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Aircraft Noise

• Methodology Adopted for Assessing Aircraft Noise Impact
• Results of Noise Impact Assessment
• Aircraft Noise Monitoring
• Aircraft Noise Mitigating Measures
• Aircraft Noise Complaint

Methodology Adopted for Assessing Aircraft Noise Impact

1. Throughout the airport master planning process on the Hong Kong International Airport (HKIA), the Airport Authority in conjunction with the government have conducted assessments to determine the effects of aircraft noise impacts on off-airport areas.

2. The noise impact arising from aircraft operation can be represented by the Noise Exposure Forecast (NEF) contours, a criterion which takes into account the duration of flyover, the peak noise level, the tonal characteristics and the number of aircraft movements in both the daytime and night-time period. The noise impact assessment was conducted in accordance with the guidelines set out by the International Civil Aviation Organization (ICAO) and the Federal Aviation Administration (FAA) of the United States Department of Transport. The FAA's state-of-the-art modelling tools for assessing airport noise exposure were used to generate these noise contours. For the HKIA at Chek Lap Kok, the Hong Kong Planning Standards and Guidelines stipulate a more stringent criterion of NEF 25 contour (as against NEF 30 for Kai Tak Airport) for planning of noise sensitive land uses. This criterion is in line with the international standards adopted by many developed countries.

Results of Aircraft Noise Impact Assessment

3. According to the New Airport Master Plan – Environmental Impact Assessment (NAMP-EIA) completed by the Airport Authority in 1991, its Supplement in 1992 and its Update completed in 1998, only a very small number of residents in North Lantau, predominantly in Sha Lo Wan, are within the coverage of the NEF 25 contour of the HKIA at design capacity and regarded as subject to aircraft noise beyond acceptable level from a planning and land use point of view.

4. Since the opening of HKIA at Chek Lap Kok, several briefings on aircraft noise and flight paths have been given to the concerned District Councils including Kwai Tsing, Sha Tin, Tsuen Wan, Central & Western, Kowloon City, Southern, Yau Tsim Mong, Wan Chai, Eastern, North, Islands, Tuen Mun and Sai Kung.

Aircraft Noise Monitoring

5. The CAD monitors the noise caused by aircraft operations through a computerised Aircraft Noise and Flight Track Monitoring System (ANFTMS). The ANFTMS is comprised of multiple outdoor noise monitoring terminals (NMTs) which are located along or close to the flight paths operating into and out of the HKIA to collect noise data, and a computer system which correlates noise data collected with the actual aircraft flight tracks detected by the CAD's radar system. In view of the commencement of operation familiarisation of the North Runway from 8 July 2022, the CAD has expanded the ANFTMS through the installation of additional NMTs at locations close to the flight paths of the North Runway. At present, the NMTs are located respectively at Sha Lo Wan, Tung Chung, Sunny Bay, Ma Wan, Tsing Yi (2 terminals), Tai Lam Chung, Tsing Lung Tau, Ting Kau, Tsuen Wan, Kwai Chung, Tai Wai, Mid-Levels, North Point, Jardine's Lookout, Shau Kei Wan, Tuen Mun and Siu Lam.

6. The measured noise levels are summarised in the table below:-

Table 1

Measured Noise Levels at Various Districts
(1 January 2023 - 31 December 2023)

Supplementary Information:
1.	Lmax is the peak instantaneous noise level of a noise event.
2.	The noise level experienced at various district is subject to the arrival/departure routes used and therefore varies.
3.	Statistics are based on data recorded by the Aircraft Noise and Flight Track Monitoring System.
4.	The above percentages are with reference to the total movements of aircraft during the period concerned.
5.	Portable NMTs in Tuen Mun and Siu Lam have been put into operation since July 2022.

