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ASN Wikibase Occurrence # 189155
Last updated: 31 October 2019
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Date:08-AUG-2016
Time:14:04
Type:Silhouette image of generic BK17 model; specific model in this crash may look slightly different
Kawasaki BK 117C-2
Owner/operator:Aero Asahi Corporation (AKF)
Registration: JA6917
C/n / msn: 4006
Fatalities:Fatalities: 0 / Occupants: 5
Other fatalities:0
Aircraft damage: Substantial
Category:Accident
Location:Hirasawa, Hadano city, Kanagawa prefecture -   Japan
Phase: Landing
Nature:Ambulance
Departure airport:Temporary Operation Site, Isehara city, Kanagawa prefecture
Destination airport:Hirasawa, Hadano city, Kanagawa prefecture
Investigating agency: JTSB
Narrative:
An ambulance helicopter with a medical doctor on board, Kawasaki BK117C2, crash landed at Hirasawa, Hadano city, Kanagawa prefecture, Japan. The medical helicopter contacted its tail on the ground during the hovering just prior landing to pick up an injured high school boy by a traffic accident. The tail section was separated from the fuselage. Five occupants on board were not injured. The patient to be picked up was sent to a hospital by a conventional ground ambulance with applying initial treatments by the medical crew of the accident helicopter, however, he was dead. The helicopter was operated by Aero Asahi Corporation (ICAO code AKF) for Tokai University Hospital.
On 17th August, Tokay University Hospital announced that there was a meeting by the related agencies on the accident on 12th August, and it had suggested in the meeting that some complex wind changes induced by the severe tropical storm STS1605 OMAIS (1605) located at about 450km east, might be a factor of the accident.

The weather data at Atsugi Airbase (RJTA: about 24km ENE of the accident site):
RJTA 080500Z 01023KT 9999 SCT020 BKN230 33/22 Q1000 RMK 3CU020 A2955 PEAK GUST 31KT=
(05:00 UTC/14:00 JST, wind 010 degrees at 23 knots, peak gust 31 knots, visibility 10km+, clouds 3 oktas cumulus 2000 feet and broken 23000 feet, temperature 33 degree-Celsius, dew-point 22 degree-Celsius, QNH 1000 hPa, 29.55 INS)

PROBABLE CAUSES
It is highly probable that in this accident, the rotorcraft was damaged because the landing was resulted in the hard landing. With regard to the hard landing of the rotorcraft, it is probable that because it did not used an approach path to the temporary helipad along an approach surface which is confirmed to comply with the standard, flew over the high steel tower near the temporary helipad of the planned destination, commenced the approach at a rather large approach angle and descent rate, and decreased the forward airspeed in order to transit to hover, the main rotor developed VRS and in spite that the pilot pulled CP up, the corresponding lift could not be gained.

Sources:

https://www.aeroasahi.co.jp/news/detail.php?id=66
[LINK NOT WORKING ANYMORE:http://www3.nhk.or.jp/lnews/yokohama/1056986471.html?t=1470665625750]
https://headlines.yahoo.co.jp:443/hl?a=20160808-00000064-asahi-soci
http://www.j-hangarspace.jp/wp-content/uploads/2013/05/JA6917.jpg
http://jtsb.mlit.go.jp/jtsb/aircraft/detail2.php?id=2162
https://headlines.yahoo.co.jp:443/hl?a=20160817-00010001-tvkv-soci

Accident investigation:
cover
  
Investigating agency: JTSB
Status: Investigation completed
Duration: 1 year and 4 months
Download report: Final report


Revision history:

Date/timeContributorUpdates
08-Aug-2016 16:19 isamuel Added
08-Aug-2016 18:12 Geno Updated [Source]
08-Aug-2016 19:56 TB Updated [Time, Aircraft type]
09-Aug-2016 07:35 isamuel Updated [Departure airport, Destination airport, Source, Narrative]
17-Aug-2016 14:09 isamuel Updated [Source, Narrative]
07-Dec-2017 18:20 harro Updated [Narrative]

Corrections or additions? ... Edit this accident description