Scores of residents in the Hailey-Bellevue area complained to Friedman Memorial Airport officials and the Blaine County Sheriff's Office about pre-dawn engine tests conducted early Monday on a Horizon Air Q400 turboprop airliner.
A spokesperson for Horizon said a cockpit warning light on Flight 2343 departing Sunday for Los Angeles indicated a malfunctioning part that required replacement. Mechanics drove in from Boise, replaced the part, and then taxied the aircraft to a ramp area where engines could be run up at maximum rates.
The episode occurred about 2:30 a.m. Callers estimated the noise continued between 15 and 45 minutes.
Friedman Manager Rick Baird said Horizon did not notify airport officials prior to the tests. He said the pre-dawn maintenance check was unusual—only about the fourth or fifth such event he can remember in 15 years.
"It was an inconvenient hour," Baird said of the tests. "It should have been coordinated with us."
As for the disparity in estimated times of the noise, Baird said residents closer to the field probably first heard the 70-plus-passenger aircraft's auxiliary power unit, a small on-board engine that provides independent power for electrical, hydraulics, pneumatics and ventilation. The actual run-up of turboprop engines probably lasted less time.
Though Friedman has a voluntary noise-abatement program, as a 24-hour airport it has no authority to close the airport to aircraft activity.