Montana Aviation Beacons

In 1965 the FAA surveyed the Montana beacon system and grouped them, identifying "Group I", those that should be decommissioned and "Group II" as those to remain lit.

Many airway beacons included large concrete arrows intended to direct pilots in the direction toward the next beacon in the airway, like this one near Grants, New Mexico

Mullen Beacon on Lookout Pass in summer

Generator house foundation, electrical shed and southwest corner of the MacDonald Pass Airway Beacon

A patent application schematic for a directional airway beacon light, submitted by J.B. Bartow in 1931

View to the top of the MacDonald Pass Airway Beacon

The MacDonald Pass Beacon west of Helena. This was the last beacon completed for a lighted airway connecting Minneapolis with Seattle. A crowd of 4,000 celebrated its completion in 1934.

View of the MacDonald Pass Beacon west of Helena - now on the National Register of Historic Places

The Wolf Creek Beacon southwest of Great Falls. The shack was used as a warming shelter in case of bad weather or during a winter service trip. They were stocked with provisions to spend the night if needed

Wilhelm points out Hardy Creek Beacon on an aviation map.

Wilhelm's personal record is 27 minutes to the top of the hill the beacon is built on.

The terrain leading up to the beacon is steep, rocky and lacking a distinct trail.

Ken Wilhelm climbs toward the Hardy Creek aviation beacon, a visual navigation tool from before radio or GPS, to perform routine maintenance Friday, Oct. 2, 2015. Montana is the only state that still maintains 17 operational beacons in mountainous areas.

Ken Wilhelm holds up a mercury vapor lightbulb that will, if necessary, replace the one currently in use.

A view of the Missouri River from the hike towards the beacon.

Maintenance logs from 1994 and older are etched in pencil in the utility box at the base of the tower. Wilhelm and those who came before him turn on the circuits and count how many seconds it takes for the beacon to light as a way of checking electrical flow.

An old maintenance log hangs in the utility box at the base of the beacon tower.

Ken Wilhelm adjusts his harness before climbing down the 90 foot tower. Most of the 17 towers are 50 feet tall, though some are 12 feet tall.

Wilhelm shows a lightbulb that will go in one of the 15 degree beacons.

Ken Wilhelm changes a lightbulb in one of the two 15 degree visual lights. The each tower's 15 degree lights blink a different morse code letter to let pilots know where they are on the route. The Hardy Creek Beacon's letter is R.

A series of switches in a utility box on top of the beacon provide power to the motor and other functions.

Wilhelm sprays oil onto the engine to ensure it continues to run smoothly.

Ken Wilhelm cleans the engine of the main beacon.

Ken Wilhelm changes the mercury vapor lightbulb in the main beacon.

Ken Wilhelm explains his maintenance procedure at the top of the beacon. There are two lights on opposite sides of the tower that cannot be seen if the pilot strays more than 15 degrees off course, though the main rotating light remains visible. Wilhelm is responsible for checking the bulbs on all 3 lamps and the engine of the main beacon.

A cable system was installed on the tower ladders for safety within the past decade.