To most pilots, the roar of an aircraft engine is music to the ears. Aviation enthusiasts get goose bumps from the unmistakable growl of a Rolls-Royce Merlin in a P–51 Mustang or the nostalgic sound of big radial engines powering a classic bomber. Heck, you can even buy compact discs with your favorite airplane sounds burned into them. Unfortunately, the nonflying public does not share the same enthusiasm when it comes to airplane noise. The general perception is that if you can hear an airplane, it is too close.
Most people perceive aircraft sounds as noise. Studies have pointed out that unpleasant noises are perceived to be louder than more pleasing sounds of the same level. With that in mind, the sound level of an overflying airplane in decibels may well be less than that of the neighborhood children playing in the street. But which do you think will be perceived as noise?
This overall perception of airplanes and noise has fueled an alarming number of airport closures in the past few decades. Today, several California airports are hotbeds of antinoise activity. The problem is certainly not limited to just that state. Florida residents have increasingly lobbied for less aircraft noise at airports in Naples, Boca Raton, and Lantana. What started out as a few neighbors complaining about noise has snowballed into operational restrictions at these airports. Curfews, bans, and other limitations imposed at one airport then start a ripple effect, both nationally and internationally.
Think about it. If an airport in the East has a 10 p.m. curfew, a jet can't leave the West Coast for that airport after about 2 p.m. Going the other direction, a jet must now depart the East no later than 6 p.m. in order to make the 10 p.m. curfew placed on an airport in California. Narrowing the time window in which aircraft can operate squashes more flights into a shorter period of time. Couple this with other issues and it's no wonder we're facing record airline delays. The scary part is that what's a problem for jets today will become a problem for light general aviation airplanes in the near future. More on that later.
What can you do?
In general, GA pilots are apathetic about the noise issue while citizens are quite proactive in efforts to achieve their goal. Worse is the fact that cases won by citizens in one locality can set precedent for others across the country. Pilots are quick to point out "the airport was here first" argument. Although a fact in most cases, it is a moot point as far as the neighboring community is concerned. By the time the noise issue gets to the local government level this argument holds little or no clout. While airport users are beating the-airport-was-here-first argument, the larger and more vocal group of citizens is urging local politicians to place noise-abatement restrictions on the airport. If you're lucky the two sides will agree on voluntary noise restrictions. But if airport users ignore voluntary restrictions, mandatory restrictions may soon be implemented. After that, be prepared for curfews, bans, and eventual airport closure. A once-thriving airport can be reduced to a condo-builder's dream in 10 to 20 years.
The most effective way to battle the noise issue is to start an airport advocacy group. Airport associations and other organizations such as AOPA's Airport Support Network (ASN) band together users of airports to point out ways in which the local airport benefits the community. Remind citizens of the often-unseen benefits that local airports bring: air ambulance, police, and fire services; search and rescue; feeder freight; agricultural and insecticide application; traffic reporting; pipeline patrol; and airlifting of emergency supplies in the event of a natural disaster, such as a flood or earthquake. Local airports also contribute to the economy by attracting businesses to the area. Since many companies have corporate aircraft, a nearby airport makes your county or municipality an attractive place to set up shop. Finally, urge the citizens to understand that responsible airport growth could actually raise property values and make the quality of life in your area better.
GA increasingly taking the spotlight
Technological advances in engine design have made modern jet engines very quiet, while our piston engines — with a few exceptions — are just as noisy as they've been since their inception. It used to be the larger jets with the straight-pipe turbojet engines that caused the noise police to drop their doughnuts and call the airport. Through attrition and bans on Stage 1 and 2 aircraft, however, those older airliners are being replaced with new-generation turbofans that are very quiet. The same is happening at the GA airports. Corporate jets with the blowtorch engines are now being replaced with those powered by high-bypass turbofans that are hardly louder than a high-performance single.
ýn addition, a sensitivity shift has occurred among residents of neighboring communities. A Boeing 707 rattling the windows of a house 30 years ago was loud by anyone's standards. Today, a much quieter Cessna CitationJet whistling off a nearby runway is perceived to be just as noisy by the same people.
Further exacerbating the noise issue is the fact that the FAA is in the process of defining a new aircraft noise certification standard, commonly referred to as Stage 4, as part of the administration's Aviation Noise Abatement Policy of 2000. Stage 4 noise requirements will be more stringent (read quieter) than current Stage 3 requirements. Current certification standards for noise affect all jets, but the FAA's proposed noise policy mentions for the first time a new standard for "large propeller aircraft," although how large these aircraft are has yet to be defined. As history has shown, noise restrictions are trickling down to smaller and smaller aircraft, and it may be only a matter of time before small GA aircraft are targeted.
