Airspace Reviews, or Obstruction Evaluations, are performed by the MassDOT Aeronautics Division and the Federal Aviation Administration (FAA), respectively, to determine if a type of construction or alteration of a structure in the vicinity of an airport will penetrate an imaginary surface and become an obstruction.
Imaginary Surfaces are three dimensional surfaces surrounding a runway and airport that determine safe altitudes for aircraft approaching or departing an airport. The Commonwealth of Massachusetts defines imaginary surfaces based on Massachusetts General Law Chapter 90 Section 35B and the Code of Massachusetts Regulations (702 CMR). The FAA defines its imaginary surfaces based on Title 14 Code of Federal Regulations (14 CFR part 77).
Obstructions: An obstruction is any object, natural or man-made, that penetrates above the imaginary surface and may interfere with a pilots ability to safely fly an aircraft. Obstructions may be temporary or permanent and some examples include:
- Wind Turbine
- Light/Flag/Utility Poles
- Solar Panels
Public-Use Airport: According to 14 CFR part 77 a public-use airport is “available for use by the general public without a requirement for prior approval of the airport owner or operator.” List of Massachusetts public-use airports