Date:	Saturday 15 March 2025
Time:	11:42 UTC
Type:	Westland Wasp HAS.1
Owner/operator:	Dragonfly Aviation
Registration:	G-CMBE
MSN:	F.9664
Fatalities:	Fatalities: 0 / Occupants: 2
Other fatalities:	0
Aircraft damage:	Substantial
Category:	Accident
Location:	Marston Doles, 4 miles NE of Southam, Warwickshire -   United Kingdom
Phase:	Standing
Nature:	Training
Departure airport:	Marston Doles, Southam, Warwickshire
Destination airport:
Investigating agency:	AAIB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
AAIB investigation to Westland Wasp HAS1, G-CMBE: Loss of control during pre-flight checks, Marston Doles, Warwickshire, 15 March 2025. The incident was the subject of an AAIB Investigation, published on 14 August 2025, and the following is an excerpt from the AAIB Report:

"Synopsis
An instructor and student pilot were carrying out pre-flight checks. One of the checks required the deselection of the hydraulic system to ensure mechanical flying control continuity and freedom of operation in the correct sense. As the instructor selected the hydraulic system off, the collective lever ‘jumped’ upwards and the aircraft lifted into the air. The instructor was unable to regain control and the helicopter struck the ground and rolled over. The cause of the abnormal collective movement could not be positively determined but a transient
system malfunction could not be ruled out.

History of the flight
An instructor was preparing for a routine instructional type rating flight with an experienced rotary wing pilot. They were running through the post engine start pre-flight checks with the rotors running. One of these checks required the hydraulic system to be cycled off, to carry out an assessment of the flight control forces without hydraulic servo assistance. When completed the hydraulic system is selected back on for flight. Immediately the instructor selected hydraulics off, the collective lever forcefully lifted taking the instructor by surprise

The helicopter became airborne to a height of 5 or 6 ft and ”lurched” forward and to the right towards a nearby hangar door. The instructor was unable to select the hydraulic system back on but immediately attempted to regain control. The helicopter moved back away from the hangar and tipped rearwards causing the tail rotor to contact the ground. As this happened the main rotor hit the ground and the helicopter rolled onto its side. The instructor then shut down the engine and made the aircraft safe, after which he extricated himself and assisted the student to vacate the cockpit. The helicopter sustained severe main, tail rotor and structural damage during the accident

Damage Sustained to airframe
Per the AAIB Report "Aircraft fuselage, main and tail rotor impact damage"

1. AAIB Final Report 14 August 2025: https://assets.publishing.service.gov.uk/media/688b4111a509761441437efb/Westland_Wasp_HAS1_G-CMBE_08-25.pdf
2. https://taproot.com/lessons-learned-transient-system-malfunction/
3. Flight Radar 24: https://www.flightradar24.com/data/aircraft/g-cmbe
4. https://www.pprune.org/rotorheads/667712-aaib-h-uk-august-2025-a.html
5. https://airport-data.com/aircraft/NZ3909.html
6. https://airport-data.com/aircraft/G-KANZ.html
7. https://airport-data.com/aircraft/G-CMBE.html
8. https://www.airhistory.net/photo/614506/G-CMBE/NZ3909
9. Photo: https://www.facebook.com/groups/688777827839564/posts/7025337247516892/
10. https://www.helis.com/database/cn/93/
11. https://en.wikipedia.org/wiki/Southam
12. https://en.wikipedia.org/wiki/Napton_on_the_Hill

G-CMBE was built in 1966, and initially delivered 14 October 1966 as XT782 with the Royal Navy. Known Royal Navy service: 829 NAS HMS Euryalus Flt/\\'433\\' by May 1976, until c May 1977. 829 NAS HMS Naiad Flt/\\'324\\' by June 1979, until c. April 1987. Damaged in heavy landing 6 June 1983 when \\'top hat section\\' lifted: repaired
(Was due for delivery to SAAF as \"97\" but not delivered).

To the Royal New Zealand Navy as NZ3909. (Rebuilt by Royal New Zealand Navy as a composite airframe, with major part from Wasps NZ3901 and NZ3904). Withdrawn from Royal New Zealand Navy use April 1997 and sold to Westland Helicopters. It was first civilian registered in the UK as G-KANZ from 21 December 2005, being re-registered as G-CMBE on 17 April 2019.

Marston Doles is a small hamlet in Warwickshire, England, located near the Oxford Canal. It is situated about 4 miles northeast of Southam and is part of the civil parish of Napton-on-the-Hill.

Date/time	Contributor	Updates
22-Aug-2025 16:14	Dr. John Smith	Added
22-Aug-2025 16:16	ASN	Updated [Operator, Narrative, Accident report, ]
29-Sep-2025 09:23	Dr. John Smith	Updated [Registration, ]