Executive summary. This report covers January to September 2017.

Transcription

1 LHR Airspace & Noise Performance Q3 Report 217

2 Contents Executive Summary 3 KPI 4 1ft requirements/infringements 5 Departure Noise Limits 7 Day Noise/Night Noise Infringements 8 Track Keeping 9 CDA 14 Joining Point 16 Go Arounds 2 Night noise/qc Usage 21 Arrival and Departure information 25 Engine Ground Running 26 Glossary of Terms 28 Page 2 Heathrow Airport Airspace & Noise Performance Q3 Report 217

3 Executive summary This report covers January to September 217. January to September 217 saw the airport operating at 17.38% easterly and 82.62% westerly operations. After the first two quarters showing worse performance, it s good to be able to report that the number of 1ft infringements is now lower than the corresponding period last year. We will continue to work with airlines on this metric. Overall noise infringements for the Night Period are down in the reporting period. Of the nineteen infringements recorded in the reporting period, fourteen have been in the Night Period and five have been recorded during the day. These numbers compares favourably with the overall number for the same period last year when there were 29 infringements after 23 and 2 day time infringements. Track keeping on all runways has seen a jump of.8% compared to 216 and now sits at 95.87% compliance. We continue to talk to airlines and share data on this key metric with the aim to further improve track keeping. For this quarter the minimum climb gradient performance is 99.7% of all departing aircraft met the minimum climb gradient. We continue to work with airlines about this metric. The 24hr CDA figures shows a healthy level of improvement in the level of compliance and we continue to engage with airlines, with the aim of driving up performance. Following work by our Airside Safety colleagues, reporting of Engine Ground running has undergone a thorough review this year, and new reporting measures have been put in place. A direct comparison looking back is no longer possible and it s the latest set of figures that we will use as a baseline as we move forwards. All charts and graphs are shown on the pages that follow are for reference purposes only. Heathrow Airport Airspace & Noise Performance Q3 Report 217 Page 3

4 KPI chart to end of September 217 KPI Comparable 216 data 217 Comparison RAG January to September 216 January to September 217 1ft GREEN Noise Infringements Night GREEN Noise Infringements Day 2 5 GREEN Track Keeping Average 27R 97.22% 97.82% GREEN Track Keeping Average 27L 96.83% 97.51% GREEN Track Keeping Average 9R 89.21% 9.21% GREEN Track Keeping Average 9L*** 8.36% 86.% GREEN Track Keeping All Runways 95.7% 95.87% GREEN Minimum Climb Gradient Reporting 99.7% CCO Compliance All Runways 56.% 54.1% GREEN CDA Day Average 87.45% 87.93% GREEN CDA Night Average 92.67% 92.44% GREEN CDA Core Night Average 95.77% 96.33% GREEN CDA 6: Hour Average 91.76% 91.22% GREEN 24 Hour CDA Average* 88.3% 88.34% GREEN Monthly Night Runway Alternation 99.8% 1.% GREEN Joining Point Day LATES Average.32%.31% GREEN Joining Point Day LOWS Average 13.6% 17.36% RED Joining Point Night LATES Average* 1.87% 1.6% GREEN Joining Point Night LOWS Average* 5.34% 4.26% GREEN Night Quota Pro Rata for Quota Count** 44.9% 46.9% Night Quota Pro Rata for Movements** 9.8% 9.5% * Service levels in NATS contract ** Excess usage pro-rata indicates increased risk of aircraft being refused permission to arrive or depart during 23:3-6:hrs local *** Low numbers of departures off 9L due to the Cranford agreement can result in a wide fluctuation in performance when compared to the other three runways. RAG Green: Better than previous score or within 4.99%. Amber: Worse than previous score, but within %. Red; Worse than the previous score, by 1% or greater Each element of this report is preceded where applicable by the relevant Aeronautical Information Publication (AIP) reference and summary text detailing the purpose of the requirement. Data is then presented on current performance. It should be noted that Heathrow is 83ft above sea level and the ANOMS NTK system measures height relative to Heathrow elevation and not sea level. References in the AIP are usually above sea level (quoted as Heathrow QNH) and therefore need to be reduced by 83ft to be comparable with heights as measured by ANOMS. No account is taken of the variability of heights as measured by the radar which, depending on the distance from the radar head can be +/- 2ft from that indicated. This is obviously allowed for by NATS when managing operations. FOR THE PURPOSES OF THIS REPORT ANY REFERENCE TO HEIGHT SHOULD BE READ AS ABOVE AIRFIELD ELEVATION UNLESS OTHERWISE STATED. ALL DATA CONTAINED WITHIN THIS REPORT SHOULD BE CONSIDERED IN LIGHT OF THE PRECEDING TEXT AND COMMENT BOX THAT FOLLOWS. Page 4 Heathrow Airport Airspace & Noise Performance Q3 Report 217

