Recently a girlfriend asked me why the police helicopter was constantly circling over his home in the center of the night. He asked why they didn’t just fly ago and soon or hover up high. Together a chopper pilot, there room some good reasons why us circle.
You are watching: What does it mean when a helicopter is circling
Helicopters use less power come fly in ~ 60 knots in a circle end a location contrasted to the power forced to hover. This permits for longer time top top station and also gives the occupants or pilot whole 360° check out of the scene to film, observe or recon before making method to land.Some of this these may start to make a small sense therefore now allows look in ~ the details that why helicopters circle rather than carry out something else.
Why perform Helicopters paris or Circle end My House?Police & news space the two most common helicopters that may be seen circling over your house. Miscellaneous on the soil in your vicinity is of interest to the crew and the helicopter is making use of its camera to movie or find the area. Circling enables the event to remain in watch of the crew at all times.When the thing in inquiry is stationary, like a roadway traffic accident or a criminal trying to hide the best way to save that area in see at every times is for the helicopter come circle or orbit about it.Most police or news pilots will collection up an orbit in between 500ft-1000ft above the object and fly approximately 60 knots(kts) airspeed. This offers an altitude that is high sufficient to be able to clearly see the object by eye, while maintaining a safe height over the bordering area. This height also helps to minimize the amount of noise people will hear in your home, particularly at night.Because the helicopter has a camera mounted on its sleep or next a an excellent majority of the time the camera operator is the one wanting to see or track the object. To execute that the pilot will fly the orbit for this reason the camera operator is top top the inside of the circle. This helps the camera operator store the shoot framed with minimal work because the pilot is may be to quickly keep the thing in vision by using a mixture of spring outside and also looking in ~ the camera screen.
Why does A Helicopter Circle prior to Landing?Circling in a helicopter is the best way to view an area from all sides come look at the landing spot. When a helicopter pilot is landing in ~ an unprepared area prefer a baseball diamond, city park, or also a hole in the trees the end in the remote parts of the country, they have to look and assess several factors:Wind – Landing into the wind is the wanted choice, yet will the strategy path in and out that the landing website be clear of objects come facilitate this?Wires – space there wires across or near the landing spot. Pilots usually look for supporting structures prefer poles or towers together wires have the right to be impossible to see at timesObjects – Trees, towers, structures, people, debris. Are any of this in the way during approach, landing, or departure?Sun – will certainly the glare the the sunlight on the home window obscure vision as soon as approaching to land?Shape – What is the form of the clean area come land, long and also skinny or large open? This have the right to dictate the direction of method to landSlope – Is the floor sloping where the pilot desires to land. Many helicopters have between a 5-10° slope landing limitationLanding spot – Is the landing spot clear of obstructions, debris, human being etc
All the these determinants need to it is in assessed before the pilot formulates the best setup to for sure approach, land, and also depart the spot. The easiest means the pilot deserve to do this is by making use of 2 orbits:High Orbit – typically 500ft above the spot to look for the key objects, asses wind, and also look at the approach and also departure pathsLow Orbit – generally 100ft – 200ft over the spot for final observations the the exact landing pointA good, experienced pilot can do every one of this in 1-2 orbits while descending to start the approach. Most orbits will be done clockwise as most helicopter pilots sit top top the ideal side that the helicopter. This will provide the pilot the best view that the entire area.Flying one orbit also helps come views possible hidden obstacles. Shadows and sun have the right to really hide objects from up high and depth perception deserve to be really obscured. By taking the time to circle the landing spot, the pilot gets the best chance to discover anything the could cause them problems once on final approach.
Circling Vs HoveringThe one point that renders helicopters distinct is the they deserve to hover. They have the right to hover numerous feet turn off the soil or, if sufficient power is accessible they have the right to hover thousands of feet in the wait – for this reason why don’t pilots just float to look at a spot or object?
