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Santa Monica ~fornia, July 8, 1977
TO'
~myor and Clty CounCll
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FRO~I:
Clty Staff
SUBJECT:
Reduction of ~oise Limits at Santa Monica Airport
Introduction
This report reviews the elimination of night flight operations and reduc!ion of
00'< RcwvedjlJl 1 1 ~~( I
current noise limit restrictions at Santa !>lonica Airport.L'-: -I.. n~'cornmends tne elimination
of night flIght operations at the alrport.
Do"o D:'M'5;~
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Backp-ound
Pursuant to the Joint meetlng with the Airport CornmissTon'.o'(lurtrrg-Uecerfi5er 1971>,
C::;"'e C~li""Er~d
To A"'y
the City Council requested that the Staff complete an analysis of:
1. The effects of reducing the current 100 db SENEL (Single Event Noise
Exposure Level) limit to 90 db SE~~L for all fllghts; and
2. Prohibiting all take off and landing operations between the hours
of 11:00 p.m. and 7:00 a.m.
Reduction of SE~"EL limits from 100 db to 90 db
In order to accurately assess the impact of reducing the SE~~L limit from 100 db
to 90 db, Staff isolated all flights that registered over 85 db on the Airport
~olse Monitoring System for a period of four months, and placed them in 5 db
intervals ranging from 85 db to 90 db, 90 db to 95 db, and 95 db to 100 db. The
summation of this data as depicted in Table I indicates that a reduction of noise
levels to the 90 db level would result in the ellmlnatlon of an average or 2.72% of
all flight operations at Santa ~onica Airport.
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To:. 1-1ayor and City Cot. -.
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July 8, 1977
TABLE I
85-90 90-95 % 95-100 % 90-100 % Total I
db db db db Operat~ons
August '76 12 518 1.9 140 .5 658 2.44 26,965
February '77 18 424 2.1 101 .5 425 2.58 20,343
Apnl '77 1370 676 2.76 138 .56 814 3.33 24,428
!>lay '77 49 528 2.0 119 ,46 647 2.52 25,645
Average percentage of total operat~ons for flights
between 90 - 100 db = 2.72%
The Communlty ~oise Level Effect of Elim~nating Flight Operat~ons Over 90 db
In general, if nOlse events such as alrcraft flyovers are lnfrequent, the peak nOlse
level of lndivldual events wlll in most cases determ~ne individual reactlons to that
noise. However, if the nOlse events are relatively continuous, the cumulatlve no~se
exposure becomes the more important factor In gaug~ng cornmunlty or resldents'
reactions to alrcraft noise. In reviewing the data ~n Table I for perceptlble
CNEL (Cumulative Noise Exposure Level) effect, Bolt, Beranek and Newman (nOlse
consultants), proJected that by reduclng the CXEL l~mit to 90 db, a 1 to 3 db effect
could be achleved. In terms of community noise level (C~EL) reduction. it lS Bolt,
Beranek and Newman's opinion that a 1 to 3 db CNEL decrease would be of marginal
consequence in lowerlng the perceived nOlse levels for residents in the immedlate
vicinity of the A1Yport.
Bolt, Beranek and Ne~~an substantlated this analysls by citing the example of
an experiment conducted in Inglewood. In this experlment, even though the moving
and adjusting of nlght fllght patterns resulted In a 2 db C~EL effect, the docunented
Te. ~ l>fayor and City Cot. ..
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July 8, 1977
resldent response showed that the great ma]Orlty of residents had not notlced
any change. Further, dunng discussions with Staff, UCLA Professor Bill Heecham,
ACoustlcal Engineer, also expressed doubt that ellminatlon of 2.72% of operations
conslsting of flights in the 90 db to 100 db range would be substantial.
Reactlon to aircraft noise lS a combination of frequency as well as level. It is
Staff's bellef since total operations between 90 and 100 db amounts to 2.72% of
total fllght operatlons, any noise level reductlon accompllshed by ellmlnating
those operations will provlde limlted rellef to residents in terms of perceived
communlty noise level. The extent of rellef will depend on the indivldual's
locatlOn to the alrport and psychologlcal response to various levels of nOlse.
