INM 5.1 technical manual

FAA-AEE-97-04

Manual

Final Jan 93 - Dec 97

United States. Federal Aviation Administration

NTL-AVIATION-AVIATION ; NTL-AVIATION-Aviation Energy and Environment ; NTL-ENERGY AND ENVIRONMENT-Aviation Energy and Environment ;

The Federal Aviation Administration, Office of Environment and Energy (FAA, AEE-120)

has developed Version 5.1 of the Integrated Noise Model (INM) with support from the

John A. Volpe National Transportation Systems Center, Acoustics Facility (Volpe Center)

for development of the acoustic computation module and from the ATAC Corporation for

systems integration, development of the graphical interface, and methods for computing

aircraft flight profiles and constructing flight paths, which are processed by the

acoustics module.

The Technical Manual for INM 5.1 describes the flight-path methodology (Chapter 2),

along with the basic methodology employed by the INM to compute a noise-level or timeabove

metric at a single, user-specified observer, or at an evenly-spaced, regular grid

of observers (Chapter 3).

The noise/time computation methodology is presented in a concise step-by-step fashion,

and includes a description of: (1) the computation of the flight-segment geometric and

physical parameters; (2) the flight-segment noise-level interpolation process; (3) the

acoustic impedance adjustment; (4) the flight-segment noise-fraction adjustment for

exposure-based metrics; (5) the airspeed adjustment for exposure-based metrics; (6) the

lateral attenuation adjustment; (7) the ground-based directivity adjustment for

observers behind start-of-takeoff-roll, as well as for computing metrics associated

with runup operations; (8) the metric computation process; and (9) the development of a

recursively-subdivided irregular grid methodology, which is used for computing noise

contours (Chapter 4).

PDF

Volpe National Transportation Systems Center, Technical Reference Center