Aircraft Noise Mitigating Measures

7. The government is conscious of any possible noise impact that aircraft operations may have on local communities and has implemented a number of aircraft noise mitigating measures based on the guidelines of the ICAO, aiming at mitigating noise impact caused by the aircraft without compromising aviation safety. Briefly, these are:-

a) subject to acceptable wind conditions and safety considerations, arrival aircraft between 11 p.m. and 7 a.m. on the following day are normally instructed to land from the southwest over the water. This measure aims to reduce the number of aircraft overflying populated areas such as Tseung Kwan O, Sai Kung, Ma On Shan, Sha Tin, Kwai Chung, Tsing Yi, Tsuen Wan and Tuen Mun (Siu Lam / Tai Lam Chung) during the overnight period;

b) subject to acceptable operational and safety consideration, aircraft departing to the northeast of the airport between 11 p.m. and 7 a.m. on the following day are required to use the southbound route via the West Lamma Channel. This measure aims at reducing the number of aircraft overflying populated areas such as the Kowloon Peninsula and Hong Kong Island;

c) aircraft departing to the northeast of the HKIA are required to adopt the noise abatement take-off procedures laid down by ICAO so as to reduce the noise impact on areas located in the vicinity of the HKIA. Under these procedures, aircraft are required to reduce their power upon reaching an altitude of 800 feet or above to abate aircraft noise;

d) all aircraft approaching the HKIA from the northeast between 11 p.m. to 7 a.m. on the following day are encouraged to adopt the Continuous Descent Approach (CDA), subject to weather and operational considerations. As aircraft on CDA fly higher altitudes, noise experienced in areas such as Tseung Kwan O, Sai Kung and Ma On Shan is expected to be lowered;

e) to reduce aircraft noise at source, subsonic jet aircraft that do not comply with the noise standards stipulated in Chapter 3 of Annex 16 Volume I, Part II to the Convention on International Civil Aviation ("Chapter 3 noise standards") are prohibited from landing or taking off in the HKIA;

f) to strengthen the above measure e), starting from 2014, airlines are not allowed to schedule aircraft which are only marginally compliant with the Chapter 3 noise standards to land and take off in HKIA;

g) to further alleviate the aircraft noise impact on the local communities, commencing from March 2019, airlines are not allowed to schedule aircraft that do not comply with the more stringent noise standards stipulated in Chapter 4 of Annex 16 Volume I, Part II to the Convention on International Civil Aviation or equivalent to land and take off in HKIA between 10 p.m. and 7 a.m. on the following day; and

h) all aircraft equipped with satellite-based navigation technology departing to the northeast of the HKIA between 11 p.m. and 7 a.m. on the following day are encouraged to adopt a set of Radius-to-Fix ("RF") flight procedures. Aircraft flying RF procedures adhere closely to the nominal centre line of the flight track when making south turn to the West Lamma Channel. This keeps the aircraft at a distance away from the areas in the vicinity of the flight paths, and reduces the impact of aircraft noise on people in these areas.

8. As regards the measures mentioned in paragraph 7(a) and (b) above, Tables 2 and 3 below show the achievement figures. The results indicate that high percentages of achievement have been attained during the periods with the implementation of the measures. These measures could not be applied only on a small number of occasions due to various operational reasons including prevailing wind conditions, maintenance of navigation aids prior to flight calibration, or air traffic conflicts.

Table 2

Achievement record for aircraft arriving
between midnight and 7 a.m. on the following day to land from the southwest
when wind conditions and traffic situation permit*

Year	Total number of aircraft arriving between 00:00 and 07:00 hours*	Total number of aircraft landed from the southwest during the same period	Achievement Rate (%)
1998 (Oct-Dec)	1,066	1,037	97.3%
1999	4,720	4,293	91.0%
2000	5,695	5,248	92.2%
2001	5,526	5,201	94.1%
2002	7,065	6,660	94.3%
2003	6,838	6,409	93.7%
2004	8,641	7,958	92.1%
2005	10,865	9,437	86.9%
2006	12,622	11,126	88.1%
2007	14,002	11,950	85.3%
2008	14,869	13,263	89.2%
2009	13,266	12,201	92.0%
2010	17,126	14,704	85.9%
2011	19,713	17,174	87.1%
2012	21,099	18,006	85.3%
2013	24,111	21,434	88.9%
2014	27,655	23,601	85.3%
2015	30,039	23,548	78.4%
2016	29,333	24,538	83.7%
2017	29,509	25,670	87.0%
2018	29,364	24,904	84.8%
2019	32,018	25,874	80.8%
2020	19,867	16,422	82.7%
2021	20,524	16,859	82.1%
2022	18,197	15,980	87.8%
2023	28,464	24,772	87.0%