Financlal Effect of Eli~inating Flight Operations Over 90 db
Of the 440 airplanes currently tied down at Santa Monlca Airport, a 90 db
restrlction could exclude up to approxlmately 50 tWln englne and 25 single engine
aircraft (combined estimated value -- $1,000,000). In addition, two Gr~~n I
turbo-prop alTcraft (combined estimated value -- 54,000,000), o~~ed by Lear-Slegler,
Inc. and Hilton, Inc. would also be elimlnated. The resultant financla1 loss to
the City is estimated as follows:
Aircraft Petroleli~ Sales (net proflt)
Aircraft Tiedow~ Rentals
Hangar T-201 Rental to Lear Slegler, Inc.
Aircraft Tax (property)
TOTAL:
$20,000 per year
15,000 per year
18,000 per year
25,000 per year
$78,000
It should be noted that L~e loss attributed to tiedow~ rental revenue would be
mlnimized as vacanCles are filled by replacement from new customers.
To;. t-layor and City COl. -.
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July 8, 1977
The above figures represent dlrect estlmated alrport revenue losses to the City,
and do not include losses that ~ay be suffered by airport fixed base operators.
The projected losses for the fixed base operators was not made available to the
City Staff, however, all operators were contacted and several ind1cated that
losses would be substantlal.
Review of Lowering SENEL (Single Event Noise Exposure Level) Limits at Santa
Monica Airport
The pr1mary considerations in determining the feas1bility of reduc1ng the SE~EL
11mits are community benefit (CNEL effect) in terms of perceived noise level
reduction, and financial 1mpact on A1rport operat1ons. Bolt, Beranek and Neh~an
suggest that a ~1nimum C~L effect of 5 dbs is required to achieve a perceptible
improvement in community nOlse levels. Both SENEL and CNEL (Commun1ty ~oise Exposure
Level) are measures of A-weighted sound levels, a scale that suppresses low
frequency noises much like the human ear. The db(a) scale is used to assess noise
power or pressure levels, either as a s1ngle event 1n the case of SENEL or as a daily
community noise equivalent level, C~EL. The accumulat10n for C~~L is adjusted to
give more weight to the noise occurring between 1900 and 2200 hours and most we1ght
occurring between 2200 and 0700 hours. Consequently, mere reduction In SENEL does
not necessarily guarantee an overall percept1ble C~EL affect. A primary example is
the data gathered by Staff in exploring the poss1b1lity of reduc1ng the db level from
100 to 90.
The fact that the perceptlble annoyance level of 1ndividuals is related to both
frequency of events and percelved loudness of indivldua1 events suggests that a more
positive CNEL effect may be achleved ln Santa Monica from combin~ng levels of SEN~L
reduction with other Airport operatlng limitations. such as restricted pattern flYlng
and/or touch-and-go hours; the CNEL effect would exceed 5 dbs.
To ~ Mayor and C1 t)' Cou -.
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July 8, 1977
Therefore, in view of the above and the determlnation that a fully pe~ceptlble
C~EL effect cannot be attained by reducing the SEXEL llmits by 10 db, Staff
bel1eves that a more complete study is necessary to determlne the necessary
combinatlon of n01se restrl~tions to accomplish a perceptible effect. The
analysis would lnvolve the followlng research activity:
1. Programming of current nOlse monitoring system to prlnt out all
flights over 70 dbs for a four month period. This would allow
Staff to determine specifically what level db reduction would
generate a posltive C~~L effect.
2.. Programmlng of current noise monitoring system to compute
CNEL effect on a dally basls. This would assist Staff ln
projecting the effect of pattern flying restrictions, touch-
and-go restrictions and conversion of SENEL reduction to CNEL
effects.
3. Analysis of costs to City and fixed base operators of any
nOlse reduction program lncorportating further SE~cL restrlctions
and/or other airport operatlon limltations.
Prohibltion of Take-Off and Landing Operations Between 11:00 p.m. and 7.00 a.m.
Evaluatlon of the data pertaining to nlght fllghts as displayed in Table II below
indicate that while nlght operations consist on the average of only .68% of total
monthly Airport operations, almost 80% of all night flights fall lnto the 90 to
100 db range.
To:' ~layor and City Cou. -.
