US Airways Express’ largest regional jets by February 2012 will be retrofitted with a first-class cabin under a $35 million plan unveiled by the carrier.

The retrofit will start in October when 38 Embraer 175s operated for US Airways by Republic Airways Holdings currently offering 86 seats across a single class will be upgraded with an eight-seat, first-class cabin in a 1x2 configuration.

A further 20 Embraer 170s also operated by Republic, 38 Bombardier CRJ900s contracted from Mesa Air Group and 14 CRJ700s operated by US Airways’ wholly owned subsidiary PSA will also be retrofitted by the end of January 2012, with nine seats up front across the three types.

The changes will be revenue-positive in the first year of operation due to the higher value of the seats’ fares and upgrade sales, notes US Airways. With the new configuration, the 70-seat CRJ700s lose just three seats when retrofitted, while the CRJ900s and E-170s drop seven economy seats to accommodate the new first-class cabin.

After the retrofit, Republic’s E-175s will provide 80 seats, six fewer than the current configuration. This first class, along with that to be installed in the CRJ700s and E-170s, will offer a 37-in. pitch, while the CRJ900s will provide a further one inch between the headrests.

The remaining economy-class seats will retain their 31- in. pitch. All seats are manufactured by C&D Zodiac.

US Airways’ retrofit program does not affect the configuration of the 50-seat regional jets operated under its Express brand, matching cabin reconfiguration programs already enacted by the carrier’s domestic peers.

“With the installation of first class on US Airways’ Express partner aircraft we’re able to offer our first-class customers seamless, same-class service to the more than 85 destinations these aircraft serve,” says US Airways Senior VP-Marketing and Planning Andrew Nocella, adding, “This will also offer our Dividend Miles Preferred members complimentary upgrades on nearly 640 more flights each day.”

US Airways also notes that the retrofit provides product continuity for a greater part of its fleet, which already offers first class on domestic mainline services. Because of US Airways’ pilot labor contract, this mainline fleet already includes Embraer 190s configured with 11 seats up front and 88 in economy.

The airline also tells Aviation Week the small reduction in capacity has already been accounted for in the carrier’s guidance.