Delta Air Lines could save close to $500 million in engine maintenance, Bombardier CRJ200 ownership and Delta Connection contract costs if its pilots ratify a new collective bargaining agreement they are voting on this month, the union’s contract negotiating team says.

The proposed new pilot contract includes terms that would enable Delta to drop almost 200 50-seat aircraft from its network by the end of 2015—faster than it can under the current contract—and do so shortly before many of them are due for expensive engine overhauls.

If the agreement is ratified (voting started June 15 and ends June 29) Delta will save about $184 million in “above normal run rate CRJ200 engine maintenance costs,” negotiators for the Delta Master Executive Council of the Air Line Pilots Association said in a note to members.

Delta also will save about $289 million in Delta Connection contract and CRJ200 ownership costs, they added. That provides for a total net savings of $473 million over the life of the new collective bargaining agreement, which would become amendable at the end of 2015.

A union spokesman says the savings calculations “were aggregated from costing discussions between our negotiating committee and Delta management and published to our pilots with Delta’s permission.”

The negotiators’ argument in favor of the contract is that—on an ongoing basis—Delta will be spending more than it saves on items that matter to pilots, such as higher pay and growth in the mainline fleet by the subleasing of 88 Boeing 717 aircraft from Southwest Airlines.

Delta did not have any comment.