5 1ft requirement AD 2-EGLL (Page 24) After take-off the aircraft shall be operated in such a way that it is at a height of not less than 1 ft aal at 6.5km from start of roll as measured along the departure track of that aircraft. Period From 1/1/217 to 3/9/217 Height Infringement Reports 1ft Infringements by Month with Temperature No of Aircraft failing to reach 1ft at 6.5 km Jan 16 Feb 16 No of Aircraft failing to reach 1ft at 6.5km against Temp Mar 16 Apr 16 May 16 Jun 16 Jul 16 Aug 16 Sep Average Monthly Temperature Month <1ft Average Temp <9ft Heathrow Airport Airspace & Noise Performance Q3 Report 217 Page 5

6 1ft infringements by airline London Heathrow Period From 1/1/217 to 3/9/217 Airline < 1 ft < 9 ft ABW AIRBRIDGE CARGO AIRLINES 1 1 ALK SRI LANKAN AIRLINES 1 AVA AVIANCA 1 BAW BRITISH AIRWAYS ETD ETIHAD AIRWAYS 2 1 KAL KOREAN AIR 1 LOT LOT POLISH AIRLINES 1 MAS MALAYSIA AIRLINES MAU AIR MAURITIUS PAL PHILIPPINE AIRLINES INC 8 PIA PIA 1 QFA QANTAS 1 QTR QATAR AIRWAYS 4 SAA SOUTH AFRICAN AIRWAYS 11 7 SIA SINGAPORE AIRLINES 18 2 SIG UNKNOWN 1 TAP TAP PORTUGAL 1 THA THAI AIRWAYS INTERNATIONAL 4 4 UAE EMIRATES 2 UAL UNITED AIRLINES 3 VIR VIRGIN ATLANTIC 37 4 Total of all Infringements: 466 Page 6 Heathrow Airport Airspace & Noise Performance Q3 Report 217

7 Departure Noise Limits AD 2-EGLL (Page 25) Subject to sub-paragraphs (5) and (6) below, any aircraft shall, after take-off, be operated in such a way that it will not cause more than 94 dba Lmax by day (from 7 hours to 23 hours local time) as measured by any noise monitoring terminal at any of the sites referred to in subparagraph (2*) above. Subject to sub-paragraphs (5) and (6) below, any aircraft shall, after take-off, be operated in such a way that it will not cause more than 89 dba Lmax by night (from 23 hours to 7 hours local time) and, that it will not cause more than 87 dba Lmax during the night quota period (from 233 to 6 house local time) as measured by any noise monitoring terminal at any of the sites referred to in subparagraph (2*) above. (5) The limits specified in sub-paragraphs (3*) and (4*) above shall be adjusted in accordance with the following table in respect of any noise monitoring terminal at any of the sites referred to in the table in sub-paragraph (2*) to take into account of the location of that terminal and it s ground elevation relative to the aerodrome elevation. (6) For the purposes of determining an infringement of the limits specified in sub paragraphs (3*) and (4*) above, if the aircraft was requested to take-off with a tailwind, an amount of up to 2dB of the noise recorded at the noise monitor should be disregarded. The amount to be disregarded shall be:.4 db for a tailwind of up to 1 knot..8 db for a tailwind exceeding 1 knot but not exceeding 2 knots 1.2 db for a tailwind exceeding 2 knots but not exceeding 3 knots 1.6 db for a tailwind exceeding 3 knots but not exceeding 4 knots 2. db for a tailwind exceeding 4 knots For this purpose, tailwind is to be calculated from the wind data measured in the on-air field anemometers and wind vanes according to the formula: (windspeed x cosine (runway heading minus wind direction))x-1 * AIP see glossary on page 3 Heathrow Airport Airspace & Noise Performance Q3 Report 217 Page 7

8 Day Noise Infringements Day Noise Infringements Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Night Noise Infringements Night Noise Infringements Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Page 8 Heathrow Airport Airspace & Noise Performance Q3 Report 217

