Theairplane is the greatest inventions of the human history at large. Flyinghigher and higher in the air like birds had always been one of the dreams ofhumans since the beginning of time. The continuous struggle by Wright Brothers,and many other flying enthusiasts astounded the world when the dream of flying likebirds became reality. Theaviation industry is experiencing a phenomenal growth, but it is also increasinglyfacing the problems such as environmental issues. Environmental impacts of aircraftsare growing as the demand for flights is increasing. One of the environmentalissues from aviation is noise pollution. The unit to measure noise is calleddecibels.
For human beings, sounds above 85 decibels causes permanentdamage. 18Aircraftnoise affects millions of people all around the world. Community living closerto the airport is affected the most. Airport noise pollution is not onlydetrimental to humans but also to the wildlife. Airplanes generate 150 decibelsduring a takeoff, and this is 10 decibels louder than a gunshot.
There areseveral case studies where children whose schools are near the airport scoredlower on their tests (O’Neil, 2002, F6) and their score significantly improvedwhen they were moved to quieter location. There are several complaints filed bythe community people living near airport who have interference with theirspeech, sleep problems, less concentration power and damage to hearing due theairplane noise pollution. Studies haverevealed a link between increased risk cardiovascular diseases and stroke amongpeople living in areas of regular high noise pollution 13, 14, 15,16, 17. Studyperformed by University of Agriculture and Ardhi University, Tanzania Studentand Professor group shows the measured noise level during a take-off andlanding at different locations (Waiting lounge, Dispensary, School andResidential area) near airport reached average of 64.
55 dBA during landing and63.2 dBA during a take-off. They also collected community response to learncommunity awareness on aircraft noise pollution on their health. 53% of therespondents were aware of the side effects of aircraft noise pollution on theirhealth. This study shows that the noise pollution by airplanes is not only aproblem in USA, but it is there all around the world and, exists at both smalland larger (busier) airports.
Belowfigure shows how humans are affected by long term exposure to noise pollution: Mitigationof aircraft noise:To reduce the noise pollution and itseffects on community, Government of different countries are taking steps forthe betterment of human life. International CivilAviation Organization made a policy on aircraft noise, whichdetails all the elements that can be employed by airport owners to achievenoise reductions. This is known as Balanced Approach to Aircraft NoiseManagement. The Balanced Approach involves analysis of noise problem at aparticular airport and exploring various steps that can be taken to mitigatethe noise pollution using objective and measurable criteria. ICAO BalancedApproach is classified into four parts as shown in Figure 2 below: Figure 2: The fourprincipal elements of the Balanced Approach to Aircraft Noise Management 1.
Reduction of noise at Source: Thefirst noise standard developed by the ICAO Committee to reduce aircraft noisepollution was to estimate noise limits as a direct function of Maximum Take-offMass of the aircraft. Noise limits can be used to recognize heavier airplanes, whichproduces more noise than lighter airplane. (Chapter 2 Noise Standard containedin Annex 16, Volume I)Althoughnoise levels are lowering with the introduction of new quieter aircrafts withhigher bypass ratio and fuel efficiency, and the retirement of older aircraft,these improvements are being offset by increasing air traffic. Further, noisereduction technologies are used in engine and airframe designs which leads to decreasein airplane noise. This result in further stringency increase of the noisestandard by ICAO (Chapter 4 Noise Standard contained in Annex 16, Volume I). 2.
Land Use Planning and Management:???Land-use planning andmanagement is the second mitigation measure to make sure the activities nearairport are compatible with aviation. The main goal of this measure is tominimize the number of people affected by noise pollution. ICAO has published a manual inAnnex 16, Volume I, Part IV and in the ICAO Doc 9184, Airport Planning Manual,Part 2 – Land Use and Environmental Control. The manual provides guidance onusing of various tools to minimize and control the impact of aircraft noise tohuman life living near the airport. The manual describes examples of someStates who adopted mentioned practices for land-use planning and management.3.
