United Airlines plans to introduce optimized maintenance plans for the Boeing 737NG to smooth turnaround times for this fleet. As the aircraft get older, the carrier is finding more nonroutine work, such as corrosion and cracks, which can throw off the maintenance schedule.

The airline is working with Boeing to pull out some of the remain overnight (RON) A check maintenance tasks and create a B check, which will be done every 18 months, says John Wertz, director of technical operations.

The RON A checks each take 160-180 maintenance man-hours, depending on the cards, and Wertz says the new phased A checks will drop that to about 80 hr. The new B check should take 3-4 days, depending on the workscope.

United’s Orlando, Florida, maintenance base, which performs the 737NG’s heavy checks, will start the first bridging check around May 15, says Wertz. This check will zero out all of the A checks so that the optimized maintenance program can proceed.

The Orlando base, which completes United’s 737-700, -800 and -900 heavy checks, allocates 570 man-hours every day, 24/7, to each of its two lines at its south hangar. Its north hangar at Orlando International Airport is mostly focused on line maintenance, although it also completes tasks such as landing gear changes and out-of-service work, such as bird or lightning strikes.

By switching to the optimized maintenance checks, its Tampa, Florida, base also will be able to complete the smaller optimized A checks.

United also will be introducing optimized maintenance plans for its 777 fleet.