Stats, Psychology SMO's Annual Noise Workshop

The Santa Monica Airport Commission's annual noise workshop featured a mixture of straightforward statistics and complex psychology regarding flight operations at SMO and how people perceive the noise generated.

First, the numbers. Total aircraft operations were up in 2011 from 2010, but back down in the first half of this year.

In calendar year 2011, total airport operations increased more than 5 percent over 2010, to nearly 110,700. That's the first year-to-year increase since 2006 but a whopping 27 percent fewer than the nearly 152,000 operations in 2002. (An aircraft operation is one takeoff or one landing).

Propeller aircraft operations jumped 5.5 percent in 2011, to just over 94,700, while jet operations went up by 2.5 percent, to 13,180. But the numbers for both aircraft types remained about 28 percent lower than their highest marks of the past 10 years.

Helicopter operations jumped nearly 21 percent in 2011, to just under 2,800. That's still one-third fewer than the peak year of 2005.

The numbers dropped in the first half of 2012, as total operations, propeller and jet operations each fell 10 percent to levels like the first half of 2010, which were the lowest of the period 2002-2011.

Santa Monica Airport in the Eye of the Storm

Noise violations at SMO rose from 116 to 135 in 2011, meaning the violation rate remained at around one-tenth of 1 percent. The vast majority of violators were first-timers, who received warnings. Fifteen other violations each brought fines of $2,000. Two aircraft were banned for repeated noise violations.

Although landings during the nighttime voluntary curfew increased 8 percent, curfew departures declined, and only three of the 18 were true violations. The others were ambulance or law enforcement flights.

Did residents complain about airport noise? Yes and no. SMO's staff reported nearly 3,700 "community inquiries" from 366 residences. But nearly 80 percent of the complaints were from 30 residences. Nearly 12 times as many complaints were filed a year earlier, most due to the Federal Aviation Administration's test change in the west-bound departure pattern for some planes.

The biggest surprises at Monday night's meeting came from noise consultant Vince Mestre, an expert in how sound is measured and perceived.

While most people believe they know what's loud and what's not, Mestre declared: "People are not sound level meters,'" and their noise perception is affected by non-acoustic factors.

One example: your annoyance level can vary based on whether you believe the noise source (an airport?) belongs where it is. What's more, people respond differently to aircraft noise than to street noise at the same level.

Likewise, Mestre said, an unfamiliar noise will wake you more quickly than a familiar sound of the same intensity.

Even more complicated, he said, is determining whether noise hurts you physically. Studies show very mixed results on whether noise affects blood pressure or your likelihood of having a heart attack.

Even mechanical noise monitors have their limits. Mestre said SMO's monitors are "state of the art" but can't absolutely distinguish between aircraft noise and a power mower.