Sunday, December 4, 2016

Airport Noise over South Bay; Internet Links - 2

Some more random links and thoughts:

Measuring Sounds:

It might help others understand the noise level people endure if they had some accurate measurements such as one of airplane noise and the other of highway traffic as it sounds from a footbridge over 280 or 85 or a truck rumbling by or something else unpleasant they can relate to.

Sound measurement apps for smartphones (2014):
with 2016 follow up study:

Search on Amazon for "Sound-Measurement" for a list of sound measuring instruments such as seen below (click to enlarge):

Addressing the City Council:

In addressing the city council be respectful so you get the same respect back.  If you want to make a presentation longer than the normal 3 minutes, you might ask the mayor in advance.  

Two old sayings apply in making presentations to council:  "You catch more flies with honey than with vinegar" and "Brevity is the soul of wit".

After the last council meeting, Mayor Hendricks stayed after adjournment answering questions about airport noise and what he was doing about it for almost two hours - longer than the meeting itself.  He didn't have to do that.  He has a full time job and a family besides being mayor.  I firmly believe he is doing everything he can and putting a lot of time into it, but the Federal Govt. does not move fast.  The federal elected officials like congress members and senators have the most influence since they vote on funding for the FAA.

Other's Personal Views and their further links tools from the online discussions:
"Just want to let you know if you scroll to the bottom of the page through this link:
you will find a web tool and a step by step Demo that can make complaint filing less painful.  Web Tool Step by Step Demo (New 11/21/2016)- How To Capture An Airplane with Webtrak or FlightRadar Within 5 Seconds
Basically you can find the flights that bother you from the google sheet and copy/ paste the information into the tool, then an email to FAA will be generated, you will need to enter your comments, then send it out. The complaints to SJC will have to be filled out on their web form but if you save your personal information on your google account, you won't need to fill out those information each time. Hope it helps!"
"I was on a flight, UA1957, that landed at SJC at 11:13 am on 11/26. During the descent/approach over Cupertino and Sunnyvale it was at a noticeably lower altitude than I had ever previously experienced in 25+ years of flying into SJC. It was the best view of the Serra Park neighborhood I ever had - not that I wanted it.
I replayed it on the webtrak site, and it crossed over Nimitz and Hollenbeck/Fremont intersection at 2900 ft at 11:08am.  the change in approach paths is noticeable and real."

An article on San Mateo airplane noise and "NextGen" which seems to partially explain why noise is so much worse now:

1.  The key point from the above article is that they are flying at 4,000 feet and even 3,000 feet vs the former 5,000 feet.  Changing from 5,000 feet to 4,000 feet results in a 56% increase in "loudness", 5,000 feet to 3,000 feet means 177% increase.  Math part: 4,000 vs 5,000 doesn't seem like a huge difference (only 20% lower) but sound travels outward in a spherical form (inverse square law) so the increase in sound intensity (loudness) is not 5/4 but (5^2)/(4^2) (i.e., 5 squared over 4 squared) which is an increase of 56%.  For 3,000 feet this becomes 5 squared over 3 squared which results in a 177% increase.

2.  The 2nd, related, point is that the Doppler effect makes the noise sound higher in pitch as the planes approach.  We don't usually like high pitched sounds - think screeching metal on metal of trains braking.  By flying lower, the Doppler effect is increased since their relative movement seems faster.    To explain the last point, when you see a car moving from a high building it appears to move very slowly but if you are right next to it, it appears to move very quickly.  So the Doppler effect is increased and they sound at a higher pitch.