9 Departure Track Keeping AD 2-EGLL (Page 28) For monitoring purposes, a departure will be deemed to have complied with the Noise Preferential Routeing (NPR) if, in the portion of flight below the appropriate vectoring altitude (see note 9 right), it is properly recorded by the airport s noise and trackkeeping (NTK) system as having flown wholly within the Lateral Swathe (LS). The LS is defined from the centre-line of the relevant route coded in the NTK system, based upon a map accredited for this purpose by the Department for Transport, by the closer to the centre-line depicted on the map of (a) a pair of lines either side, each diverging at an angle of 1 from a point on the runway centre-line 2m from startof-roll; and (b) a pair of parallel lines representing a distance of 1.5 km either side of the route centreline. For avoidance of doubt, the depicted route and LS may include curved sections representing turns. Note 9. Aircraft which have attained an altitude of 4 ft ( Heathrow QNH ) may be directed by air traffic controllers onto a different heading and commanders complying with any such direction will not by reason of so complying be deemed to have departed from the NPR. Track deviations by runway Period From 1/1/217 to 3/9/217 Runway Total Departures 217 Total Deviations 217 % Compliance R 67,463 1, L 68,735 1, R 42,824 4, L Totals 179,122 7, Heathrow Airport Airspace & Noise Performance Q3 Report 217 Page 9

10 % of On Track Departures by Flow and Route Current and Previous Year for 1/1/217 to 3/9/217 Easterly Month 9LBPK 9LBUZ 9LCPT 9LDET 9LGAS 9LMID Jan Feb Mar Apr May Jun Jul Aug Sep Jan Feb Mar Apr May Jun Jul Aug Sep Easterly Month 9RBPK 9RBUZ 9RCPT 9RDET 9RGAS 9RMID Jan Feb Mar Apr May Jun Jul Aug Sep Jan Feb Mar Apr May Jun Jul Aug Sep Page 1 Heathrow Airport Airspace & Noise Performance Q3 Report 217

11 % of On Track Departures by Flow and Route Current and Previous Year for 1/1/217 to 3/9/217 Westerly Month 27LBPK 27LCPT 27LDET 27LGOG 27LMID 27LWOB Jan Feb Mar Apr May Jun Jul Aug Sep Jan Feb Mar Apr May Jun Jul Aug Sep Westerly Month 27RBPK 27RCPT 27RDET 27RGOG 27RMID 27RWOB Jan Feb Mar Apr May Jun Jul Aug Sep Jan Feb Mar Apr May Jun Jul Aug Sep Heathrow Airport Airspace & Noise Performance Q3 Report 217 Page 11

12 Track Keeping Key Performance Indicator Period from 1/1/217 to 3/9/ Jun-97 Jan-17 Feb-17 Mar-17 Percentage on track Apr-17 May-17 Jun-17 Jul-17 Aug-17 Sep-17 West% East%-9RCPT Total%-9RCPT East% Total % Page 12 Heathrow Airport Airspace & Noise Performance Q3 Report 217

13 Minimum Climb Gradient Reporting Where the aircraft is a jet aircraft, after passing the point referred to in sub-paragraph (1) above, it shall maintain a gradient of climb of not less than 4% to an altitude of not less than 4 ft. The aircraft shall be operated in such a way that progressively reducing noise levels at points on the ground under the flight path beyond that point are achieved. 4% compliance score 1% 9% 8% 7% 6% 5% 4% % % 57 9.% % % % % % 3 74N 97.3% 2 32A 1.% 2 Aircraft types 4% compliance score, 217 to September Count of failures % % 1 74H 99.% 1 77L 99.5% % 1 L45 5.% % 1 77W 1.% 1 Count of Test 99.7% Count of failures Heathrow Airport Airspace & Noise Performance Q3 Report 217 Page 13

