Acoustic Propagation & Decay Curve
Distance vs Decibels (dBA)High (Exceeds WHO outdoor daytime threshold of 55 dBA)
Acoustic Propagation Engine • NYC Heliports to East End Corridors
High (Exceeds WHO outdoor daytime threshold of 55 dBA)
Sound pressure drops with spherical spreading following \( 20 \log_{10}(d / d_0) \) combined with atmospheric molecular absorption (~1.5 dBA per 1,000 ft at 20°C/60% RH) and ground attenuation effects over mixed coastal foliage and pine barrens.
Helicopter rotor noise contains low-frequency impulsive blade-slap that readily penetrates residential exterior walls, yielding higher indoor annoyance and rattling fixtures even when overall A-weighted sound attenuates by 24 dB through closed double-pane windows.
FAA North Shore Route mandates 2,500 ft over water, yet transitions inland over Sag Harbor, Noyack, and Wainscott routinely descend below 1,500 ft into East Hampton Airport (JPX), sparking ongoing local curfew and diversion disputes cited by WSJ reports.