Year 2023

Month	Total number of aircraft arriving between 00:00 and 07:00 hours*	Total number of aircraft landed from the southwest during the same period	Achievement Rate (%)
January	1,659	1,604	96.7%
February	1,727	1,696	98.2%
March	1,975	1,838	93.1%
April	1,992	1,860	93.4%
May	2,295	1,798	78.3%
June	2,484	1,835	73.9%
July	2,462	1,691	68.7%
August	2,512	1,408	56.1%
September	2,519	2,318	92.0%
October	2,705	2,593	95.9%
November	2,917	2,917	100.0%
December	3,217	3,214	99.9%

Note 1:	(*)Starting from 16 May 2023, the implementation time period has been changed to 11 p.m. until 7 a.m. on the following day.
Note 2:	Statistics are based on data recorded by the Aircraft Noise and Flight Track Monitoring System.

Table 3

Achievement record for aircraft departing
to the northeast of the airport
between 11 p.m. and 7 a.m. on the following day (Note 1)
to use the southbound route via the West Lamma Channel

Year	Total number of aircraft departing on Runway 07 between 23:00 and 07:00 hours*	Total number of departing aircraft using the southbound route during the same period	Achievement Rate (%)
1998 (Oct-Dec)	802	794	99.0%
1999	5,913	5,871	99.3%
2000	9,737	9,686	99.5%
2001	10,790	10,634	98.6%
2002	11,416	11,365	99.6%
2003	11,382	11,340	99.6%
2004	14,104	13,989	99.2%
2005	16,115	15,941	98.9%
2006	18,533	18,340	99.0%
2007	19,596	19,449	99.2%
2008	21,492	21,239	98.8%
2009	21,162	21,034	99.4%
2010	23,195	22,860	98.6%
2011	25,389	25,170	99.1%
2012	26,705	26,605	99.6%
2013	30,035	29,777	99.1%
2014	28,761	28,385	98.7%
2015	27,221	26,895	98.8%
2016	28,688	28,289	98.6%
2017	31,136	30,624	98.4%
2018	30,875	29,921	96.9%
2019	29,354	28,643	97.6%
2020	17,410	17,244	99.0%
2021	15,819	15,667	99.0%
2022	15,002	14,863	99.1%
2023	22,745	22,386	98.4%

Year 2023

Month	Total number of aircraft departing on Runway 07 between 23:00 and 07:00 hours*	Total number of departing aircraft using the southbound route during the same period	Achievement Rate (%)
January	1,790	1,787	99.8%
February	1,784	1,784	100.0%
March	2,007	1,997	99.5%
April	1,974	1,922	97.4%
May	1,697	1,694	99.8%
June	1,585	1,524	96.2%
July	1,595	1,546	96.9%
August	1,286	1,263	98.2%
September	2,022	1,938	95.8%
October	2,086	2,035	97.6%
November	2,372	2,359	99.5%
December	2,547	2,537	99.6%

Note 1:	(*)Prior to 7 January 1999, the implementation time period was between midnight and 7 a.m..
Note 2:	Statistics are based on data recorded by the Aircraft Noise and Flight Track Monitoring System.

Aircraft Noise Complaint

9.	Complaint Hotline:	2769 6969
	Email:	aircraftnoise@cad.gov.hk
	Fax:	2326 3654
	Aircraft Noise Complaint Office
	Civil Aviation Department Headquarters
	1 Tung Fai Road, Hong Kong International Airport
	Lantau, Hong Kong