Noise Abatement Operational Procedures:Day-to-day operations alsoimpacts the noise produced by airports. ICAO assists in developing and makingstandards for noise operational procedures that are safe and cost-effective.The procedures include noise preferred runways and standard procedure for atake-off and landing, which produces low noise. 4. Operating Restrictions:?Noise concerns have madesome States to enforce banning the operation of noisy aircraft atnoise-sensitive airports and reduction in flights in certain hours of the day.Examples of actions taken by airport owners around the UnitedStates are given below:· Night Time Operating Restrictions – Lindbergh Field in San Diego,California; Pearl Harbor, Oahu; Washington National 7· Total Jet Ban – Santa Monica Municipal Airport, California;Watertown Municipal Airport, Wisconsin 7· Limit number of night time operations – Minneapolis- St. Paul 7· Noise Preferential Runways – Atlanta, Miami, Tampa, San Juan,Boston-Logan, Hartford-Bradley, O’Hare, Midway, Cleveland Hopkins,Detroit-Wayne County, Minneapolis-St.
Paul, Moisant-New Orleans, Denver,Pittsburgh, LaGuardia, Newark, Los Angeles, San Francisco and others 7The Federal Aviation Administration (FAA) havealso adopted the Aviation Noise Abatement Policy (ANAP) to reduce aircraftnoise at the source – the aircraft itself. FAA has standards and noise limitswhich regulates maximum noise level an aircraft can produce. Aircrafts mustachieve the standards to get airworthiness certification.
FAA provides standards and certification based on aircrafttype. FAA also has a list of estimated noise level in a weighted decibel forcertified and uncertified airplanes published on their website. It alsoprovides list of noise levels for the airplanes currently certified under FARPart 36 and under ICAO Annex 16 standards. These estimated levels can be usedby applicants to demonstrate their aircraft’s compliance with Part 36.National Aeronautics and Space Administration (NASA) is conducting researchthrough a program called Quiet Aircraft Technology program, which aims toreduce aircraft noise pollution. NASA aims to develop the technology to reducecommercial aircraft noise by 10 effective perceived noise dB.
NASA has alsobeen working with the aircraft engine manufacturers to reduce the sound bydesigning engines with larger fan blades. Larger fan blades turn at a slowertip speed, which in turn reduces noise and fuel consumption. NASA AircraftNoise Prediction Program (ANOOP, 1996) was used to assess a module whichimproves fan noise prediction capability with small turbofan engines. As currentaircraft system noise prediction tools ANOOP rely on current knowledge, the abilityof ANOOP to extrapolate unconventional configurations is not accurate. Becauseof this, as a part of Quiet Aircraft Technology Program, a new computationaltool (AVATAR) is under development that will account for engine placement,individual airframe components and non-standard atmospheric conditions (example:gradients, wind) for the propagation of sound from the aircraft to the ground.
Community Groups:There areseveral community organizations all around the world that has taken this issueinto their hands to raise awareness and take actions to reduce effect ofairport noise pollution in their everyday life. Even though India is still inprocess of making standards, there are several organizations who are raisingawareness among the people living in airport vicinity about the effect of noisepollution on their health. One of the such organization in India is Awaaz Foundation, they are actively creating awareness ofadverse health effects from noise. In India, the noise pollutioninformation was collected for the first time by Awaaz foundation, and it waspresented to the Courts, Citizens, Police, State and Union Government. The steptaken against noise pollution by Awaaz foundation motivated Government of Indiato implement rules and regulations. It has now successfully petitioned stateand local government in India to enforce strict noise pollution laws.
Another such organization is AReCO: Alliance of Residents ConcerningO’Hare Inc. This group represents over 1200 residents from 42 communitiesconcerned about O’Hare International Airport, Chicago Illinois. They are activesince 1994 and have done remarkable work in various ways to protect communityfrom noise pollution.
One of their recent remarkable work was helping homeownersto noise proof their homes and apartments by proper funding.