Jan. 1, 2006, is the date for the implementation of the International Civil Aviation Organization’s (ICAO) Chapter 4 noise limits. The latest noise and emissions standards (European terminology uses “Chapter” to correspond with the U.S. term “Stage”) should have no direct immediate effect at all on business aircraft operations, but some ICAO language surrounding the new rules could be indicative of future trends in setting noise and emissions policies worldwide. (See AIN, January, page 1.)
According to ICAO regulations, the new standard will apply only to “newly certified aeroplanes and to Chapter 3 aeroplanes for which re-certification to Chapter 4 is requested.” Furthermore, other regulations, such as those on emissions and the existing Chapter 2 ban, do not include aircraft less than 75,000 pounds, so the majority of older corporate jets and turboprops are not affected.
In the future, however, ICAO may de-emphasize its own rules and push for airports around the world to impose their own limitations. European governments and the European Commission (EC) have already indicated a strong inclination to push ahead with more stringent restrictions on aircraft noise and engine emissions.
No Need to Worry, Yet
According to the strict language of the new rule, operators needn’t worry about ICAO ever banning their Stage/Chapter 3 business aircraft. “ICAO’s Assembly Resolution A33-7 in 2001 clearly stated that no ban on Chapter 3 aircraft can be imposed on the grounds that Chapter 4 applies to new aircraft,” Dominique Gardin, an official with the French civil aviation authority (DGAC) told AIN. Gardin is also a French member of ICAO’s Committee on Aviation Environmental Protection (CAEP).
Moreover, he said, the April 2002 ban on Chapter 2 aircraft in Europe did not apply to aircraft weighing less than 75,000 pounds or seating 19 or fewer passengers.
The French CAEP member now regards a protocol in which unilateral restrictions set by airports serve as a more efficient way to encourage airframers and engine manufacturers to make even quieter aircraft. “The future of noise reduction also lies in operational procedures, such as optimized flight paths around airports,” Gardin added.
Many European airports already have their own noise rules and financial incentives (that is, penalty fees for noisy aircraft). They generally factor a noise-to-weight ratio into their landing-charge formula. At night, however, rules are most often based on noise as an absolute value.
Airports Define Sub-categories
In Europe, a common approach at airports is to base noise rules on margins relative to Chapter 3 standards. For example, France’s Lyon Saint Exupéry Airport defines the “most noisy aircraft within Chapter 3 category” as those within five decibels of Chapter 3 limits. The airport has a curfew on such aircraft from 11 p.m. to 6 a.m. In addition, thrust reversers cannot be used from 10 p.m. to 6 a.m., except for safety reasons.
A similar problem applies with emission regulations. In addition to those for nitrogen oxides (NOx), unburned hydrocarbons (HC) and carbon monoxide (CO), limits exist for emissions of smoke particles. Unfortunately, really small particles of these elements can have a disastrous effect on human lungs, plus they are very difficult to detect. Another challenge for future emission regulation is taking interactions into account. “When you try to reduce fuel burn, you generally increase temperature and pressure; you can therefore create a problem with a higher NOx production,” Gardin explained. The NOx family is the critical pollutant. It is bad for human health, but more important, ozone can form from NOx. In and around big cities, ozone concentration is a major pollution problem.
All new engines certified after Jan. 1, 2008, with thrust of 6,000 pounds or more (typically powering super-midsize business jets such as the Raytheon Hawker Horizon, Bombardier Challenger 300, Dassault Falcon 2000 and the Cessna Citation X), will be required to demonstrate 12-percent lower NOx emissions under the new CAEP standards.
In the late 1990s, a dispute over Stage/ Chapter 3 hush kits brought the EC and the U.S. government into head-long confrontation. In fact, the incident came close to provoking a full-blown transatlantic trade war. The EC attempted to ban the use of hush kits that it deemed to be “marginal” in Chapter 3 noise compliance. To avoid another such dispute, “a sentence was added to Chapter 4, saying recertification should guarantee that it is equivalent to an initial certification,” Gardin explain