570 likes | 723 Views
Noise or Annoyance?. Is actual jet noise a problem? Or is the problem only present in complaints?. Public discourse and public policy determine public perception. If public agencies treat something as a problem, the public perceives it as a public problem, even if it is not.
E N D
Noise or Annoyance? Is actual jet noise a problem? Or is the problem only present in complaints?
Public discourse and public policydetermine public perception.If public agencies treat something as a problem, the public perceives it as a public problem, even if it is not. Why this is important to APAC:
Approaches as portrayed by vocal critics: A300-600 freighter, photographed off end of Runway 22L, camera lens zoomed to 200 mm. Actual Approaches over EDH: A300-600 freighter, photographed from Ridgeview, at the point of minimum altitude above ground level in EDH Camera lens at 55 mm, matchingperspective of human vision
Fundamentaltypes of issues: • Objective factors-- Shared by everyone • Subjective factors: Annoyance-- Generally not shared by everyone
Objective Factors • Regulatory: CNEL noise (Community Noise Equivalent Level),required by state to be no more than 65 dB CNEL • Single event noise: SEL, Lmax:This depends mainly on aircraft altitude and descent rate:On a standard 3-degree glide slope throttle setting isapproximately at flight idle. • Number of EDH overflights per day:Four (4) overflights are typical in May, 2013on cargo-busy days of the week.
Major Subjective Factors • Personal factors • Social factors • Subjective perceptions of objective factors All of these combine to produce Annoyance. A large body of research has shown that personal and social factors often are totally unrelated to objective factors. At least half a century ago researchers began developing and using metrics to associate actual measures of noise with observable measures of annoyance, including complaint rates for jet noise. These slides use one such measure, the NNI index.
Sanity Checks: How does our situation compare with somewhat similar ones elsewhere? • Objective factors • Subjective factors: Annoyance
Homeowners reportingno jet noise problem + From personal contact while measuring actual noise levels + + + 2 of 2 + + 4 of 4 homeowners contacted at point of Maximum noise in El Dorado Hills
Highly vocal critics claiming noise problems:Distance from home to approach path This data is retained from an earlier year, Individual critics may have moved. In most locations of El Dorado Hills approach noise cannot be discerned fromambient background noise it distances of about 1¼ miles plus or minus ¼ mile.
GoldLine: Mather 22L ILS course Red Line: 4.09 miles, shortest distance from home of serial complainer in Shingle Springs to Mather 22L ILS course
Red shading: Aproximate area in which an air carrier cargo aircraft approach generally is audible, though sometimes is inaudible at the edges.2.0 miles wide, 1.0 mile either side of center. Yellow shading: Approximate area in which an approch can be barely audibledepending on conditions.
Typical UPS arrival via Hangtown VOR, Turning onto Mather 22L ILS course at CAMRR Home of serial complainer Minimum separation of approachfrom home of serial complainer in Shingle Springs is 4.09 miles.
Specific claims & measured reality • Claim: A serial complainer in Shingle springs says he routinely experiencesnoise of 80 – 90 dB at his home. • Fact: His home is 4.09 miles from the nearest point on the standardapproach paths currently in use. Approach noise from these aircraftdrops below the limit of human perception at a slant distance ofabout 1.5 miles.An example was a Board Of Supervisors Town Hall meeting in 2007at the EDH Senior Center. This is 1.2 miles from the nearest point beneaththe ILS approach to Mather Runway 22L. A 757-200 freighter passed byabout 5 minutes before the meeting started; no one noticed the freighterexcept me. I noticed because I saw it while parking my convertiblewith the top down.
Specific claims & measured reality • Claim: A serial complainer in Shingle springs says he routinely experiencesnoise of 80 – 90 dB at his home. [repeated to consider sound levels] • Fact: The loudest noise level occurs directly beneath the aircraftat its minimum crossing altitude above ground level. In El Dorado Countythis is at a particular location on Ridgeview in El Dorado Hills. • Fact: Typical measured maximum instantaneous noise levels (Lmax)beneath aircraft crossing Ridgeview in EDH are in the range of 66 to 68 dBA.This is a level usually associated with quiet conversation at 3 feet.It is also the typical level in Board of Supervisors meetings. • Fact: The loudest approach I have ever measured in El Dorado Countyproduced a maximum of 74 dBA at Ridgeview. • Fact: The loudest approach noise I’ve measured anywhere was 84 dBA.Multiple measurements showed this for 747-400 airliners on approach to SFO, about 1,800 feet above ground level at Foster City. SFO normally has a far lowerrate of complaints than is produced by our area’s serial complainers.
