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OCR for page 119
CHAPTER 8
Noise Abatement
(Airside) Techniques
The results of the airport noise officer survey conducted early during the data collection stage
of this study sought information regarding the activity or offender most frequently complained
about by the public during their conversations with airport staff about noise issues. These find-
ings were verified through follow-up discussions with nearly 30 airports, users, and community
advocates representing airports with a wide range of missions appropriate to the United States.
Note that all results of the survey may be found in the accompanying Toolkit as 8-1
Noise Complaint Characteristics
The frequency of the occurrence of eight distinctly different aircraft activity effects, as cited by
the survey airports, is reflected in Figure 8-1. The number of responses within each of six frequency
categories was weighted to provide a measure of the relative incidence of each type of aircraft
activity as a complaint or concern, as cited by the respondents. The frequencies were: "never"
(0 points), "rarely" (1 point), "occasionally" (2 points), "commonly" (3 points), "frequently"
(4 points), and "very frequently" (5 points). The same categories also apply to the subsequent two
figures. Respondents were allowed to self-regulate their selection based on their perception of the
importance of each category to the conditions at the local airport facility and its environs.
· The combination of too low, too loud, and too many combined to dominate the frequency of
noise complaints received by airports and were the principal source of concern within com-
munities as expressed by non-airport interviewees. Noise complaints citing one of these three
activities occurred more than "commonly" for the group.
· Of more limited frequency ("occasionally" to "commonly") were complaints about nighttime
operations, loud landings and aircraft off expected courses.
· Activity on the ground (run-ups, taxiing, reverse thrust, and ramp noise) were seldom men-
tioned. This may reflect the fact that the loudest noise from these activities generally remains
much closer to the airport and over more compatible land uses than the noise of aircraft in flight.
Responses to questions about the types of annoyance persons cite in their noise complaints indi-
cated a less specific focus on what activity was disrupted than the identification of the aircraft activ-
ity that disrupted it. On average, no individual category of effect was cited more frequently than
"commonly". Figure 8-2 indicates the subject of complaint most cited as annoying to the public.
· Awakening (sleep disturbance) was the most frequently cited public activity disrupted by air-
craft noise, averaging only slightly less frequency than complaints about nighttime operations
(see Figure 8-1).
· The disruption of outdoor activity, speech and classroom activities are cited "occasionally" or
less. This appears to be an inconsistency with the frequent citation of too low and too loud air-
craft, the principal sources of Lmax noise levels that cause these disruptions.
119
OCR for page 120
120 Aircraft Noise: A Toolkit for Managing Community Expectations
Weighted
Frequency Noise Complaint Type
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
Other ground Run-up Aircraft off Landings too Nighttime Too many Takeoffs too Aircraft too
noise (taxi, activity course loud operations overflights loud low
runway,
ramp, etc.)
Aircraft Activity
Figure 8-1. Aircraft activity generators of noise complaints.
· Concerns about vibration correlate well with the complaints about run-up activity and other
ground operations. This is not unexpected because more low frequency noise the source of
most vibration and rattle effects occurs during ground based activity.
The recently published document "Aircraft Noise Effects" (145) describes in some detail the
volume of literature and current understanding associated with the disruption of several differ-
ent types of activity associated with aircraft noise events.
As most airports canvassed for the survey were air carrier facilities with additional uses by
cargo and general aviation operators, it is not surprising that commercial passenger jet activ-
ity was cited most frequently as the source of the noise about which complaints were received.
Figure 8-3 shows the frequency with which complaints in which each of five user groups are
identified as the source of the complaint.
Weighted
Frequency Annoyance
3.00
2.50
2.00
1.50
1.00
0.50
0.00
Classroom Vibration and Speech Disrupts outdoor No relief Awakenings
disruption rattle effects disrupted activities (incessant
exposure)
Activity Disrupted
Figure 8-2. Activities most frequently cited as disrupted by aircraft noise.
OCR for page 121
Noise Abatement (Airside) Techniques 121
Weighted
Frequency Aircraft Source Group
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
Propeller aircraft Helicopter Business jet Cargo jet activity Commercial
activity operations activity passenger jet
activity
Aircraft Group
Figure 8-3. Aircraft groups most frequently cited in noise complaints.
While noise complaints are not considered by the FAA to be a measure of compatibility in noise
abatement planning, their analysis provides insights into the issues that are most important to the
individuals who reside in areas exposed to aircraft noise. This chapter will review a series of oppor-
tunities that the airport manager may choose to investigate with airport users and the FAA in seek-
ing to moderate any adverse impacts aircraft noise may have on the airport's neighbors. While
conducting these investigations, many airports have found it helpful to involve the neighbors in
seeking out various approaches to mitigate noise. By doing so, the neighbors become better aware
of the constraints faced by all parties to the management of aviation conditions, and better under-
stand that any improvements or resolutions to the situations they perceive to be of significant
impact must be the result of a give-and-take process accepted by all parties.
The remainder of this chapter provides a description of various noise abatement techniques
currently in use to mitigate aircraft noise levels. These include airside measures, which are actions
that the airport, air traffic control, or the aircraft operators may take to reduce the impacts of air-
craft noise on populations under the routes of flight. The goal of a noise abatement action is the
reduction of the number of persons exposed to environmentally significant levels. The FAA cur-
rently defines that level as being 65 decibels of DNL. However, many communities around the
United States are establishing additional noise level criteria for land use management that extend
to areas beyond the 65 DNL level to reduce or control the introduction of newly impacted persons.
The benefit or disbenefit of every noise abatement action is a function of the residential pop-
ulation and number of nonresidential noise-sensitive uses that fall within the noise patterns
resulting from implementation of the measure. If the population is not distributed evenly across
the area affected, certain specific opportunities may be present to design noise abatement
actions. When the population is broadly spread, other actions may be capable of producing the
most effective results. The distribution of the noise pattern over the distributed population is the
key to finding the mix of various tools for aircraft noise abatement and land use control to max-
imize the reduction of noise impacts while taking into account the continuing utility of the air-
port's role as a transportation center. The application of noise abatement actions, particularly if
restrictive in nature, may generate a substantial effect on airport delay and flight time, and may
potentially hinder airport expansion. The next chapter will review land use management tech-
niques that may be used for airport noise compatibility planning.
