According to the FAA “SFO was the nation’s 11th busiest airport in 2015 with about 430,000 takeoffs and landings.” In addition we have one of the busiest airspace in the world with many airports in close proximity to SFO such as SJC, San Carlos Airport,  Palo Alto Airport, Oakland International Airport and Moffett Federal Airfield. Noise is a complex issue which requires regional solutions.



Jet Noise in the Peninsula


There has been a noise increase in the Peninsula over the last few years. Palo Alto hired a firm (Freytag and associates) to do a study on jet noise on two days 7 years apart. The study showed a comparison of Daily Noise Load (DNL) between 2008 and 2015 with an increase in jet noise in Palo Alto and in surrounding communities (see image below). The study found that “While the major flight tracks are somewhat similar, there appears to be considerably more flyover activity in the areas west and south of the City.”  The study was for Palo Alto but it is clear by looking at the image below that many communities have seen an increase in jet noise. 

Image Source: Freytag & Associates, Historical Noise Assessment for the City of Palo Alto

The study from Freytag and associates found that there was a 9.5% traffic increase over the 7 year period. Normally a 9.5% traffic increase would result in a DNL increase of .4 db (with all factors staying the same). However, southern parts of Palo Alto and parts of Mountain View had at least a 7.5 DNL db increase. The full study is available at this link.

Image Source: Freytag & Associates, Historical Noise Assessment for the City of Palo Alto

Enclosed below are 5 key reasons for why we are hearing more noise on the ground.


  1. Flight paths changed & moved

  2. Altitude dropped

  3. Traffic increased

  4. South Flow

  5. Other factors

Flight Paths Changed & Moved


In 2015 the FAA launched NextGen in Northern California and the SERFR flight path. Historically we had been flying BSR flight path for South arrivals. BSR was built to be optimized for noise efficiency. In the Peninsular BSR also flew over a lot more warehouses or commercial buildings which has a lower impact on people. The change in flight path was drastic for communities in the Santa Cruz mountains. In the peninsula the change was less significant than in the Santa Cruz Mountains, however the change is still worth noting.


Additionally the FAA rolled out NextGen which has more concentrated flight paths, however it is important to note that BSR was already concentrated, and there was an increase in vectoring. About half of SFO South Bay arrivals get vectored. Vectored flights go off the landing procedure and vectoring is used to space and sequence flights to ensure safe operations. Please see the image below from the FAA demonstrating the change in flight path between BSR and SERFR.

Image Source: FAA

Another change in flight path is that more flights are flying over Los Altos, Los Altos Hills, southern parts of Palo Alto, Mountain View and Sunnyvale. There was an increase in BDEGA West traffic which caused traffic to fly further south in order to deal with the congestion over the Peninsula. Please see the difference in the images below from 2008 to 2015 from  the study from Freytag and Associates:

Image Source: Freytag & Associates, Historical Noise Assessment for the City of Palo Alto

Altitudes Dropped


The lower planes fly, the louder they are perceived to be from the ground. With NextGen the altitude of flights dropped and the Menlo waypoint went from having a  5000’ visual approach and to an approach closer to 4000’. The result? A drop in 1000’ means almost twice the amount of noise from the ground. This helps explain why the study from Freytag and Associates saw such a tremendous increase in noise despite a limited increase in traffic.

Image Source: FAA

Traffic Increased


SFO traffic has not drastically increased over the last few years, however traffic increased significantly over the Peninsula due to changes in the BDEGA approach. The BDEGA  approach has two legs - East which flies over water, and West which flies over the peninsula.The jets that fly over the Peninsula are loud in two ways, they first bother all the residents throughout the peninsula on the way south, then the flights turn around in Palo Alto, Los Altos, and/or in Mountain View then bother the rest of the peninsula on the way back North. The amount of people disturbed by this approach is quite high.


According to the FAA, in 2005 43% of Flights that used the BDEGA approach used the West Leg, and 57% of flights used the East leg. The East approach flies over the Bay, and is much quieter than the West approach for Peninsula residents


In May 2016, 72% of flights that use the BDEGA Approach use the West Leg and 28% of flights use the East Leg. This has caused significant increase in noise over the Peninsula.

The question then becomes why are we using the East Leg less since it is so  much quieter? The answer is partly tied to runway usage. The East Leg and the DYAMD approach (This is the approach for flights coming from the East) share a runway (runway 28R). According to the FAA, that runway handles 51% of arrivals  and the rest of the jet are flying to runway 28L using the West Leg approach.


Despite minimal traffic increase into SFO, the Peninsula has had significant traffic increase because of the BDEGA  West approach.