14 Oct 15 Nov 15 Dec 15 Jan 16 Feb16 Mar 16 Apr 16 May 16 Jun 16 Jul 16 Aug 16 Sep 16 Oct 16 Nov 16 Dec 16 Jan 17 Feb 17 Mar 17 Apr 17 May 17 Jun 17 Jul 17 Aug 17 Sep 17 Continuous Descent Approach (CDA) AD 2-EGLL (Page 28) For monitoring purposes, a descent will be deemed to have been continuous provided that no segment of level flight longer than 2.5 nautical miles (nm) occurs below 6ft QNH and level flight is interpreted as any segment of flight having a height change of not more than 5ft over a track distance of 2 nm or more, as recorded in the airport Noise and Trackkeeping system. * The CDA data is broken down into four time periods, Day (7hrs 23hrs), Night (23hrs 7hrs), Core night (233hrs 6hrs ) and the 6:hr (6hrs 7hrs) CDA Use during the day 7-23 CDA over 24 months. Three month Rolling Average line CDA% Page 14 Heathrow Airport Airspace & Noise Performance Q3 Report 217

15 CDA Use in Night 23-7 CDA 24 Months Rolling Average CDA% Oct 15 Nov 15 Dec 15 Jan 16 Feb 16 Mar 16 Apr 16 May 16 Jun 16 Jul 16 Aug 16 Sep 16 Oct 16 Nov 16 Dec 16 Jan 17 Feb 17 Mar 17 Apr 17 May 17 Jun 17 Jul 17 Aug 17 Sep 17 CDA Use in Core Night CDA 24 Months Rolling Average CDA% Oct 15 Nov 15 Dec 15 Jan 16 Feb 16 Mar 16 Apr 16 May 16 Jun 16 Jul 16 Aug 16 Sep 16 Oct 16 Nov 16 Dec 16 Jan 17 Feb 17 Mar 17 Apr 17 May 17 Jun 17 Jul 17 Aug 17 Sep 17 Heathrow Airport Airspace & Noise Performance Q3 Report 217 Page 15

16 CDA Use during 6-7 CDA 24 Months Rolling Average CDA% Oct 15 Nov 15 Dec 15 Jan 16 Feb 16 Mar 16 Apr 16 May 16 Jun 16 Jul 16 Aug 16 Sep 16 Oct 16 Nov 16 Dec 16 Jan 17 Feb 17 Mar 17 Apr 17 May 17 Jun 17 Jul 17 Aug 17 Sep 17 Joining Point AD 2-EGLL (Page 27-28) Between 6 and 233 hours (local time) where the aircraft is approaching runway 27 (L or R) and is using the ILS in IMC or VMC it shall not descend on the glidepath below an altitude of 25 ft (Heathrow QNH) before being established on the localizer, nor thereafter fly below the glidepath. An aircraft approaching without assistance from the ILS shall follow a descent path which will not result in its being at any time lower than the approach path that would be followed by an aircraft using the ILS glidepath, and shall follow a track to intercept the extended runway centre-line at or above 25 ft (Heathrow QNH). Between 233 and 6 hours (local time) where the aircraft is approaching runway 27 (L or R) and is using the ILS in IMC or VMC it shall not descend on the glidepath below an altitude of 3 ft (Heathrow QNH) before being established on the localizer at not less than 1nm from touchdown, nor thereafter fly below the glidepath. An aircraft approaching without assistance from the ILS shall follow a descent path which will not result in its being at any time lower than the approach path that would be followed by an aircraft using the ILS glidepath, and shall follow a track to intercept the extended runway centre-line at or above 3 ft (Heathrow QNH). Page 16 Heathrow Airport Airspace & Noise Performance Q3 Report 217

17 Between 7 and 23 hours (local time) where the aircraft is approaching runway 9 (L or R) and is using the ILS in IMC or VMC it shall not descend on the glidepath below an altitude of 25 ft (Heathrow QNH) before being established on the localizer, nor thereafter fly below the glidepath. An aircraft approaching without assistance from the ILS shall follow a descent path which will not result in its being at any time lower than the approach path that would be followed by an aircraft using the ILS glidepath, and shall follow a track to intercept the extended runway centre-line at or above 25 ft (Heathrow QNH). Between 23 and 7 hours (local time) where the aircraft is approaching runway 27 (L or R) and is using the ILS in IMC or VMC it shall not descend on the glidepath below an altitude of 3 ft (Heathrow QNH) before being established on the localizer, at not less than 1nm from touchdown, nor thereafter fly below the glidepath. An aircraft approaching without assistance from the ILS shall follow a descent path which will not result in its being at any time lower than the approach path that would be followed by an aircraft using the ILS glidepath, and shall follow a track to intercept the extended runway centre-line at or above 3 ft (Heathrow QNH). The NTK system is unable to take into account multiple fluctuations in pressure within an hour. This can lead to an increase in the reported number of LOWS in the summer months. Heathrow Airport Airspace & Noise Performance Q3 Report 217 Page 17

