Tupolev 154M noise asesment

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• Tupolev 154M noise asesment

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The FAA issued FAR-36 (which establishes the limits on take-off, approach, and sideline noise for individual aircraft), followed by ICAO issuing its Annex 16 Part 2, and JAA issuing JAR-36. These rules have since been revised several times, reflecting both improvements in technology and continuing pressure to reduce noise. As of this writing, the rules are enunciated as three progressive stages of noise certification. The noise limits are stated in terms of measurements at three measuring stations, as shown in Fig. 5.1: under the approach path 2000 m before touchdown, under the take-off path 6500 m from the start of the take-off roll, and at the point of maximum noise along the sides of the runway at a distance of 450 m.

Figure 5.1 Schematic of airport runway showing approach, take-off, and

sideline noise measurement stations.

The noise of any given aircraft at the approach and take-off stations depends both on the engines and on the aircraft’s performance, operational procedures, and loading, since the power settings and the altitude of the aircraft may vary.

The sideline station is more representative of the intrinsic take-off noise characteristics of the engine, since the engine is at full throttle and the station is nearly at a fixed distance from the aircraft. The actual distance depends on the altitude the aircraft has attained when it produced maximum noise along the designated measuring line. Since FAR-36 and international rules set by the International Civil Aviation Organization (ICAO annex 16, Part 2) which are generally consistent with it have been in force, airport noise has been a major design criterion for civil aircraft.

Stricter noise pollution standards for commercial aircraft, established by the International Civil Aviation Organization, came into effect worldwide on 1 April. Most industrialized countries, including all EU states, enforced the new rules and the vast majority of airliners flying in those states already meet the more stringent requirements. But some Eastern European countries are facing a problem, especially Russia. Eighty percent of its civilian aircraft fall short of the standards, meaning it will not be able to apply the new rules for domestic flights. Even more worrisome for Moscow is the fact that Russia could find many of its planes banned from foreign skies. Enforcement of the new rules could force Russia to cancel 11,000 flights in 2002, representing some 12 percent of the country's passenger traffic.

The new rules have been applied only to subsonic transports, because no new supersonic commercial aircraft have been developed since its promulgation.

5.1 Noise Limits

As mentioned above, all turbofan-powered transport aircraft must comply at certification with EPNL limits for the three measuring stations as shown in Fig. 5.1. The limits depend on the gross weight of the aircraft at take-off and number of engines, as shown in Fig. 5.2. The rule is the same for all engine numbers on approach and on the sideline because the distance from the aircraft to the measuring point is fixed on approach by the angle of the approach path (normally 3 deg) and on the sideline by the distance of the measuring station from the runway centerline.

Figure 5.2 Noise limits imposed by ICAO Annex 16 for certification of aircraft.

On take-off, however, aircraft with fewer engines climb out faster, so they are higher above the measuring point. Here the “reasonable and economically practicable” principle comes into dictate that three-engine and two-engine aircraft have lower noise levels at the take-off noise station than four-engine aircraft.

There is some flexibility in the rule, in that the noise levels can be exceeded by up to 2 EPNdB at any station provided the sum of the exceedances is not over 3 ENPdB and that the exceedances are completely offset by reductions at other measuring stations.

6 Noise Level Calculations

Tupolev 154M Description

For most airlines in the CIS, the Tupolev Tu-154 is nowadays the workhorse on domestic and international routes.

Figure 6.1 Tupolev 154M main look

It was produced in two main vesions: The earlier production models have been designated Tupolev -154, Tupolev -154A, Tupolev -154B, Tupolev -154B-1 and Tupolev -154B-2, while the later version has been called Tupolev -154M. Overall, close to 1'000 Tupolev -154s were built up to day, of which a large portion is still operated.

Table 6.1 Tupolev 154M main characteristics

Реферат опубликован: 28/08/2007