While the sound of a helicopter may have many rushing to their windows to identify the make of the aircraft, the majority of people feel an intense sense of annoyance, or more accurately, disruption or anxiety.
So, what is it about helicopters that is so intrusive, placing people and animals outside their comfort zone?
The answer is Infrasound otherwise known as the 'fear frequency'.
It's all explained in the following article 'The Fear Frequency' by Mark Pilkington ( The Guardian 6 Oct 2003)
"Have you ever wondered what a ghost sounds like?" Engineer Vic Tandy may already know. "The key here is frequency: 19hz is in the range known as infrasound, below the range of human hearing, which begins at 20hz. Engineer Vic Tandy learned that low frequencies in this region can affect humans and animals in several ways, causing discomfort, dizziness, blurred vision (by vibrating your eyeballs), hyperventilation and fear, possibly leading to panic attacks".
In the early 1980s, Tandy was working in a laboratory designing medical equipment. Word began to spread among the staff that the labs might be haunted, something Tandy put down to the constant wheeze of life-support machines operating in the building.
One evening he was working on his own in the lab when he began to feel distinctly uncomfortable, breaking into a cold sweat as the hairs on the back of his neck stood on end. He was convinced that he was being watched. Then, out of the corner of his eye, Tandy noticed an ominous grey shape drifting slowly into view, but when he turned around to face it, it was gone. Terrified, he went straight home.
A more recent investigation took place in an allegedly haunted 14th-century pub cellar in Coventry, where people have reported terrifying experiences for many years, including seeing a spectral grey lady. Here Tandy also uncovered a 19hz standing wave, adding further evidential weight to his theory.
In an interesting parallel, researchers have recorded that, prior to an attack, a tiger's roar contains frequencies of about 18hz, which might disorientate and paralyse their intended victim. Is this the sound of fear itself?"
We have uploaded some articles of interest on the subject here. You can listen to the sound of 20 Hertz, the theoretical minimum frequency a human can hear.
An article in Vertical magazine 'The science behind helicopter noise — and how the industry is working to reduce it ' identifies "... two locales where helicopter noise seems to be a major issue. In urban areas, you have a multitude of helicopter operations: law enforcement, medical transport, local news, some business transportation, and tourism. And then there’s the more remote, scenic tourist destinations, where those on the ground object to aircraft interrupting their experience in an otherwise serene wilderness. Typically, helicopter tours are the main source of annoyance in these places.
The majority of this information can be logically applied to what is anticipated from heliport activities on 2224 Tully Mission Beach Road. The Kestral Aviation information sheet states " We will be predominately using our Bell 206L3 Long Ranger and Sikorsky S-76 helicopters, and on rare occasions, our Bell Medium (212 or 412) fleet when need requires (such as in response to natural disasters). Vertical magazine informs "...The Bell 212 generates high levels of impulsive noise..."
The article Dynamics of rock arches shows a plot of the sound spectrum generated by a two-blade Bell 206 helicopter (below). In it you see the first frequency peak at 13 Hz with a series of overtones at integer multiples
Thank you to Margaret Moorhouse from ASH for sharing this information.
This website is managed by Mission Beach Cassowaries inc to share information about the No Helicopters Here campaign against the approval of A HELICOPTER BASE on 2224 Tully Mission Beach Road.
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On 3rd Dec the appeal was reviewed. Judge Morzone ordered (above) the appellant (C4) to provide a list of matters they wish to be considered for inclusion in the proposed conditions attached to any approval of the development application.
On the 3rd September an Order (above) was made by his Honour Judge Morzone QC.
The appeal will be reviewed on 3 December 2021
On the 6th August the court ordered MH to respond to C4 correspondence by August 15th.
Next appeal review is listed for 3rd September.
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