Of particular concern, NextGen moved the flight path of planes arriving from the south at SFO more to the east, putting aircraft over some coastal residents in the Santa Cruz area who had not previously been in the flight path. The previous flight path, called Big Sur, was replaced with SERFR, which put more and lower air traffic over Palo Alto.

Thousands of residents, particularly in Palo Alto where three flight paths cross, were in an uproar after the FAA implemented NextGen, a program it launched in 2015 designed to overhaul the air-traffic system and free up airspace by putting planes in narrow corridors. That system has created increased noise levels by lowering altitudes, putting planes in a narrower travel band and increasing the frequency of aircraft flying over specific areas.

U.S. Reps. Anna Eshoo, Jackie Speier and Sam Farr, convened the temporary 12-member Select Committee, which held 10 public hearings and developed a 35-page report of recommended changes. It submitted the report to the FAA in October 2016 . The longstanding SFO Roundtable, which represents cities in San Mateo and San Francisco counties, submitted a separate recommendations report.

The change from the so-called SERFR flight path, which goes from San Francisco International Airport over the Santa Cruz Mountains before traveling southwest, was one of 104 responses the FAA addressed following recommendations made by two airplane-noise committees: the Select Committee on South Bay Arrivals and the San Francisco International Airport/Community Roundtable.

The Surf Air Pilatus PC-12 plane is parked outside the Surf Air terminal at the San Carlos airport on Oct. 17, 2014. Three U.S. representatives are looking to compile a South Bay Airport Roundtable that would address ongoing regional aircraft noise issues. Photo by Veronica Weber.

The Surf Air Pilatus PC-12 plane comes in for arrival at the San Carlos Airport on Oct. 17, 2014. The Federal Aviation Administration is evaluating 52 percent of recommendations brought by the Select Committee on South Bay Arrivals. Photo by Veronica Weber.

The report also outlines a broad timetable for resolving each of the recommendations, ranging from weeks and months to years, depending on how many layers of study, review and rule-making each will require. The FAA can address some of the proposed changes without formally changing federal rules; others must go through cumbersome evaluation and adoption.

The agency is evaluating 52 percent of the additional recommendations. Another 21 percent were either not endorsed by the Select Committee or are deemed outside the FAA's purview.

The FAA has characterized an additional 14 percent of recommendations as "feasible," which could be implemented in either the short term (less than two years) or long term (more than two years). Those recommendations include routing planes down the bay at night and modifying so-called restricted Class B airspace so that planes can use quieter idle-power descents rather than noisier speed brakes.

The Select Committee recommended creating a new arrival route over the Big Sur ground track and developing a new route as an Optimized Profile Descent, which would enable aircraft to descend in a quieter, idle-power setting instead of using "speed brakes" that require noisier throttling. The FAA characterized the new route as "feasible" and said it has completed developing its conceptual route -- the first phase of its development. The FAA will create a working group to design the route and have an environmental and safety review before reaching a final decision. The entire process is anticipated to take 18 to 24 months, according to the report.

The committee recommended establishing an ongoing, permanent entity to address regional aircraft noise and to evaluate how changes to NextGen are functioning. U.S. Reps. Anna Eshoo, Jimmy Panetta and Ro Khanna are pushing ahead with establishing a committee in Santa Clara County that would be similar to the SFO Roundtable. The representatives asked Joanne Benjamin, interim executive director of the Cities Association of Santa Clara County, for assistance in forming the long-term forum, according to a June 28 letter . The Cities Association represents 15 cities in the county.

The Select Committee has recommended noise-measurement modifications to more accurately consider the noise experienced by people on the ground. Noise levels are currently taken cumulatively within a 24-hour period and don't accurately measure the true impact experienced by residents. The U.S. Congress would require the FAA to adopt the new measurements under the committee's recommendation. The FAA should also monitor and document noise exposure of any proposed solutions before and after they are put in place so there is a measurement of how well they are working.

The FAA is not addressing several recommendations that would measure the impacts of any of the changes it makes and lists those as "Recommendations which were not the FAA's action." It did not address ways to ensure compliance, monitor noise before and after the new procedures are implemented or add regional noise-monitoring stations.

The FAA said that several recommendations are not within its purview. It has directed to the aircraft industry concerns about retrofitting a certain class of aircraft with wake vortex generators to reduce noise. Airbus A320 aircraft built before 2014 make a whistling or whining sound on approach due to the design of the wing. Roughly 35 percent of the aircraft arriving and departing SFO need the retrofit.

Some recommendations cannot be addressed until the FAA completes another recommendation. A proposal to raise the altitude on a Mineta San Jose International Airport arrival route, for example, can't be evaluated until the FAA completes a design for a Big Sur overlay route because of the interaction between the two paths, the agency wrote.