The unfortunate part is that there are few technological developments under way that will allow propeller-driven aircraft to meet new noise certification standards. In addition, the research and development costs for manufacturers to meet new noise standards will likely be passed on to the customers. Cessna made a step in the right direction when it certified its 172R in 1996. To satisfy European noise requirements, the new Skyhawks utilize a larger Lycoming IO-360 engine limited to 2,400 rpm rather than using the design's previous O-320 engine that turned at 2,700 rpm. While carrying around a larger engine that is derated may not be the best way to reduce noise, it was the most economical way for Cessna to meet noise requirements with available technology.
Since the Stage 4 noise proposal is in its adolescence, predicting how GA aircraft will be affected by the new requirements would only be a guess at this point.
The future?
If no actions are taken, what will noise issues do to GA in the United States? Take a look overseas. In Europe the problem has led to Draconian restrictions on when, where, and how GA airplanes can fly. Expect to see performance-robbing mufflers stretched out along the belly of airplanes in an attempt to meet increasingly strict noise regulations. And because research and development costs far outweigh the profit to be made, there are few new-technology powerplants on the drawing board to replace the old-fashioned piston engines in use today.
In the future, local traffic patterns will be designed to mitigate noise with no regard to standardization or the ability to safely reach the runway in the event of power loss. Three- and four-blade propellers will likely become mandatory in an attempt to reduce propeller tip speeds, and therefore noise, with little or no regard to aircraft performance. GA pilots will have to plan flights around airport curfews and noise regulations rather than around their own schedules and the weather.
AOPA and other proaviation organizations are working now to stop what's happened overseas from occurring here in the states. But despite the best efforts put forth by GA's alphabet organizations, this uphill battle must be fought on the front lines by the users of the system, the pilots.
Techniques to minimize your noise footprint
The most obvious way pilots can win the noise battle and perhaps save their troubled airport is to reduce their noise footprint, a term used to describe the path of airplane's noise . Pilots have to fly responsibly and realize the consequences of their actions. For example, making 10 circles over your house at 500 feet agl only proves that your freedom is now intruding on the lives of all your neighbors. It should also be the responsibility of all flight instructors to remind their students to be aware of the noise that aircraft create. The following are some techniques to keep in mind:
Keep propeller rpm to a minimum. Most of the noise from a typical GA airplane comes from the propeller, the tips of which at maximum rpm can approach the speed of sound. Keeping the propeller rpm of a constant-speed prop lower drastically reduces the amount of noise your airplane generates. Reduce propeller rpm as soon as practical after takeoff. Most normally aspirated Lycoming and Continental engines permit "oversquare" operation despite the old wives' tale that manifold pressure should never exceed the rpm in hundreds. With this in mind, leaving the throttle full and decreasing rpm by 200 reduces power only slightly — but greatly reduces the noise output.
When arriving at an airport, do not advance the propeller control to high rpm until the propeller falls out of governing range. There are few sounds more annoying than those that come from a pilot who advances the propeller control fully forward while on a downwind leg in the pattern. In a high-powered single like a Beech Bonanza or Cessna 210, this makes an ear-piercing racket that can be heard from miles away. In addition, the rapid change in sound may lead the uneducated to think that something is wrong with the airplane.
Climb at the best-angle-of-climb airspeed. For airplanes equipped with fixed-pitch propellers, the only practical method of reducing the noise of the airplane is to place the maximum amount of distance between the airplane and those on the ground. Climbing at the best-angle-of-climb speed (VX) helps place hundreds of feet of altitude between your airplane and the neighbors. Of course, pilots of airplanes equipped with constant-speed props should also use this technique in conjunction with reducing rpm. Pilots of twin-engine airplanes should climb at the best-single-engine-rate-of-climb speed (VYSE) for the best combination of climb rate and safety. An in-house study at AOPA showed that the association's Beech A36 Bonanza was more than five decibels quieter over the departure end of the runway if the rpm was reduced to 2,500 and the airplane climbed at VX, compared to a flatter climb at the maximum 2,700-rpm setting. Pilots are also encouraged to avoid intersection takeoffs, which place the airplane at a lower altitude when crossing the airport fence.
Avoid low, dragged-in approaches and wide traffic patterns. Except in special circumstances, flying a traffic pattern at a lower than normal altitude is unnecessary, especially when the airplane is configured with gear and flaps down early in the pattern. It takes cruise power or higher to maintain altitude with ýll of that drag hanging in the breeze. Besides, other pilots are looking for traffic at the same altitude in the pattern, not 300 feet below it. In general, keep the pattern tight, and don't leave the traffic pattern altitude until abeam the threshold or when turning your base leg.
