9. PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS

The following table is a consolidated disclosure of all domestic and foreign defined benefit pension plans as described in the Corporation’s 2017 Annual Report on Form 10-K filed with the SEC.

Pension Plans

The components of net periodic pension cost for the three months ended March 31, 2018 and 2017 are as follows:



	Three Months Ended
	March 31,
(In thousands)	2018			2017
Service cost	$	6,506		$	6,471
Interest cost	6,534			6,219
Expected return on plan assets	(14,716		)	(13,285		)
Amortization of prior service cost	(63		)	(25		)
Amortization of unrecognized actuarial loss	3,906			3,581
Net periodic benefit cost	$	2,167		$	2,961

During the three months ended March 31, 2018, the Corporation made a $50 million contribution to the Curtiss-Wright Pension Plan. The Corporation does not expect to make any further contributions in 2018. Contributions to the foreign benefit plans are not expected to be material in 2018.

Defined Contribution Retirement Plan

Effective January 1, 2014, all non-union employees who were not currently receiving final or career average pay benefits became eligible to receive employer contributions in the Corporation's sponsored 401(k) plan. The employer contributions include both employer match and non-elective contribution components, up to a maximum employer contribution of 6% of eligible compensation. During the three months ended March 31, 2018 and 2017, the expense relating to the plan was $4.2 million and $3.7 million, respectively. The Corporation made $9.2 million in contributions to the plan for the first quarter of 2018, and expects to make total contributions of $14.0 million in 2018.