HoveringHovering have the right to be a great way to check something and also the main ways the hovering is used rather of orbits are:Tall structures – as soon as trying to look down into the street the is surrounding by tall buildings a high float is a much better option. If a helicopter orbits, the surrounding structures can block the view.By maneuvering the helicopter into the finest stationary place it permits the object to be it was observed easily.Limited Airspace – When numerous news helicopters like to covering an occurrence the pilots can talk to one another and also each host their position. I observed this take place at Boeing ar near Seattle as soon as 6 news helicopters all satellite hovering come the political parties of the runway as soon as the new Boeing 787 Dreamliner flew in for the first time.By doing this, Air traffic Control enabled them to gain closer and each news channel obtained a perfectly clean shot of the approach and landing of the plane.
CirclingHere room the most usual factors why paris an orbit at approximately 60 kts airspeed is excellent in a helicopter:Power compelled – Hovering a helicopter calls for the most amount of strength from the engine/s, particularly when lock are about 20ft-60ft above the ground. By paris at 60kts it calls for the least amount of strength from the engines, hence reducing fuel consumption.
A typical Helicopter ‘Power required Curve’
When the helicopter is at a slow-moving speed the rotor system has to produce all the lift just from the engine power. As the helicopter begins to advice the main rotor system starts get a hand from aerodynamics and the power compelled to keep the helicopter paris reduces.At 6o knots this is as soon as the power compelled to paris is in ~ its lowest. Once the helicopter goes previous this speed, traction on the aircraft starts to require much more power to get rid of it and also push the helicopter v the air.By flying orbits at 60 knots it allows the helicopter to use the the very least amount that power, which means the least amount that fuel burn, hence the pilot is able to continue to be on step much longer than simply sitting there in a hover.
H/V DiagramThe H/V or height Velocity chart is a diagram approve by the helicopter manufacturer the tells the pilot when a helicopter could be landed safely if their engine to be to stop. This diagram is based upon height above the ground and also airspeed.Height and airspeed room the two finest friends to a pilot in one engine fail situation and also having both are an excellent but what if you only have actually one…If I have lost you, simply hang in there and also I will explain:If the plane is low and also slow as soon as then engine stops working then the possibilities of the helicopter making a for sure autorotation landing room slim.If the helicopter is low and also fast and the engine quits the pilot might be can not to slow the helicopter under in time before it sinks and also contacts the ground.
In the diagram above, to avoid these scenarios, the pilot will accelerate to about 50 knots while continuing to be 5-10ft above the ground then begin to climb away. By doing this the pilot stays clear of the red ‘Avoid’ areas.So exactly how does his apply to a circling helicopter? among the concerns my friend asked was why not just hover? In the diagram, to hover (0kts) the helicopter would need to be over 800 feet high to have the ability to make a for sure autorotation landing, and that’s noted there is an open up area quite close by.By circling approximately at 60 kts the pilot walk not have to worry about the H/V Diagram and also if the engine to be to quit, the ideal autorotational rate for many helicopters is 60 kts, which lock are already at. Over there may also be more chances of detect an open landing location as the forward speed they have permits them to cover more distance throughout the glide.
To FinishThe main reasons why helicopters one overhead are to burn less fuel and stay on station longer, give the residents the best view the the scene, and also to save the helicopter in a for sure flight condition if the engine to be to ever quit.It is additionally a lot easier to paris in a steady orbit in ~ 60kts than try to maintain a high float without visual referrals to allow the pilot understand if they room drifting or changing height.
Further Reading:If you discovered this article interesting and also would favor to keep reading, I extremely recommend the following articles from my blog:Can Police Helicopters Detect thrive Operations? Worried?!This is What Police Helicopters in reality Do!This Is Why Helicopters space So Loud! A Pilot Weighs in!Do Helicopter Pilots stay Parachutes?This is Why a Helicopter MUST have actually 2 Rotors, or walk It??
Rick JamesI am an aviation nut! I"m an ATP rated helicopter pilot & former flight instructor through over 3000 hours spanning 3 countries and also many different flying jobs. Ns love aviation and also everything about it. I use these write-ups to pass on cool facts and information come you whether you are a pilot or simply love aviation too!If you desire to know an ext about me, just click on my picture!
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Hi, I"m stack James and also I am an aviation nut! I"m an ATP rated helicopter pilot & former flight instructor v over 3000 hrs spanning 3 countries and also many various flying jobs. This website was created to help pass ~ above information and also knowledge that all things aviation!About Me
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