The FAA has addressed this concern "to the extent feasible." The agency is currently evaluating altitude restrictions below 8,000 feet to all vectored flights in the Woodside beacon area and prohibiting any overnight crossings at Woodside below 8,000 feet. Timeline: More than two years.

In July 1998, the FAA instituted a procedure requiring flights over the Woodside navigational beacon to be no lower than 8,000 feet above sea level, “traffic permitting.” Numerous reports from the community claim the planes are currently not honoring the 1998 agreement. The planes are flying at much lower altitudes including at night when residents are particularly sensitive to noise. Some flights are allowed to come in at 6,000 feet over this point, including overnight. An estimated 36 percent of Oceanic flights arriving at SFO between 1 a.m. and 6 a.m. fly over the Woodside point.

Under NextGen, the arrival path became more concentrated; with vectoring moving southward. About 76 percent of the BRIXX flights are vectored or taken off the flight path prior to the point where the two flight paths intersect. These changes resulted in complaints from residents in affected areas.

The northern arrival path into San Jose International Airport, called BRIXX, runs down the Peninsula, roughly over La Honda and Boulder Creek before turning and flying south and then east and north for a final approach. The path intersects with the southern-arrival path (SERFR) going to SFO.

The Select Committee recommended that planes come in at a slightly steeper approach to allow them to begin their descent at a higher altitude, which would reduce noise. The committee recommended that while still ensuring the safety of the aircraft, the altitude should be increased for all flight paths in and out of SFO. The FAA is currently evaluating the recommendation. Timeline: More than two years.

The Committee had a number of recommendations: raising the altitude over the waypoint, vectoring air traffic at a higher altitude and moving the waypoint to another location, among others. The FAA is currently evaluating raising the altitude of vectoring aircraft over MENLO above 5,000 feet. It is also evaluating establishing different points of entry over land at high altitudes to the final approach on the SERFR arrival or its replacement, such as a different waypoint east or north of MENLO. Timeline: More than two years.

The designated point over which all of the planes from the south must pass, the MENLO waypoint, is located several city blocks south of the intersection of Willow Road and U.S. Highway 101. Planes currently cross at 4,000 feet, although by an agreement arranged more than a decade ago through Eshoo and then-Palo Alto Mayor Gary Fazzino, planes were supposed to fly no lower than 5,000 feet.

The Committee recommended greater use of the Bodega East leg for planes. From 11 p.m. to 6 a.m., when air traffic is lighter, virtually all such aircraft should come in using the San Francisco Bay approach. The FAA is evaluating feasibility. Timeline: More than two years.

Planes using the East leg create dramatically less noise versus aircraft using the West leg, which flies over the highly populated Midpeninsula, and particularly Palo Alto. Air traffic was almost evenly split between the two legs, but in May 2016 roughly 70 percent of the arriving aircraft began flying over the Midpeninsula.

Planes arriving from the north currently use the Bodega path, in which planes reach a point roughly over Daly City and continue south flying past SFO, using either the Peninsula (the so-called West leg) or San Francisco Bay (the East leg), to make a U-turn for landing on two runways. The Bodega East leg shares the final approach path into SFO with aircraft arriving from the east.

Vectoring is common over Menlo Park, East Palo Alto, Palo Alto and Mountain View from the east (Oceanic), north (Bodega) and south-arriving flights. Roughly 50 percent of the arrivals from the south are currently vectored so they will be sequenced and spaced properly for arrival. The FAA is also evaluating raising vectoring altitudes over the Midpeninsula. Timeline: Less than two years.

The FAA is working with the San Francisco Roundtable to identify locations for vectoring with the least impact over land. New vector locations could be over the Pacific Ocean or San Francisco Bay.

The FAA has been working on this issue through a variety of means, including discussions with SFO to update its Fly Quiet program. The FAA has also worked with the airport to keep nighttime flights on a designated nighttime route as much as possible to reduce vectoring, a kind of "holding pattern" that puts planes off their direct descent route when approaches are backed up. Flights would be directed down San Francisco Bay rather than over land as the preferred procedure during Noise Abatement Procedure hours through 6 a.m. Timeline: Less than two years.

The FAA found it feasible to change the shape of the restricted airspace around SFO, known as Class B airspace, which is designed to ensure a higher level of safety for arriving aircraft. The agency proposed altering the size or shape of the airspace so that pilots wouldn't need to use altitude and speed adjustments to stay in the prescribed zone. Timeline: 3 years, not including developing a staff study.

The letter proposes creating a permanent aircraft-noise mitigation committee to include representatives of cities in Santa Clara and Santa Cruz counties, San Jose International Airport and SFO. The letter recommends that the FAA agree to provide technical assistance as needed, and that the San Jose airport host and staff the meetings. The South Bay Airport Roundtable would also have a subcommittee to work together with the SFO Roundtable on regional and overlapping-noise issues.

FAA report looks to change SFO-arrivals path

Federal agency evaluates the feasibility of 104 recommendations submitted in October