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~ July 8, 1977
TABLE II
Total 90-100 db night flights
85-90 90-95 95-100 N1ght as % of as % of total
db db db Operat1ons total n1ght operatlon
operations
August '76 58 16 74 100% .2i%
February , 77 10 59 15 84 88% .41%
A.pr i1 '77 120 97 52 366 40.7% 1.5%
May '77 13 103 26 142 90.8% .55%
Average percentage - total night operation for flights between 90 db - 100 db 79.E
Average percentage - n1ght fl1ghts as % of total airport operat1ons .68%
On the basis of this data, the effect of restrlcting n1ght fl1ghts to the 90 db
SENEL llm1t would be to drop the average SENEL db per nlght flight from approximately
92.2 dbs (weighted average) to a projected weighted average of 86 to 88 dbs SE~L.
In db(a) weighted measurement a 5 db reductlon is equivalent to 40% reduction in
perceived noise. Consequently, Staff believes that a substantial noise level lmprove-
ment would be achieved by reducing SE~cL limits for n1ght fllghts from 100 db to
90 db.
Enforcement
Currently the City has no enforcement of 100 db SENEL vlolations committed at night
when the fl1ght tower is closed although the data lS recorded by noise monitoring
equlpment. If a 90 db restriction is 1mposed for night flights, v1o1ations would
~:
~Byor and C1~y coun~
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July 8, 1977
be more prevalent and enforcement would requlre SOph1s~lca~ed nOIse monItoring
equipment and attendant personnel. Minimum costs for equipment and personnel
would exceed $30,000 for the first year and $20,000 for subsequent years. In order
to circumvent costs related to enforcement of n01se violations, Staff recommends that
all nlght flight operatIons at Santa Monica Airport be eliminated durIng the hours
of 11:00 p.m. and 7:00 a.m. Enforcement would be carrled out by eXIsting guard
personnel unless this proved to be insufficlent in practice.
FinancIal Effect of Restricting all Flights Between 11:00 ~.~, and 7:00 a.m.
~~ile several aircraft operators have 1ndlcated a preference for 24 hour access to
the A1rport, it is Staff's opinion that elim1nation of fllghts between 11:00 p.m.
and 7'00 a.m. would not cause an undue burden for most operators. Potential losses
In gasoline sales should not exceed $5,000 annually.
Alternatives
I. Reduction of SE~~L limits from 100 db to 90 db
1. Do not approve any change in the current 100 db lImit until
further staff analysis 1S completed -- This alternative recognIzes
that in additIon to further data breakdown of all flights over 70 db
for the purpose of determining a reduced SE~L lim1t that would produce
a more beneficial CNEL effect, improvement in the C~EL level ~ay also
be achieved by comblnlng lower SE~~L restrictions with other operational
limitations such as restricted pattern flying. This analysis would also
have to include the financial effect of such action.
2. Impose restrict~on of 90 db -- Analysis of data collected by staff 1ndicates
that a 10 db reduction in SENEL would eliminate 2.72% of the total
airport fllght operatlons, wlthout prov1dIng substantlal C~EL reductions.
To.
Mayor and City coun~
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July 8, 1977
II. Prohib1tion of Take-Off and Landing Operat1ons Between 11:00 p.m.
and 7: 00 a . m.
1. Prohibit all nIght fllghts between 11:00 p.m. and 7:00 a.m. -- This
a1ternat1ve 1S most acceptIb1e in that It would allev1ate the noise
problem for ~lrport residents durIng the nIght hours and should not
requ1re additIonal expenditure for enforcement.
2. Restrict night flYlng to 90 db SE~~L -- This alternative is less
desirable due to the dlfficulty and expense ($30,000) that would be
Incurred as a result of attemptlng to enforce this ordlnance.
3. MaIntain current night flight operatIons with no restrlctions
This alternatIve would, of course, result In no change in the nOIse
level of the airport.
Recornmendat ions
1. Staff recommends that the City Councll approve alternative n~~ber 1 in re1atlon
to reduction of SE~EL lImIts from 100 db to 90 db. ThIS would authorize the
City Staff to complete analysis of flight data over the next four months with
the objective of outlining to Councll a method of noise reductIon WIth speclflC
costs to the Airport and A1rport operators. This report would be provided to
Council by December 1977.
