Dear leocarin,
The
FAA classifies aircraft into three stages for clarification:
Stage 1, 2, and 3 in order from loudest to the least noisiest.
Noise levels for Stage definition of aircraft are measured at three points. These points are designed to measure noise levels for
take-off, approach, and flyovers (sideline). Furthermore, classification is also based on the number of engines.
Stage 1A Stage 1 noise level means a take-off, flyover, or approach noise level greater than the Stage 2 noise limits.
Stage 2Stage 2 noise limits for airplanes regardless of the number of engines are as follows:
• For Take-off: 108 EPNdB for maximum weights of 600,000 pounds or more, reduced by 5 EPNdB per halving of the 600,000 pounds maximum weight down to 93 EPNdB for maximum weights of 75,000 pounds and less.
• For Sideline and Approach: 108 EPNdB for maximum weights of 600,000 pounds or more, reduced by 2 EPNdB per halving of the 600,000 pounds maximum weight down to 102 EPNdB for maximum weights of 75,000 pounds or less.
Stage 3Stage 3 noise limits are as follows:
• For Take-off: airplanes with more than 3 engines 106 EPNdB for maximum weights of 850,000 pounds or more, reduced by 4 EPNdB per halving of the 850,000 pounds maximum weight down to 89 EPNdB for maximum weights of 44,673 pounds or less.
• For Take-off: airplanes with 3 engines 104 EPNdB for maximum weights of 850,000 pounds or more, reduced by 4 EPNdB per halving of the 850,000 pounds maximum weight down to 89 EPNdB for maximum weights of 63,177 pounds or less.
• For Take-off: airplanes with fewer than 3 engines 101 EPNdB for maximum weights of 850,000 pounds or more, reduced by 4 EPNdB per halving of the 850,000 pounds maximum weight down to 89 EPNdB for maximum weights of 106,250 pounds or less.
• For Sideline: regardless of the number of engines 103 EPNdB for maximum weights of 882,000 pounds or more, reduced by 2.56 EPNdB per halving of the 882,000 pounds maximum weight down to 94 EPNdB for maximum weights of 77,200 pounds or less.
• For Approach: regardless of the number of engines 105 EPNdB for maximum weights of 617,300 pounds or more, reduced by 2.33 EPNdB per halving of the 617,300 pounds maximum weight down to 98 EPNdB for maximum weights of 77,200 pounds or less.
For The FedEx
Stage 3 Kit configuration click on:
http://www.fedex.com/us/hushkit/configuration/International Civil Aviation Organization (ICAO) distinguishes between three different categories of aircraft based on noise pollution:
Stage 1 aircraft, Stage 2 aircraft, and Stage 3 aircraft.
Stage 1 aircraft, the loudest and most polluting aircraft category. These aircraft are no longer in use.
The main aircraft in use worldwide today is the
Stage 2 aircraft fitted with an aircraft silencing apparatus known as a hushkit. When a hushkit is installed on a Stage 2 aircraft and it meets
Stage 3 noise requirements, the aircraft is generally considered to be Stage 3 aircraft, and it is implied that it would be viewed by everyone as a Stage 3 aircraft.
The FAA is proposing a new noise standard for subsonic jet airplanes and subsonic transport category large airplanes. This noise standard would ensure that the latest available noise reduction technology is incorporated into new aircraft designs.
This noise standard, Stage 4, would apply to any person* submitting an application for a new airplane type design on and after January 1, 2006**.
The first noise certification standards came in 1969, establishing Stage 2 standards for new airplane types. This was followed successively by setting Stage 3 standards in 1977 and the phase-out of Stage 1
airplanes in 1985.
Recognizing that the Airport Noise and Capacity Act of 1990 (ANCA) will require that all civil subsonic turbojet airplanes over 75,000 pounds operating to or from airports in the contiguous United States be Stage 3 compliant by December 31, 1999, representative aircraft selected for this effort are limited to those capable of meeting Stage 3 requirements.
Much of the background for the development of a
Stage 4 noise standard has taken place in the international arena and the work of International Civil Aviation Organization (ICAO).
The text of
Annex 16 describing the maximum noise levels for the
new Chapter 4 noise limit is as follows:
• The maximum permitted noise levels are defined in Chapter 3 of Annex 16; and may not be exceeded at any of the measurement points;
and
• The sum of the differences at all three measurement points between the maximum noise levels and the maximum permitted noise levels (the Stage 4 limit) specified in Chapter 3 of Annex 16 may not be less than 10 EPNdB; and
• The sum of the differences at any two measurement points between the maximum noise levels and the corresponding maximum permitted noise levels specified in Chapter 3 of Annex 16 may not be less than 2 EPNdB.
(1) None of an airplane's maximum noise levels (flyover, lateral, and approach) may be greater than the maximum permitted noise levels for Chapter 3 airplanes, as defined in Annex 16; and
(2) To determine Stage 4 compliance, an airplane's maximum flyover, lateral and approach noise levels are each subtracted from the maximum permitted noise levels. The differences obtained are the noise limit margins, to be used as follows:
(a) When the three margins are added together, the total must be 10 EPNdB or greater; and
(b) When any two of the margins are added together, the sum must be 2 EPNdB or greater.
The working group considered several new, more stringent noise certification options for analysis. They include a "traditional'' option with specified reductions at each noise certification measurement point flyover, lateral, and approach), and three "cumulative'' options that combine the three traditional measurement points allowing a total cumulative reduction without specifying reductions at any one measurement point. The three cumulative options were 8, 11, and 14 decibel reductions from Chapter 3/Stage 3 levels respectively.
The FAA established the Stage 3 noise standard in 1975, but it was not until the end of 1999 that the contiguous United States had an all Stage 3 fleet in operation. Stage 2 airplanes were last produced in 1988, but their operation was permitted for another 12 years. From the time the Stage 3 noise standard was adopted in 1975 until the contiguous United States had an all Stage 3 operational fleet, approximately 25 years had elapsed.
The FAA has no current plan to begin a phaseout of Stage 3 airplanes.
....
*FAA distinguishes between person and other entities, and of course the army is not a person.
Best regards,
Möhlin