18 Rolling 2 years Joining Point Period from Oct 15 to Sep Percentage on Joining Point Oct 15 Nov 15 Dec 15 Jan 16 Feb 16 Mar 16 Apr 16 May 16 Jun 16 Jul 16 Aug 16 Sep 16 Oct 16 Nov 16 Dec 16 Jan 17 Feb 17 Mar 17 Apr 17 May 17 Jun 17 Jul 17 Aug 17 Sep 17 Month DayLates DayLows NightLates NightLows Day Joining Point Lates* Period from Oct 15 to Sep Oct 15 Nov 15 Dec 15 Jan 16 Feb 16 Mar 16 Apr 16 May 16 Jun 16 Percentages on Day Lates Jul 16 Aug16 Sep 16 Oct 16 Nov 16 Dec 16 Jan 17 Feb 17 Mar 17 Apr 17 May 17 Jun 17 Jul 17 Aug 17 Sep 17 Month * Lates and Lows see glossary on page 3 Page 18 Heathrow Airport Airspace & Noise Performance Q3 Report 217

19 Day Joining Point Lows* Period from Oct 15 to Sep Percentage on Day Lows Oct 15 Nov 15 Dec 15 Jan 16 Feb 16 Mar 16 Apr 16 May 16 Jun 16 Jul 16 Aug 16 Sep 16 Oct 16 Nov 16 Dec 16 Jan 17 Feb 17 Mar 17 Apr 17 May 17 Jun 17 Jul 17 Aug 17 Sep 17 Month Night Joining Point Lates* Period from Oct 15 to Sep Oct 15 Nov 15 Dec 15 Jan 16 Feb 16 Mar 16 Percentages on Night Lates Apr 16 May 16 Jun 16 Jul 16 Aug 16 Sep 16 Oct 16 Nov 16 Dec 16 Jan 17 Feb 17 Mar 17 Apr 17 May 17 Jun 17 Jul 17 Aug 17 Sep 17 Month * Lates and Lows see glossary on page 3 Heathrow Airport Airspace & Noise Performance Q3 Report 217 Page 19

20 Night Joining Point Lows* Period from Oct 15 to Sep Oct 15 Nov 15 Dec 15 Jan 16 Percentage on Night Lows Feb 16 Mar 16 Apr 16 May 16 Jun 16 Jul 16 Aug 16 Sep 16 Oct 16 Nov 16 Dec 16 Jan 17 Feb 17 Mar 17 Apr17 May 17 Jun 17 Jul 17 Aug 17 Sep 17 Month Go Around* Data Period from Jan 17 to Sep Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Go Arounds * Lates and Lows see glossary on page 3 * Go Around see glossary on page 3 Page 2 Heathrow Airport Airspace & Noise Performance Q3 Report 217

21 Night Noise Winter 28 Summer 217 Season Movement Quota Points Limit Winter (including carry over* from previous season) Summer Winter (including carry over* from previous season) Summer Winter (including carry over* from previous season) Summer Winter (including carry over* from previous season) Summer Winter (including carry over* from previous season) Summer Winter (including carry over* from previous season) Summer Winter (including carry over* from previous season) Summer Winter (including carry over* from previous season) Summer Winter (including carry over* from previous season) Summer Limits are set by the DfT The regime applies to a night period (23 7 hours) during which the noisiest types of aircraft (QC8 and QC16) may not be scheduled to land or take off. In addition QC4 types may not be scheduled to land or takeoff in the night quota period (233 6).In addition, between hours (the night quota period) there are further restrictions the number of aircraft movements are restricted by a movements limit and additionally there is a limit of noise quota points. These limits are set for each summer and winter season. Neither of these limits may be exceeded, ie if the movements limit were to be reached, no further movements would be able to take place even if quota points were still available, and vice versa * Carry over see glossary on page 3 Heathrow Airport Airspace & Noise Performance Q3 Report 217 Page 21

22 Summary of allocation usage Winter 26 Summer 217 Season Seasons Seasons QC points Movements Total Total Total Movements Exempt Not Not Not Quota movements carried carried QC points movements QC against counted counted counted Points limit over over allowed allowed value limit Delays DfT Emergency Limit Winter Summer Winter Summer Winter Summer Winter Summer Winter Summer Winter Summer Winter Summer Winter Summer Winter Summer Winter Summer Winter Summer Page 22 Heathrow Airport Airspace & Noise Performance Q3 Report 217

