Aircraft Noise: Better Information Sharing Could Improve Responses to Washington, D.C. Area Helicopter Noise Concerns, Report to Congressional Requesters [open pdf - 6MB]
From the Highlights: "Helicopter noise can potentially expose members of the public to a variety of negative effects, ranging from annoyance to more serious medical issues. FAA [Federal Aviation Administration] is responsible for managing navigable U.S. airspace and regulating noise from civil helicopter operations. Residents of the D.C. area have raised concerns about the number of helicopter flights and the resulting noise. GAO [Government Accountability Office] was asked to review issues related to helicopter flights and noise within the D.C. area. Among its objectives, this report examines: (1) what is known about helicopter flights and noise from flights in the D.C. area, and (2) the extent to which FAA and helicopter operators have taken action to address helicopter noise in the D.C. area."
Government Accountability Office: https://www.gao.gov/