2. Staff recOmflends that Council approve alternative 1 relating to prohibItion of
take-off and landing operat1ons between 11:00 p.m. and 7:00 a.m. This alternative
would eliminate all n1ght flights at Santa ~wnIca Airport durIng those hours
and request that the City Council authorIze the City Attorney to draft an
ordinance for flrst reading,
Prepared by' Larry J. Kosmont
AdministratIve Assistant
LJK:pp
CA 77-99 RLK:SIS'-'k 7-29-77
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For Counell Mtg: 8-9-77
ORDINANCE NO.
(Clty Councll Serles)
AN ORDINk~CE OF THE CITY COlWCIL OF
THE CITY OF SANTA HONICA AHENDING
SECTION 10101 OF THE SANTA MONICA
MUNICIPAL CODE, RELATING TO TAKE-OFF
AND LANDING OPERATIONS OF AIRCRAFT
BETWEEN 11:00 O'CLOCK P. M. AND
7:00 O'CLOCK A. M.
THE CITY COu~CIL OF THE CITY OF SANTA MONICA DOES
ORDAIN AS FOLLOWS:
SECTION 1.
Seetlon 10101 of the Santa Monlca
Mun1Clpal Code lS hereby amended and shall read as follows:
Seetlon 10101. HOURS. The a1rport
shall be open for publlC use at all reason-
able hours of the day and nlght, subJect to
such restrlctlons as are provlded hereln or
are due to 1nclement weather, the condltlons
of the land1ng area, the presentatlon of
speclal events and llke causes, as may be
deterffi1ned by the alrport dlrector; provlded,
however, that no person shall take-off or make
anythlng other than an emergency land1ng of
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any alreraft from or at the alrport between
the hours of 11:00 o'clock p. ill. of one day
and~'eloek a. ffi. of the next succeedlng
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day. The alrport dlrector, or ln hlS absence
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the watch commander of the Santa Monlca pollce
Department, may approve a take-off durlng sald
hours, provlded lt appears to h1S sat1sfactlon
that an emergency lnvolvlng Ilfe or death eXlsts
and approval 15 obtalned before take-off.
SECTION 2. Any provlslons of the Santa Monica Munlclpal
Code, or appendlces thereto 1nconslstent herew1th, to the extent
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of such ~ncons~stencles and no further, are hereby repealed
or modif~ed to that extent necessary to effect the prov~slons
of th~s ord~nance.
SECTION 3.
If any sect~on, subsectlon, sentence,
clause or phrase of thlS ordinance lS for any reason held to
be ~nval~d or unconst1tut1onal by a declslon of any court of
competent Jur~sd~ctlon, such decls10n shall not affect the
valld~ty of the rema~n~ng port~ons of the ord1nance. The
C1ty Councll hereby declares that ~t would have passed thls
ord1nance and each and every sectlon, subsect~on, sentence,
clause or phrase not declared lnval~d or unconstltut~onal
wlthout regard to whether any portlon of the ordlnance would
be subsequently declared lnvalld or unconstltutlonal.
SECTION 4.
The !1ayor shall s~gn and the Clty
Clerk shall ~ttest to the passage of thlS ordlnance. The
Clty Clerk shall cause the same to be publlshed once In the
offLclal newspaper wLthln flfteen (IS) days after its adoptlon.
The ordlnance shall become effect1ve after thlrty (30) days
from ltS adoptlon.
ADOPTED and APPROVED thls
day of
1977.
HAYOR
ATTEST:
CITY CLERK
STATE OF CALIFORNIA
COUNTY OF LOS ANGELES ss.
CITY OF S&~TA MONICA
I do hereby certlfy that the foregolng ordlnance was
duly and regularly lntroduced at a meeting of the City Councll
on the
day of
, 1977; that thereafter the
sald ordlnance was duly adopted at a meetlng of the C1ty
COUDCll on tDe
day of
, 1977; by the
followlng vote of the Councll:
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CA RLK:SIS:]ak .
AYES:
COUNCIU1EHBER:
NOES:
COUNCILMEl'1BER:
ABSENT:
COlNCILl<1EivlBER:
4t
CITY CLERK
')PP~OVED AS T~ro',
~y
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