BETHEL — A shift has occurred in the mix of military hardware winging over the heads of Western Mainers.

But the impact on the level of noise those on the ground hear from low-flying fighter jets remains unclear.

The change involves the 104th Fighter Wing of the Massachusetts Air National Guard, which has recently completed a conversion from A-10 Warthogs to F-15 Eagles.
Those nicknames suggest the differences between the relatively slow, ground-hugging A-10 and the much faster, higher-flying F-15.

“The A-10 was an air-to-ground attack platform,” said Maj. Matthew Mutti of the 104th. “Its primary mission was to provide close air support and provide combat search and rescue capabilities to the soldiers on the ground. The A-10 was designed around a primary cannon, which was designed to engage ground targets.”

The F-15 is a fighter jet designed around a large, forward-facing radar that enables the pilot to see targets in the open sky from miles away. Mutti said. It flies at Mach 1.8, while the A-10 flies much slower at 0.7 Mach.

“With those differences in missions, you can see how the training in each platform would differ greatly,” he said. Ninety percent if the A-10’s training was performed at lower altitudes, 5,000 feet and below; 70 percent of F-15 training is performed at above 12,000 feet, Mutti said.

“Occasionally, the F-15 will practice tracking objects at lower altitudes and over the terrain,” he said. Those training missions could require use of the Condor Military Operating Area airspace — 200 square miles of western Maine stretching from Hartford to Greenville. “But predominantly, their training is performed over the water, whereas the A-10 performed most, if not all, its training over the ground.”

Currently, military operations in Condor are limited to altitudes of between 7,000 and 18,000 feet, but the Air National Guard has applied to the Federal Aviation Administration for permission to lower the Condor operating floor to 300 feet.

Asked whether the 104th’s conversion to F-15s relates to the Air National Guard’s proposal for a lower training floor, Mutti replied: “The mission at the 104th currently is to provide air dominance with the F-15 fighter, which is designed to perform air-to-air missions.”

He said the Condor airspace allows for “overland, low-altitude intercept training, which enhances the training opportunities for our pilots, allowing for increased capabilities (and) proficiency.”

F-16 Falcons from the Vermont Air National Guard’s 158th Fighter Wing in Burlington also use the Condor airspace, Mutti said. The F-16 is a “multi-role” fighter, with both an air-to-ground and an air-to-air mission.

For people who do not live under Condor, the 104th’s conversion will likely mean quieter skies.

A-10s, because of their relatively slow speed — less than 250 knots — were not confined to military training routes and could operate wherever general aviation is allowed. The F-15s will be confined to those designated airspaces.

(Next week: An update on the Air National Guard’s proposal to lower the Condor operating floor.)