Mid-air collision Accident Guimbal Cabri G-2 G-JAMM,
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ASN Wikibase Occurrence # 201438
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Date:Friday 17 November 2017
Time:12:06 LT
Type:Silhouette image of generic G2CA model; specific model in this crash may look slightly different    
Guimbal Cabri G-2
Owner/operator:Helicopter Services
Registration: G-JAMM
MSN: 1185
Fatalities:Fatalities: 2 / Occupants: 2
Aircraft damage: Written off (damaged beyond repair)
Location:Waddesdon near Aylesbury, Buckinghamshire -   United Kingdom
Phase: En route
Departure airport:Wycombe Air Park (HYC/EGTB)
Destination airport:Wycombe Air Park (HYC/EGTB)
Investigating agency: AAIB
Confidence Rating: Accident investigation report completed and information captured
A Cessna 152 (G-WACG) and a Guimbal Cabri G-2 (G-JAMM) crashed following a mid-air collision near Aylesbury, England. Both occupants of the Cessna and both occupants of the Cabri helicopter, pilot and student, suffered fatal injuries.

The Cessna departed Wycombe at 11:46 on a local training flight to practice 'best rate of climb' and 'glide descent' exercises. The aircraft climbed steadily up to an altitude of 2,000 ft before turning on course to the local training area northwest of the aerodrome. At 11:50 hrs G-WACG confirmed with Wycombe Tower that they had left the circuit area; there were no further radio communications from the aircraft. G-WACG reached 4,000 ft, turned left onto a steady north-westerly course and then commenced a sustained descent which continued until the point of collision. The collision occurred 14 minutes after takeoff from Wycombe.

The Cabri helicopter departed Wycombe at 11:47 on a local navigation exercise. The instructor in G-JAMM advised Wycombe Tower they were leaving the circuit to the north; there were no further radio communications from the helicopter. G-JAMM climbed to and maintained an altitude of around 1,500 ft amsl until the point of the collision.

AAIB Conclusion:
The geometry of the flight paths was such that the opportunity for the occupants of the two aircraft to ‘see and avoid’ each other was very limited. The damage sustained to each aircraft was such that neither could continue in controlled flight.

It is not known whether shallow turns were made during G-WACG’s descent from 4,000 ft and G-JAMM’s main rotor paint scheme would not have enhanced visual conspicuity when viewed from above.

As the separation between the two aircraft gradually reduced over several minutes, the use of compatible EC devices could have improved situational awareness such that avoiding action could be taken.


1. AAIB Final Report: https://assets.publishing.service.gov.uk/media/5bc733dae5274a361ac03dd4/Cessna_152_G-WACG_Guimbal_Cabri_G2_G-JAMM_11-18.pdf
2. https://www.gov.uk/government/news/the-aaib-is-sending-a-team-to-buckinghamshire
3. https://www.telegraph.co.uk/news/2017/11/17/aylesbury-mid-air-crash-fatalities-feared-afteraircraft-helicopter/
4. http://www.bbc.co.uk/news/uk-england-beds-bucks-herts-42024712 (Update)
5. http://www.bbc.com/news/uk-england-beds-bucks-herts-42037839
6. https://www.dailystar.co.uk/news/latest-news/660777/Aylesbury-crash-aircraft-helicopter-mid-air-collision-Buckinghamshire-M40-motorway
7. http://www.dailymail.co.uk/news/article-5093089/Helicopter-plane-crash-mid-air-collision.html
8. https://www.dailyrecord.co.uk/news/uk-world-news/victims-mid-air-helicopter-plane-11548434
9. https://publicapps.caa.co.uk/modalapplication.aspx?catid=1&pagetype=65&appid=1&mode=detailnosummary&fullregmark=JAMM
10. https://www.jetphotos.com/photo/8635782
11. https://www.flightradar24.com/data/aircraft/g-jamm#f8ef99a
12. http://aerossurance.com/helicopters/mac-electronic-conspicuity/
13. G-WACG: https://aviation-safety.net/wikibase/wiki.php?id=201436

Accident investigation:
Investigating agency: AAIB
Report number: 
Status: Investigation completed
Duration: 11 months
Download report: Final report



Revision history:

17-Nov-2017 15:41 Geno Updated [Time, Location, Departure airport]
17-Nov-2017 16:25 Anon. Updated [Aircraft type, Registration, Cn, Source]
17-Nov-2017 16:29 Michael Roots Updated [Aircraft type, Operator, Total fatalities, Total occupants, Other fatalities, Source]
17-Nov-2017 17:06 harro Updated [Aircraft type, Operator, Damage, Narrative]
17-Nov-2017 17:15 Geno Updated [Source]
17-Nov-2017 18:57 Aerossurance Updated [Time, Location]
17-Nov-2017 19:56 Iceman 29 Updated [Embed code]
17-Nov-2017 20:14 Iceman 29 Updated [Source, Embed code, Photo, ]
17-Nov-2017 20:42 Iceman 29 Updated [Other fatalities, Source, Narrative]
18-Nov-2017 12:02 Iceman 29 Updated [Source, Embed code]
19-Nov-2017 19:35 Iceman 29 Updated [Nature, Source, Narrative]
21-Nov-2017 07:58 MarkStep Updated [Source]
21-Nov-2017 08:08 harro Updated [Source]
09-Nov-2018 15:04 harro Updated [Destination airport, Narrative, Accident report, ]
11-Nov-2018 20:39 Dr.John Smith Updated [Source, Narrative]
24-Nov-2018 18:07 Aerossurance Updated [Source]

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