Accident Agusta A109E Power G-TVAA,
ASN logo
ASN Wikibase Occurrence # 168251
This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information. If you feel this information is incomplete or incorrect, you can submit corrected information.

Date:Saturday 17 June 2000
Time:08:33 LT
Type:Silhouette image of generic A109 model; specific model in this crash may look slightly different    
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
Location:Arborfield Cross, Berkshire -   United Kingdom
Phase: Approach
Departure airport:White Waltham (EGLM)
Destination airport: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.


1. AAIB: Accident to G-JRSL
2. AAIB: Accident to G-TVAA
3. CAA:
8. EC-GQX report:

Accident investigation:
Investigating agency: AAIB
Report number: 
Status: Investigation completed
Download report: Final report

Revision history:

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

The Aviation Safety Network is an exclusive service provided by:
Quick Links:

CONNECT WITH US: FSF on social media FSF Facebook FSF Twitter FSF Youtube FSF LinkedIn FSF Instagram

©2023 Flight Safety Foundation

1920 Ballenger Av, 4th Fl.
Alexandria, Virginia 22314