Effective Perceived Noise in decibels is the metric used to certify aircraft noise. It weights the sound for human perception and duration, including the annoyance of tonal components, so it captures how loud an aircraft actually seems rather than raw sound pressure alone.

What are the three measurement points?

Lateral or sideline is measured beside the runway during takeoff at the point of maximum noise. Flyover is measured under the departure path after the aircraft has climbed. Approach is measured on the glideslope before landing. An aircraft must meet a limit at each.

How do ICAO Chapters relate to FAA Stages?

They are parallel systems for the same standards. ICAO Annex 16 Chapter 3 matches FAA Stage 3, Chapter 4 matches Stage 4, and Chapter 14 matches Stage 5, which is the strictest current standard. A modern airliner is typically Chapter 14 or Stage 5.

What is the cumulative margin?

It is the sum of the margins to the limit at all three measurement points. Modern rules like ICAO Chapter 4 and Chapter 14 require an aircraft to be a minimum number of cumulative EPNdB below the older Chapter 3 limits, so the cumulative margin shows compliance headroom.

Aviation Noise Exposure Reference Tool

Q: Are these values exact for compliance work?

No. The figures are representative levels and the limits shown are illustrative for a mid-size jet, because real ICAO Annex 16 limits scale with maximum takeoff weight. For certification or airport compliance work, always use the official type-certificate data sheet for the specific aircraft.

Aircraft are certified for noise, not just performance, and the rules use a specific metric and a tiered classification. This reference looks up the certified EPNdB noise levels and the ICAO Chapter / FAA Stage category for common aircraft types, and explains the three measurement points behind the numbers.

How it works

Every certified aircraft is measured at three points and compared to a weight-based limit at each:

lateral / sideline → maximum noise beside the runway during takeoff
flyover            → noise under the departure path after climb
approach           → noise on the glideslope before landing
cumulative_margin  = Σ (limit − measured) over the three points

ICAO Chapter 3 equals FAA Stage 3, Chapter 4 equals Stage 4, and Chapter 14 equals Stage 5, the strictest current standard. Modern rules require a minimum cumulative margin below the Chapter 3 limits, which is why the tool sums the per-point margins.

Example

A modern narrowbody such as the A320neo is certified to Chapter 14 / Stage 5, with flyover noise in the mid-80s EPNdB — substantially quieter than a Chapter 3 widebody quad, whose flyover noise can exceed 100 EPNdB. The cumulative margin makes that gap a single comparable number.

Notes

The values here are representative and the limits are illustrative for a mid-size jet; real ICAO Annex 16 limits scale with maximum takeoff weight. For certification, airport access, or noise-charge work, always use the official type-certificate data sheet for the exact aircraft variant. All lookups run locally.