23 Summer Usage of QC Points (including carry over) Period from Summer 97 to Summer QC Points S97 S98 S99 S S1 S2 S3 S4 S5 S6 S7 S8 S9 S1 S11 S12 S13 S14 S15 S16 S1 7 Season Quote Count Limits Actual Use Summer Usage of Movements (including carry over) Period from Summer 97 to Summer S97 S98 S99 S S1 S2 Movements S3 S4 S5 S6 S7 S8 S9 S1 S11 S12 S13 S14 S15 S16 S17 Season Movement Limits Actual Use Heathrow Airport Airspace & Noise Performance Q3 Report 217 Page 23

24 Summer Season Weekly Pro Rata Usage Comparison (MV) 1 95 Percentage Pro rata Week number Summer 213 Summer 214 Summer 215 Summer 216 Summer 217 Target Summer Season Weekly Pro Rata Usage Comparison (QC) Percentage Pro rata Week number Summer 213 Summer 214 Summer 215 Summer 216 Summer 217 Target Page 24 Heathrow Airport Airspace & Noise Performance Q3 Report 217

25 Arrival and Departure information Runway Alteration Adherence Arrivals 96.% 95.% 94.% 93.% 92.% 91.% 9.% 89.% 88.% 87.% Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 217 TEAM after 7L Pure West Days only Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 217 Departures off landing Runway Jan-Jun Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 217 Heathrow Airport Airspace & Noise Performance Q3 Report 217 Page 25

26 Engine Ground Running The maximum total ground running exposure time over the night period from 23 to 7 hours must not exceed 15 minutes. Within the total 15 minutes, the maximum amount of ground running at high power must not exceed 6 minutes in any one night or exceed a rolling 3 day average of 2 minutes. Ground Idle Engine Runs 3 25 Numbers Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month 217 Day 217 Night High Power Runs (night all) 3 25 Numbers Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month 217 Day 217 Night Page 26 Heathrow Airport Airspace & Noise Performance Q3 Report 217

27 Total run time per night 3 25 Numbers Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month 217 Average number of run per night Numbers Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month 217 Heathrow Airport Airspace & Noise Performance Q3 Report 217 Page 27

28 Glossary of Terms AIP ANOMS Carry over CDA dba FLOPC Go Around IMC ILS KPI Lates and Lows LHR LS nm NATS NPR NTK QC QNH TEAM VMC Aeronautical Information Publication Noise, track keeping and complaints system Night restrictions are set on a seasonal basis. Up to 1% of a season's unused quota can be carried forward (known as "carry over") to the next season and up to 1% of a following season's quota can be anticipated Continuous Descent Approach A-weighted decibels Flight Operations Performance Committee A go around is an aborted landing of an aircraft which is on approach to the runway Instrument Meteorological Conditions Instrument Landing System Key performance indicators During the daytime the aircraft are required to be "established" on the ILS at 7.5nm from touchdown. This equates to approximately 25ft aal. At night the distance is extended to 1nm which equates to approximately 3ft aal. London Heathrow Lateral swathes Nautical Miles National Air Traffic Services Noise Preferential Routes Noise and Track Keeping monitoring system Quota Count The barometric pressure at sea level (QFE is the barometric pressure at the aerodrome) Tactically Enhanced Arrivals Mode. In order to help alleviate delay in the stacks, ATC may change from the published alternation schedule. In order to maintain minimum separation distances between inbound aircraft, maintain usual high safety standards and keep air traffic flowing, ATC may use both runways for arrivals for a short period. Visual Meteorological Conditions Page 28 Heathrow Airport Airspace & Noise Performance Q3 Report 217

29 Produced by Heathrow Airport's Airspace & Noise Performance team, Second Floor Meridian, The Compass Centre, Nelson Road, London Heathrow Airport, Hounslow TW6 2GW. Further information If you would like further information, please contact Airspace & Noise Performance team: By telephone: By noise@heathrow.com By post: Airspace & Noise Performance team Second Floor Meridian The Compass Centre Nelson Road London Heathrow Airport Hounslow TW6 2GW Website: Make an enquiry on our website: Please note that the freephone telephone number is an answerphone. Please leave your name, contact details and brief details of your enquiry. A member of the Airspace & Noise Performance team will contact you as soon as possible.