The skies over Glacier National Park will be noisier this summer, and helicopters lugging seat-belted tourists don’t deserve all the blame. Park managers are increasing their own helicopter and airplane traffic to do backcountry chores, adding 52 flights to their recent average of 50 per summer.

According to an environmental assessment, the park’s air force will use almost two-thirds of the planned flights to haul sewage from Granite Park Chalet and elsewhere in the backcountry, and to carry crews and supplies to restore the historic Porcupine Lookout.

Ironically, at the same time that it is ramping up its own flights, the park wants the Federal Aviation Administration to ban commercial flights for tourists, which have increased to about 1,500 flights per year.

The air tours disturb wildlife and quiet, says Mary Riddle, an environmental protection specialist for Glacier, while work flights tend to be briefer and comply with “a stringent review process.”