ASN Wikibase Occurrence # 168251
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| Date: | Saturday 17 June 2000 |
| Time: | 08:33 LT |
| Type: |  Agusta A109E Power |
| Owner/operator: | Thames Valley & Chiltern Air Ambulance |
| Registration: | G-TVAA |
| MSN: | 11052 |
| Year of manufacture: | 1998 |
| Engine model: | Pratt & Whitney 206C |
| Fatalities: | Fatalities: 0 / Occupants: 3 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Arborfield Cross, Berkshire -
 United Kingdom
|
| Phase: | Approach |
| Nature: | Ambulance |
| Departure airport: | White Waltham (EGLM) |
| Landing site near Arborfield Cross | |
| Investigating agency: | AAIB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The helicopter was positioning from White Waltham to Arborfield Cross to collect a patient. On arrival the pilot began a 'gentle' right turn at about 300 feet agl at a speed of between 60 and 80 knots in preparation for landing. During this manoeuvre, the occupants heard a loud bang, which appeared to come from the upper rear of the passenger cabin, and the helicopter suddenly 'sank.'
The pilot carried out an auto-rotation but the helicopter touched down hard, collapsing its undercarriage. It then bounced forward but came to rest upright.
The subsequent investigation determined that the loss of control resulted from a fracture of the swash plate scissors link attachment bolt. A short time before the accident flight (3 hours 10 minutes flying time) , the scissors link had been incorrectly assembled and installed with the link positioned back to front.
The design of the scissors linkage is unique to the A109E Power. The lower link on earlier versions of the helicopter is asymmetric in planform and cannot be installed incorrectly. The diagram in the Maintenance Manual did not show the lower link in sufficient detail to allow engineers to correctly orientate the component, and there was no written guidance as to the correct orientation of the link. Additionally, the Part and Batch numbers on other versions of the Agusta 109 are embossed on the inboard side of the link, whereas the equivalent numbers appear on the outboard side of the 109E link.
See also the accidents involving G-JRSL 14 January 2000 and EC-GQX 26 July 1999.
Sources:
1. AAIB: Accident to G-JRSL https://www.gov.uk/aaib-reports/agusta-a109e-g-jrsl-14-january-2000
2. AAIB: Accident to G-TVAA https://www.gov.uk/aaib-reports/agusta-a109e-power-g-tvaa-17-june-2000
3. CAA: https://siteapps.caa.co.uk/g-info/rk=TVAA
4. http://www.ukemergencyaviation.co.uk/G-TVAA.htm
5. http://www.griffin-helicopters.co.uk/accidentdetails.aspx?accidentkey=49
6. https://www.pprune.org/rotorheads/142459-agusta-a109-14.html
7. https://www.helis.com/database/cn/20318/
8. EC-GQX report: http://www.fomento.es/nr/rdonlyres/e8c27c2e-f3cf-4b58-aa8a-266bf2b0e7d7/2438/1999_040_a_eng.pdf
Accident investigation:
 |
|
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 04-Aug-2014 17:49 | Aerossurance | Added |
| 05-Nov-2014 20:56 | Dr. John Smith | Updated [Departure airport, Source, Embed code] |
| 09-Jul-2016 19:43 | Dr.John Smith | Updated [Time, Source, Narrative] |
| 09-Jul-2016 19:46 | Dr.John Smith | Updated [Operator] |
| 23-Sep-2016 08:00 | Aerossurance | Updated [Time, Departure airport, Source, Narrative] |
| 23-Sep-2016 08:07 | Aerossurance | Updated [Source, Narrative] |
Corrections or additions? ... Edit this accident description
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