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Facts about TAKAE > Noise and Low Frequency Noise by Ospreys

Noise and low frequency waves generated by MV22 Osprey severely harms the residents in Takae (this post is a partial translation of 高江ヘリパッド>騒音、低周波のこと).

In No Helipad Residents Society Blog, “How MV22 Ospreys fly in Takae,” , a resident wrote (translated and quoted by Project Disagree)
“In Takae, two or three Ospreys fly in formation, through same path again and again for their training.”
“A 100 dB noise is said to be comparable to a horn of a car, but the noise of an Osprey is heavy bass sound and I feel my internal organs trembled."
“The data proved the noise events at that night, over 80dB happened 28 times in two hours. It means that the roar from the osprey shakes the whole house at night after 9pm, continuing in two hours and longer, at the intervals of  5 to 10 minutes."

Here, summarized from articles of Ryukyu Shimpo, one of the local newspapers in Okinawa, which covered the facts about the noise problems in Takae.

“Takae in June, counted noise events at night up to 383, increasing 24 times more, 8 times per day,” Ryukyu Shimpo July 20, 2016.
●Okinawa Defense Bureau (a national bureau) disclosed the noise data after the Assembly of Okinawa Prefecture claimed it.
●Data of June 2016 in the district of Takae shows increase in comparison with the year 2014.
●Noise apparently intensified after the deployment of Ospreys to US Marine Corps Futenma Air Station in Okinawa.
▶Number of night-time noise events
 383 (June, 2016) > 16.2 (2014 average)
▶Number of night-time noise events per day
 32.8 (June, 2016) > 4.1 (2014 average)
▶Average Lden *
53.8 dB (June, 2016) > 39.5 dB (2014 average)
*Lden = the equivalent continuous noise level over a whole 24-hour period with noise in the evening (19:00 to 23:00) increased by 5 dB(A) and noise at night (23:00 to 07:00) increased by 10 dB(A) to reflect the greater noise-sensitivity of people at those times.

“100 dB noise level when three Ospreys training in formation in Takae,” Ryukyu Shimpo, July 15, 2016.
●Takae residents investigated the noise generated from Osprey training at “N4” helipads with the support of a university expert.
●Sound level instrument was set near two new helipads called “N4,” in the vicinity of Takae residential area and only 300m from the prefectural road.
●Japanese government offered “N4” helipads to US Forces in February 2015 prior to the completion of the whole construction project. USMC used them for multiple Ospreys training in formation.
▶Max 99.3 dB, 80.9 dB/hour (June 20, 2016)
▶Max 96.8 dB, 79.0 dB/20 min (June 21, 2016)
▶Max 93.4 dB, 81.3 dB/5 min (June 23, 2016, prefectural memorial day for the Battle of Okinawa)

“77% ‘annoyed,’ 38% ‘scared of Ospreys,’ in survey of all the children in Higashi Village,” Ryukyu Shimpo, July 15, 2016.
●A university expert conducted a survey among all the pupils and students in Higashi Village.
▶“Noise from Ospreys is scared, feel bad": 38%
▶“I have experiences to be annoyed by noise from helicopters and aircrafts when in school” : 77%
▶“I can tell Ospreys from the other aircrafts by their noise”: 81%
▶“Ospreys are noisier than the other aircrafts” : 82%
▶individual comments:
“It seems to fall down to me and scared.”
“I can’t sleep with the noise.”
“School class is suspended because of the noise.”
“It is scary when they fly low.”
“They fly noisy late at night like 10pm.”
“I feel scared when many aircrafts fly at once.”
“Sometimes I can’t concentrate on a class."

“Takae public school suffers high levels of low frequency noise, affected by the operation of the new helipads,” Ryukyu Shimpo, March 25, 2016.
●In the absence of the public measures for the low frequency noise, Takae residents efforts provided the evidence by the specific data.
▶At the public school in Takae on Dec. 7, 2015 (1.7km from N4 helipads)
92.9 dB at 40Hz (14.9 points higher than the reference level set by the Ministry of Defense)
▶At the private office on February 25, 2015 (450m from N4 helipads)
88.3dB at 20Hz (12.3 points higher than the reference level of mental impact, 8.3 points higher than the reference level of physical impact, both are set by the Ministry of the Environment)