Sanity Checks: How does our situation compare with somewhat similar ones elsewhere? • Objective factors • Subjective factors: Annoyance
Questions… For major objective factors: • What sound levels do freighter approaches actually produce on the ground? • How much traffic (approaches per day over EDH/Folsom) is there? When? • How will these measures change in the future? • How do complaints about noise relate to actual noise? • What misconceptions are evident in complaints? • How do public agencies affect public perception?
Not for navigation [Not a current IFR chart]
Mather ILS vertical profile Not for navigation [Not a current IFR chart]
CAMRR 6,500 LDORR 5,000 YOSHE 3,000 Nominal ILS Approach
Nominal ILS Approach EDH East Ridge 4,600 EDH West Ridge 3,900
ILS intercept @ LDORR Plus a burst of afternoon traffic
VFR approach South of US 50
Loudest 2008 freighter approach recorded in WebTrak: Probably about 85 dBA
Approach from south By UPS954 plus other Traffic (week before Christmas)
Approach Usage Data for the week of December 15 through December 22, 2008 -- The week before Christmas, busiest freight week of the year
Approach Noise Exposure Potential Data for the week of December 15 through December 22, 2008 -- The week before Christmas, busiest freight week of the year
OverflightNoise Measurement Measurements on SierraFoot.org use Lmax, the maximum noise level SEL/SENEL – Oakland, Foster City Lmax, Oakland, Foster City SEL/SENEL, EDH West Ridge Lmax, EDH West Ridge
Actual Crossing Altitudes on ILSat Initial Approach FixRescue area, north of Shingle Springs
Actual Crossing Altitudes on ILSat El Dorado Hills west ridge
NNI Annoyance & Complaint Rate NNI is the first widely accepted index of annoyance due to exposure to jet noise, adopted by the British more than 40 years ago. Published literature, including documents cited by www.keepthepeace.org, indicate that NNI less than 35 corresponds to insufficient annoyance to produce complaints. Values somewhat above, such as Foster City‘s 46.2, are expected to produce sporadic complaints. This table reports a composite complaint rate for Mather-correlated complaints from Folsom, El Dorado Hills, Rescue, and Shingle Springs. All complaint counts are from the first 7 months of 2008.
Can a single serial complainer dominate complaint statistics? Yes -- Here’s an example from LAX, July 2008:
Serial Complainers & MHR Noise complaint statistics correlated with Mather flights also show highly disparate rates depending on the location of complainers. Average monthly complaints : 45 per Folsom caller, 12 per EDH caller
Serial Complainers & SMF Location-specific complaints also apply to noise attributed to flights to and from Sacramento International Airport. Average monthly complaints: 33 per Folsom caller, 8 per EDH caller
MHR serial complaints by community Complaint percentage distribution for SMF is similar, ± 6% per community
SMF serial complaints by community Complaint percentage distribution for MHR is similar, ± 6% per community
Populace in general Most people in the EDH/Folsom area think we have problems with jets flying too low and too loud. The main exceptions are those who live directly under the ILS approach, who generally indicate no problem exists. The public understanding derives mainly from public dialog and media news coverage. Public agency treatment of the issue as a noise problem has carried strong influence – especially in connection with the City of Folsom‘s 2007 law suit.
Random sample:Noise under the ILS, west ridge, EDH – loudest point for Mather approaches Afternoon of August 25, 2009
Remaining slides are excerpts from a typical sessionof observing a freighter approach and measuring itsnoise level from Ridgeview, directly under the approach. First, a web tool (FlyteComm in this case) is used to identify air carrier cargo flightsscheduled and en route to Mather. The screen image shown is for a flight UPS 2958,which did not overfly EDH on this day. A different web tool, WebTrak, was used later to check the UPS 2958 actual flight trackin the Sacramento region. After driving to 3270 Ridgeview Dr, directly below the ILS approach to Runway 22L,while waiting a T-38 and a pickup truck were photographed and their noise measured. UPS 2960, a 757-200, was photographed as it flew over on the ILS approach. The sound level meter reading was photographed after it had latched the maximumsound (pressure) level of 61.7 dBA, roughly half as loud as the T-38 and the pickup truck.
Sample measurement The following sequence of slides shows an example of noise data collection. The aircraft is photographed as it passes, then the noise meter is photographed to record the noise meter’s Lmax reading. Not visible, the camera records date and time. This sample shows a low-noise approach over Ridgeview. Most approaches are in the range of 66 dBA to 68 dBA.