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ASN Wikibase Occurrence # 246800
Last updated: 16 September 2021
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Time:14:15 UTC
Type:Wingcopter 178 Heavylift
Registration: Unregistered
MSN: SN-0084
Fatalities:Fatalities: 0 / Occupants: 0
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:Mayfield Farm, Ilsley Road, Compton, Newbury, West Berkshire -   United Kingdom
Phase: En route
Departure airport:Mayfield Farm, Ilsley Road, Compton, Newbury
Destination airport:Mayfield Farm, Ilsley Road, Compton, Newbury
Investigating agency: AAIB
AAIB investigation to Wingcopter 178 Heavylift, UAS, registration n/a: Loss of control due to ESC overheating, Mayfield Farm, Ilsley Road, Compton, Newbury, West Berkshire, RG20 7BR, 4 September 2020. The AAIB Final Report was published 15 January 2021, and the following is an excerpt from it...

"The Wingcopter 178 Heavylift, (Figure 1) is an unmanned electric Vertical Takeoff and Landing (eVTOL) aircraft with a maximum takeoff weight of 18 kg. It can take off and land vertically like many multirotor unmanned aircraft but can transition to wing-borne flight by rotating its two forward propellers to a horizontal position and folding its rear propellers to reduce drag. In ‘fixed wing mode’ the aircraft is capable of ranges of up to 75 miles and speeds up to 150 mph, dependent on payload. The aircraft has a 1.78 m wingspan and is 1.32 m long.

The UA was conducting a test flight to verify its performance at its maximum takeoff mass (MTOM), using an automated mission profile that it had successfully completed five times before.

After conducting the pre-flight and mission checks the remote pilot (RP) armed the aircraft, confirmed that the motors had spooled up correctly and initiated the automatic flight by switching the radio control transmitter to ‘mission’ mode. The aircraft lifted off successfully and began to climb in ‘hover mode’ towards its target height of 110 m agl at which point the aircraft would transition to ‘fixed wing mode’.

Recorded data from the aircraft shows that it initially climbed vertically to approximately 35 metres agl before continuing a programmed translational climb in ‘hover mode’ to the south west. After 72 seconds, whilst approaching 100 m agl, and having travelled 188 metres, the aircraft rolled and pitched to the right and became temporarily inverted. It righted itself, but was unable to maintain control, descending rapidly whilst spinning in a clockwise direction. The RP reported that it was evident that one of the motors had lost propulsion. He attempted to gain control of the aircraft by switching to manual control, but this was unsuccessful.

As the aircraft descended some thrust was still produced by the operating motors prolonging the descent. The UA travelled approximately 80 m downwind before striking the ground in a harvested crop field. There were no injuries, although the aircraft was destroyed.

=Aircraft examination=
Assessment of the aircraft by the operator, in conjunction with the manufacturer, identified that a rear ESC had overheated resulting in the loss of control of its associated motor. This issue had been previously identified by the manufacturer and a hover time limitation of 120 seconds, to prevent the overheating, had been imposed. It is considered that the ESC overheated due to the increased load produced as a result of the combination of the
duration of the translational climb and operation close to MTOM. The manufacturer is currently working on resolving this issue by introducing re-designed rear propellers to the aircraft type.

=Damage to Airframe
Per the AAIB Report above, the UAS was "destroyed"


1. AAIB Final Report:

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


Wingcopter 178 in transition Wingcopter Transition

Revision history:

16-Jan-2021 10:19 harro Added
30-Jun-2021 21:02 Dr. John Smith Updated [Registration, Operator, Location, Source, Narrative, Category]
30-Jun-2021 21:05 Dr. John Smith Updated [Source, Embed code]

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