Image Source: FAA
July 2014, SFO South Bay Arrivals & July 2016 SFO South Bay Arrivals (Image Source: FAA)

South Flow

Another factor in the jet noise in the Peninsula is the SJC traffic in South Flow. Normally flights depart North out of SJC and arrive from the South. During bad weather, or significant winds this is reversed and the peninsula get an increase in traffic over Sunnyvale, Mountain View and Palo Alto. Because San Jose International Airport is Class C airspace those flights must stay under the Class B airspace of SFO. As a result on South Flow days the peninsula has low altitude flights flying over highly populated areas.

According to San Jose Airport between January and August 2016, 16.1% of operations (an operation is a take-off or a landing) were under South Flow condition. This translated to 109.2 average Operations on South Flow Days.

In addition with new procedures, we have seen an increase in the concentration of the flights, and due to weather changes 2016 has had an increase in number of South Flow operations making South Flow a noise concern to many in the peninsula. 

Image Source: San Jose International Airport, City of San Jose

Surf Air & Other Factors

There are many other factors that impact jet noise over the Peninsula. Municipal Airports such as Palo Alto Airport and San Carlos Airport impact the plane noise, and one of the noise impacts has been the flight path for Surf Air.


Surf Air is a shared use charter airline that flies the Pilatus PC-12  NG into San Carlos Airport.  This airlines started flying into San Carlos airport on June 2013. On average Surf Air flies 18 round trips a day into San Carlos Airport. The noise of these planes is highly disturbing to the residents under the Surf Air flight path. Because of the Class B restrictions Surf Air must fly at low altitudes under SFO traffic. While the Pilatus PC-12 NG is a small 9 seater plane, these planes can still make almost as much noise as larger jets. Surf air’s GPS approach flies over Sunnyvale and residential neighborhood up the Peninsula. These 9 seater planes have the ability to increase noise for 140,000 people each time they arrive into San Carlos Airport.


Surf Air does not need to follow the same standards as larger planes since they are able to fly under part 135 of the Federal Regular Aviation Standards because they are flying a commuter plane of 9 seats or less. There are significant differences between part 135 standards, and part 121 standards airlines flying larger jets must follow. The standards vary in pilot qualification, crew member duty and rest requirements, airport and maintenance requirements. 

More Information:

Additionally it is important to note that Palo Alto Airport is the third busiest airport in the bay Area with an average of 172,0000 operations per year. An operation is a take-off or a landing. 


Image Source: San Jose International Airport, City of San Jose

Final Notes

There are a lot of myths when it comes to jet noise so I would like to point out a few key points to remember:


The flight paths for BDEGA, Oceanic arrivals and SERFR do not converge onto the MENLO Waypoint


Only non-vectored SERFR flights use MENLO waypoint. The BDEGA West approach doesn’t use  MENLO. Non vectored SERFR flights account for 15% of SFO Arrivals. There are groups that seek to move the MENLO Waypoint to reduce jet noise for parts of Palo Alto. However, moving the MENLO waypoint would shift noise to southern parts of Palo Alto, Los Altos, and Mountain View.

Jet noise is a regional issue and shifting noise doesn't address our regional problem. 


Over the recent years flight noise has increased, it is endemic to the Peninsula. Communities in Los Altos, Palo Alto, Los Altos Hills, Woodside, Mountain View, Sunnyvale and many more experience jet noise and have seen significant increases in jet noise. Since there are different flight paths over different neighborhoods each community is affected differently. It is also important to note that 50% of SFO south arrivals get vectored so even neighborhoods that are not under flight paths share the burden of jet noise.


Moving flights paths is not the answer to the jet noise issue because it is not fair to move noise to other communities, and shifting noise doesn’t address the noise issue. It is also not fair to not do anything about the jet noise. As a result we believe in finding solutions that reduce jet noise for all, and that are based on noise reduction instead of “noise shifting”. We believe that many incremental improvements combined can have a large impact. 


I have spent countless hours reading and rereading articles about jet noise. I am not an expert and bayarejetnoise are not experts. We ask you to do what's right which is to ask the FAA, our airports and elected officials to find solutions to reduce noise for all instead of shifting noise which doesn't address the jet noise problem for the region.

We ask for historical flight paths to be respected. Not only is it unfair to have flight paths move as people buy homes in certain communities. We also don't know the far reaching impacts of shifting flight paths. When they changed BSR the FAA didn't see a significant impact between the SERFR and BSR, yet communities overwhelmed SFO with noise complaints as soon as the flight path changed. In the end we ask for solutions that make things better and do no harm.

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