Familiarize yourself with the airports that you visit and where possible, follow voluntary noise-abatement procedures. An airport that has voluntary noise-abatement procedures has already endured a noise battle with its local community. Not following the voluntary procedures gives still more ammunition to the citizens at the next town meeting. Know the traffic pattern design and altitude for the airport prior to your arrival. Many airports utilize nonstandard traffic patterns in an attempt to reduce noise complaints. Right-hand patterns or those that take the airplane over industrial areas rather than housing developments are becoming more common. At some local airports, the unicom operator usually reminds inbound aircraft of special procedures — for example, flying their downwind leg 1.5 miles south of the airport at a higher than standard altitude in order to appease the local citizens. Unfortunately, when pilots ignore this reminder on a daily basis, the airport manager gets the phone calls.
CFIs must be proactive in teaching friendly flying techniques. Flight instructors are the front line of defense in the noise battle. Urging your students to comply with the above techniques will help ensure your airport's survival and possibly the security of your job. In addition, CFIs should take students to airports in more rural areas to perform touch and goes. When teaching turns on or about a point it would be prudent to not always use the same reference point and to try to avoid populated areas.
Pilots need to be salesmen to the public when it comes to aviation. Ignorance is aviation's worst enemy. Land use policies are often ill-conceived, and pilots should be quick to point out to the community that housing developments planned for construction near the airport are irresponsible. When faced with such situations, pilots should offer to take city officials or members of the media for a ride so that they can see and experience the consequences of such plans.
Noise is the number-one reason for airport restrictions, operational limitations, or outright closure. In addition, local governments often deny approvals for airport safety improvements such as longer runways and instrument approaches because they are persuaded by the local residents' fear that larger, noisier aircraft will destroy their peace and quiet. With this in mind, pilots have to realize that we are treading on thin ice.
The fact that piston aircraft powerplants are as noisy as ever while jets are getting quieter reinforces the fact that noise problems are going to become an ever-increasing clamp on where, when, and how we can fly. In order for the aviators of tomorrow to enjoy this passion, we must make efforts to get along with the local community. We must also realize that noise is an issue that affects aviation across the entire country, not just in the local community. Out of earshot, out of mind is the name of the game when it comes to avoiding a call from the noise police.
Peter A. Bedell, AOPA 1136339, is a captain for a regional airline and former technical editor of AOPA Pilot.
Efforts to preserve your local airport
So what's AOPA doing to help mitigate noise problems and possible airport closures throughout the United States? To date, several efforts by the association have assisted in keeping your runways from being rolled up. Flying Friendly , an AOPA-produced video, was distributed to hundreds of airport managers and FBOs throughout the country. The video demonstrates how airport managers can more effectively defend the airport from antiairport movements. Flying Friendly also demonstrates pilot techniques that will help to minimize an airplane's noise footprint. Check out the video at your airport's management office or FBO.
For years AOPA's Airport Directory and AOPA's Airport Directory Onlineýhave noted airports with right-hand traffic patterns and nonstandard traffic pattern altitudes to help prevent potential conflicts with voluntary or mandatory airport noise restrictions. Following these guidelines will help to ensure that your arrival or departure from a noise-sensitive airport will not set back relations with the local community.
By far, AOPA's largest effort to assist local airports is its Airport Support Network (ASN). Volunteers from across the nation offer to be the eyes and ears of the association in matters that affect their local airports. When there's an effort that affects the operation of your local airport for any reason, AOPA, through the ASN volunteers, will be able to react to early warning flags. Now AOPA can act on threats to airports early in the negotiation process, when there is still hope. In the past, AOPA was alerted to a local issue in the eleventh hour of negotiations when little or nothing could be done. In many cases ASN volunteers are affiliated with — or help to start — a local airport association or pilots' group; local proairport support is often critical to a positive outcome.
ASN is in its fourth year and proving to be very successful in stopping issues before they become threatening to the airport's livelihood. A recent example was ASN volunteer Gary Parsons, who spearheaded a local pilot movement against repeated proposals to close the Hawthorne Municipal Airport, east of Los Angeles. His efforts pointed out the airport's attraction to, among other things, nearby industry. Through his efforts, the proposal to turn the land into a shopping mall was thwarted.
The goal of the program is to have an ASN volunteer at every public-use airport in the country. So far 915 ASN volunteers have signed up. For more information about ASN, visit the Web site ( www.aopa.org/asn/). — PAB
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