Why is that LAPD helicopter circling incessantly over your house in the middle of the night? Some folks, reasonably enough, get worried that a serial killer is lurking in their backyard. Others are simply annoyed by the noise and just want to get some sleep.

Helicopters, it's safe to say, are among Angelenos' biggest pet peeves.

See also: Helicopter Noise Law Would Protect Westsiders From Buzz Endured By the Rest of L.A.

And while this won't help your copter-induced insomnia, it might satisfy your curiosity. We recently spoke with Lt. Phil Smith, second in command at LAPD's Air Support Division. He was kind enough to give up the top five reasons why an LAPD helicopter is circling overhead:
]

Credit: facebook.com/LAPD911

Credit: facebook.com/LAPD911

First, a primer:

The division, a pioneer in aerial policing, was born in 1956, although it was in 1974 that the division expanded into the kind of atmospheric policing we see today. (LAPD even had an airplane in its fleet.) Other departments took notice of the pioneering program, while also taking advantage of low-cost military-surplus aircraft to build up their own air divisions.

With 17 choppers, LAPD's helicopter division remains the nation's largest such operation, and its Hooper Heliport downtown is the America's largest rooftop heliport.

For 20 hours a day LAPD usually has one airship in the Valley and one in the main L.A. basin, Smith says. On Friday and Saturday nights, that increases to one in the Valley, one north of the 10 freeway, and one south of the 10 freeway, he says.

The elemental answer to the question in the headline is that L.A. is an unusually large city geographically; the LAPD is, on a per-capita basis, a relatively small force. Helicopters are essential to helping the department respond to crime in roughly 470 square miles of municipal turf.

The department's main air ride, the American Eurocopter AS350 B2, can travel up to 178 miles per hour. Air units are often first on the scene of major emergencies.

Congress recently passed the Los Angeles Residential Helicopter Noise Relief Act but, alas, law enforcement and fire-rescue aircraft are exempt, leaving a major source of that noise unabated.

Your complaints aren't being ignored, but the department thinks that catching bad guys is more important than your aural comfort.

“Sometimes you're in the hills and you have a hot prowl burglary in progress,” Smith says. “There's no higher priority than that. You're going to upset neighbors if it's 2 or 3 in the morning. Our phone line here will ring. We don't enjoy it. It's our job. They will get out of there as soon as they can.”

Here's a list of reasons why that LAPD chopper is overhead:
[
5. Traffic stops. If there's nothing else more pressing going on, LAPD air units will circle over traffic stops, particularly if they involve wanted or allegedly armed-and-dangerous suspects. Officer safety is a high priority for the Air Support Division. “You never know who's behind the wheel of that car you're pulling over,” Smith says. “This lets whoever's in that car know we're here and we're watching.”

4. Property crimes. Being 2,000 feet above Los Angeles can be a good place to spot burglars, car thieves and taggers. As Smith said above, catching burglars red-handed is a big deal to the department. Last year air units used infrared search technology in such suspect searches 882 times, which is more than twice a day.

3. Perimeters. This duty probably accounts for much of your annoyance. LAPD helicopters are especially well positioned to help cops on the ground set up dragnets for an array of suspects – alleged burglars, gangsters who run from officers, robbers on the loose. Air units usually take command of these situations and order badges down below to take strategic positions in your neighborhood. This, unfortunately for you, can be quite a production. Air units responded to 1,433 of these kinds of calls in 2013, Smith said.

2. Pursuits. Actually, what we're talking about here is not just pursuits, but what the LAPD calls “followings,” too. Anticipating that a chase is about to break out because they just pulled behind a stolen car or wanted suspect, ground units will radio for air support. Most of the time, these things end with the vehicle pulling over. Sometimes, though, a suspect will drive so hard that the ground units back off. But virtually no car can beat a helicopter in L.A., so the pursuit carries on from the skies. Air units get over two-thirds of the department's pursuits and followings, Smith says.

1. Violent crimes in progress. Homicides, armed robberies, kidnappings, sex crimes – you get the picture. Cops call these kinds of reports “hot shots,” and they're broadcast on the department's highest-priority “Tac 1” radio frequency. The helos are your best bet for the fastest possible response. Often times, Smith says, the air unit will fly over expected escape routes to search for getaway cars. Of about 48,000 incidents air units responded to in 2013, Smith says, the helicopters were on scene before patrol cars were 14,500 times.

Bonus question: Why do LAPD helicopters fly in circles above crime scenes while news choppers hover in place?

Credit: facebook.com/LAPD911

Credit: facebook.com/LAPD911

It's not to make it difficult for someone to shoot at the birds. Smith explained that his choppers get lower than others (sometimes down to a high-rise height of 1,500 feet) so the officers inside can see what's going on. This, however, is dangerous. In the event of engine failure, a helicopter would have no momentum to glide to a crash landing. News choppers are so much higher that they don't face this problem. To generate some air speed, LAPD helos keep moving.

Smith:

Flying is all about altitude and air speed. If you lack one, you better have the other. It's strictly an aviation thing to keep moving. It does actually lower our noise signature because we're moving around. If we were hovering it would be very annoying.

Send feedback and tips to the author. Follow Dennis Romero on Twitter at @dennisjromero. Follow LA Weekly News on Twitter at @laweeklynews.

Advertising disclosure: We may receive compensation for some of the links in our stories. Thank you for supporting LA Weekly and our advertisers.