Accident Aerospool WT-9 Dynamic PH-4E7, Saturday 13 February 2021
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Date:Saturday 13 February 2021
Time:c. 15:10
Type:Silhouette image of generic WT9 model; specific model in this crash may look slightly different    
Aerospool WT-9 Dynamic
Owner/operator:Vliegclub Fryslân
Registration: PH-4E7
MSN: DY318/2009
Fatalities:Fatalities: 1 / Occupants: 1
Other fatalities:0
Aircraft damage: Destroyed
Location:Kornhorn, Groningen prv -   Netherlands
Phase: En route
Departure airport:Drachten Airfield (EHDR)
Destination airport:Drachten Airfield (EHDR)
Investigating agency: Dutch Safety Board
Confidence Rating: Accident investigation report completed and information captured
An Aerospool WT-9 Dynamic aircraft crashed near Kornhorn and was partly consumed by fire.
The sole pilot was killed.

The accident:
After the sudden opening of the canopy during flight, the pilot lost control of the aircraft.
Why the pilot lost control could not be determined. Canopy opening caused an upset from which the pilot was likely unable to recover.
It is most likely that the canopy was not properly closed by the pilot before the aircraft took off.
Pre-existent cardiac abnormalities were found with autopsy. A relationship with the cause of the accident cannot be excluded. There are no indications that the loss of control was primary caused by a physical problem of the pilot.
The technical investigation of the aircraft wreckage did not reveal any technical abnormalities that could have been a contributing factor to the cause of the accident.

The canopy:
Operating the latching and locking system of the canopy is sensitive to errors. It might appear that the canopy is closed when this is not the case if insufficient attention is paid to it. The gap between the canopy and the fuselage can be overlooked.
The risk of inadvertent opening of the canopy during flight, which has led to multiple fatal accidents, was known to the aircraft manufacturer. In response, a mandatory service bulletin and a recommendation bulletin were published by the manufacturer. The publication of a mandatory bulletin with operational measures did not prevent taking off when the canopy is not properly closed and locked.
A solution to prevent taking off while the canopy is not properly closed and locked, is available. It is not mandatory to install this provision.
Mandatory and important safety information was not implemented in the Pilot’s Operating Handbook (POH) of PH-4E7. The aircraft was delivered by the representative with a POH that did not include the changes as stated in the mandatory service bulletin.
The mandatory service bulletin was not noticed by the holder for several years.
The Dutch Human Environment and Transport Inspectorate (ILT) does not actually check whether the information as stated in the application form for a Special Certificate of Airworthiness (S-BvL) extension has been filled in truthfully. Therefore the information contained in the mandatory service bulletin on canopy opening failed to reach the pilots.

The flying club:
The maintenance by the flying club of their aircraft was not properly and structurally arranged. Different interpretations of safety practices and an informal atmosphere within the flying club allowed potential dangerous situations to arise. This may have played a role.

MLA regulation and oversight:
The European regulatory framework for aviation safety is not applicable for microlight aircraft (MLA) as they are considered to be a form of aviation with a limited risk. Only national requirements apply.
Oversight by ILT on MLA is virtually non-existent. The approval or extension of a special certificate of airworthiness is only based on the declaration of the holder. However, the mere issuance of such an certificate may give the impression to holders and pilots that an additional check or verification by ILT has been performed while this is not the case; the airworthiness has not been established. Therefore the safety level of MLA aviation depends almost exclusively on the holders and pilots of these MLA.
Despite the Minister’s commitment to evaluate and, if necessary, adjust the oversight of MLA, the oversight program for MLA has not been amended or intensified. Despite the development and increase in MLA flying, it is considered to be a form of aviation with limited risk. Due to the scarcity of resources, no actual oversight of administrative and operational requirements is taking place.

Accident investigation:
Investigating agency: Dutch Safety Board
Report number: 
Status: Investigation completed
Duration: 2 years
Download report: Final report

Sources: (photo)


Revision history:

13-Feb-2021 15:02 RobertMB Added
13-Feb-2021 15:09 RobertMB Updated [Aircraft type, Nature, Source, Damage, Narrative, Plane category]
13-Feb-2021 15:11 Aerossurance Updated [Embed code]
13-Feb-2021 15:19 RobertMB Updated [Registration, Cn, Operator, Source, Embed code]
13-Feb-2021 15:42 Notarhelicopters Updated [Phase, Departure airport, Source]
13-Feb-2021 15:51 RobertMB Updated [Total fatalities, Total occupants, Other fatalities, Departure airport, Destination airport, Source, Narrative]
13-Feb-2021 18:55 harro Updated [Location, Narrative, Category]
20-Jun-2022 00:42 Ron Averes Updated [Location]

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