Glossary

In alphabetical order

A

AENOR
Spanish standardisation and certification association
Apu
“Auxiliar power unit”. Unit for the production of power independent to the aircraft.

C

Chap 2
Chapter of Annex 16 of the ICAO, where a classification is established for aircraft with must noisier engines.

D

dB (A)
Decibels in weighting A.

E

Equivalent continuous level
Noise level generated by any source, measured in decibels.

I

ICAO
International Civil Aviation Organisation.

L

Leq(A) plane
Equivalent Continuous Level that would have been generated were there not more noise than that produced by the planes in weighting A.
Leq(A) day
Continuous equivalent level corresponding to the daily period, from 07:00 to 22:59 h.
Leq(A) night
Continuous equivalent level corresponding to the nighttime, from 23:00 to 06:59 h.
Leq(A) total
Equivalent Continuous Level generated by all sources of noise in weighting A.

N

NL
Noise level of each airline according to which it can plan its operations according to the aircraft noise certificate.

O

OFIMA
Environmental Information and Service Office.

P

Percentile L10
Statistic value representing the level in dB(A) that has been equalled or exceded for 10% of the time.
Percentile L50
Statistical value representing the level in dB(A) that has been equalled or exceeded for 50% of the time.
Percentile L90
Statistical value representing the level in dB(A) that has been equalled or exceeded for 90% of the time.

S

SCVA
Visual and Acoustic Control System.
SIRMA
Noise and flight path monitoring system.

T

TMR
Noise monitoring terminal made up of a microphone and computer support.

W

Weighting A
Frequency filter similar to that perceived by the human ear.