The existing noise management program at SFO combines elements of the existing approved Part 150 Noise Compatibility Plan, City/County of San Francisco Resolutions, goals of the San Francisco International Airport/Community Roundtable and air traffic control requirements to ensure the safe and expeditious handling of air traffic. These procedures are part of a runway use program and participation by pilots that is part regulation and part voluntary. While safety is paramount to all air traffic operations, noise sensitivity to the surrounding communities is also of key importance. The following information describes the integration of noise abatement procedures with Airport and air traffic control procedures.
The FAA has a primary function to determine under what conditions flight operations may be conducted without causing degradation of safety. Under ideal conditions, aircraft takeoffs and landings should be conducted into the wind. Considerations such as runway length, approach aids, noise abatement, and other factors often dictate that aircraft operations be conducted in a specific manner.
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Reducing nighttime aircraft noise is a key goal of SFO's Nighttime Preferential Runway Use Program. The SFO Nighttime Preferential Runway Use Program is a voluntary program that was developed in 1988. Between the hours of 10:00 p.m. and 7:00 a.m.- aircraft operators are asked to comply with the program when conditions allow.
Within the program, late night hours are especially critical. The program tries to maximize flights over water and minimize flights over land and populated areas between 1:00 a.m. and 6:00 a.m. Fortunately, because airport activity levels are lower late at night, it is feasible to use water-facing departure procedures more frequently than would be possible during the day. While the authority to control aircraft movements at airports lies solely with the FAA, airports can recommend the use of certain runways for noise abatement purposes through the development of runway use programs.* At airports with multiple runways, a "preferential" runway use program may be developed establishing a specific use for landing or takeoff during certain times of day or night.
SFO operates on two sets of parallel runways for both arrivals and departures. Based on this runway configuration, there are three preferred nighttime preferential runway procedures:
- The primary goal of the program is to use Runways 10 L/R for takeoff because they offer departure routing over the San Francisco Bay which will reduce the noise impacts over the communities surrounding SFO.
- When departures from Runways 10 L/R are not possible, the second preference would be to depart Runways 28 L/R on the Shoreline or Quiet Departure Procedures. Both of these procedures incorporate an immediate right turn after departure to avoid residential communities northwest of SFO.**
- The third preference is to depart on Runways 01 L/R. While this procedure directs aircraft over the bay, jet blast from these departures affects communities south of SFO.
The least desirable departure procedure at SFO is a straight-out departure on Runways 28 L/R. These departures overfly densely populated communities immediately west of SFO and are discouraged at all hours.
* The noise metric used by the airport, and State of California, CNEL, traditionally weights both evening and late night noise more heavily to account for this added disturbance.
** FAA Order 8400.9 documents the safety and operational criteria for the development of Preferential Runways for noise abatement at U.S. airports.
The Precision Runway Monitor (PRM)/Simultaneous Offset Instrument Approach (SOIA) is a marriage of existing approach technologies that when applied together, as at San Francisco International Airport, can provide a delay reduction of up to 25%.
During optimal weather conditions SFO may accept 60 arrival operations per hour to Runways 28L and 28R, two runways which are separated by 750 feet measured from the runway centerlines. During weather conditions with low clouds, the FAA requires that arriving flights must be separated by a minimum of 3,400 feet at any given airfield. Because the distance between Runways 28L and 28R does not meet this required threshold, a single stream of traffic is directed to one runway, cutting the number of operations in half. Runway 28L utilizes a straight-in conventional Instrument Landing System (ILS) approach with Precision Runway Monitoring (PRM) separation. This separation is provided by a controller at the FAA's Northern California Terminal Radar Approach Control (TRACON or NCT), monitoring a special PRM radar with highscan rates. The approach to Runway 28R is the offset approach flying a Localizer Directional Air (LDA)/Distance Measuring Equipment (DME) approach with PRM separation. This approach may be flown down to a ceiling (cloud cover) of 2,100 feet with four miles of visibility.
Ocean Tailored Arrivals
Ocean Tailored Arrivals (OTA) began as a test program between Boeing and NASA Ames research center to increase air traffic and aircraft fuel efficiencies of flights arriving over the Pacific Ocean to SFO. The OTA procedure allows aircraft to use what is called a continuous decent approach (CDA), which means that an aircraft descends to the airport at a continuous, constant rate. Using a CDA approach reduces the amount of fuel needed due to the use of idle throttle on the descent. A typical arrival procedure requires an aircraft to descend, fly at an altitude, then descend again in a stair-step fashion which can lead to increased use of the throttle over noise-sensitive land uses.
The OTA procedure is used during early morning hours when there are few operations. Aircraft arriving from the Pacific Ocean fly a constant rate of decent; aircraft track to the Woodside VOR navigational aide, which is an aide located on the ground in the hills above the City of Woodside that aircraft track to, crossing over the navigational aide at or above 7,000 feet above ground level. At this point aircraft continue to track navigational points called way points; these are locations in space identified by latitude and longitude. These waypoints guide an aircraft to the runway.
Run-ups of mounted aircraft engines for maintenance or test purposes are prohibited between the hours of 10:00 p.m. and 7:00 a,m. daily except as provided below. Aircraft engine run up activity is restricted during nighttime hours because at night the ambient, or background noise, is lower than during the day. When ambient noise is lower, noises that occur above the background noise seems louder. An idle check of a single engine is allowed under the following conditions:
- An idle check of a single engine not to exceed five minutes in duration may be conducted in the specific airline lease hold area. If more than one engine is to be checked, each engine must be checked separately and the cumulative duration of the idle checks cannot exceed five minutes.
- An idle check of a single engine or multiple engines (checked separately) which will exceed five minutes in duration will be accomplished in the designated run-up. For purposes of noise abatement monitoring, this will be considered a power run-up.
- Engines, when required, may be idled to accomplish compass checks on the compass rose located at the approach end of Runway 19R
As part of the aircraft operations and noise monitoring system upgrade, a ground run up monitoring system was installed at SFO. This system gives the Airport the tools to remotely monitor aircraft run up activity via motion detection cameras and noise monitoring stations 24 hours a day. This allows SFO to detect when ground run up activity occurs at unauthorized airfield areas and provides a means for Operations staff to log and verify ground run up activities. Currently when aircraft conduct run up activities between 7:00 a.m. and 10:00 p.m. aircraft use a number of locations on the airfield. The selection of the location depends primarily on weather conditions and space availability.
- At the Domestic terminals the use of APUs is prohibited between the hours of 10:00 p.m. and 6:00 a.m. except 30 minutes prior to departure, when passengers are aboard, or it is needed to test other aircraft equipment.
At the International terminal the following procedures apply:
- Aircraft scheduled to be at a gate in Boarding Areas A and G for more than 45 minutes between the hours of 7:00 a.m. and 10:00 p.m. are required to use 400Hz ground power and pre-conditioned air, where available. APUs are not authorized without prior permission from Airport Operations, during the use of ground power and preconditioned air until 30 minutes prior to push-back.
- All aircraft scheduled to be at a gate between 10:00 p.m. and 7:00 a.m. are required to use 400Hz ground power and preconditioned air, where available regardless of duration at the gate. APUs are not authorized without prior permission from Airport Operations, during the use of ground power and pre-conditioned air until 30 minutes prior to push-back.