 777-X and 787-10, Mike Delaney, vice president of engineering for Boeing Commercial Airplanes, said in an e-mail to managers.

Some of the cuts will be mitigated through attrition and a reduction in contract labor, Delaney wrote.