Date:	Thursday 27 July 2017
Time:	13:55 LT
Type:	Airplane Factory Sling 4
Owner/operator:	Private
Registration:	G-LDSA
MSN:	LAA 400-15412
Fatalities:	Fatalities: 0 / Occupants: 2
Other fatalities:	0
Aircraft damage:	Minor
Category:	Serious incident
Location:	near Hailsham, East Sussex -   United Kingdom
Phase:	En route
Nature:	Private
Departure airport:	Lydd International Airport (LYX/EGMD)
Destination airport:	Shoreham Airport (ESH/EGKA)
Investigating agency:	AAIB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
AAIB investigation to Airplane Factory Sling 4, G-LDSA: Minor damage when canopy door detached in flight, near Hailsham, East Sussex, 27 July 2017. The incident was the subject of an AAIB Investigation, and the following is an excerpt from the AAIB Report:

"The aircraft’s owner, who was piloting the aircraft, and a passenger who was also a pilot, were flying from Lydd Airport to Shoreham Airport. The pilot was in the front left seat and the passenger was seated next to him. About 30 minutes into the flight, at an altitude of 2,200 ft and airspeed of about 116 kt, there was a sudden increase in wind noise in the cockpit accompanied by the passenger feeling a “blast of air on his face”.

The passenger then noticed that the right canopy door had opened about 5 cm at its upper forward corner, with the gap tapering back to the rear of the canopy. After about 15 to 20 seconds, there was a loud bang and the canopy departed the aircraft. The pilot informed ATC at Shoreham, where the aircraft subsequently landed without further incident. Sussex Police were also notified. The canopy door has not been located to date and no injuries to persons or damage to property on the ground have been reported.

The LAA inspected the aircraft and contacted the aircraft manufacturer. Analysis of damage to the forward and aft hinge fuselage attachment points indicate that both hinges failed in overload. Both forward and aft latch pins remained attached to the fuselage and were both intact. The canopy was not recovered and so it was not possible for the canopy locking lever and mechanism to be examined.

The pilot stated that the passenger had advised him that the lever had remained in the closed position until the canopy detached from the aircraft. However, the LAA found that it was possible to partially lock the canopy with the lever not fully in the closed ‘over-centre’ position.

There have been no other reported incidents for this aircraft type of a canopy opening in flight. The LAA is to publish a safety article reminding pilots to check that canopies are fully locked prior to flight.

=AAIB Conclusion=
The inspection of the aircraft by the LAA indicates that the canopy opened in flight because the passenger door lever was not in the fully closed position. It is possible that the lever may not have been in the fully closed position prior to the commencement of the flight, or that the lever was inadvertently moved at some point during the flight.

=Damage sustained to airframe=
Per the above AAIB Report "Right canopy door detached in flight". A new right canopy door was fitted, and the aircraft returned to service

1. AAIB Report: https://assets.publishing.service.gov.uk/media/5a0ac078ed915d0adcdf4729/Sling_4_G-LDSA_12-17.pdf
2. https://www.airport-data.com/aircraft/G-LDSA.html
3. https://en.wikipedia.org/wiki/Sling_Aircraft_Sling_4
4. https://en.wikipedia.org/wiki/Hailsham

This Airplane Factory Sling 4 was built in 2017, and was first registered (in advance, while under construction) as G-LDSA on 6 July 2016, to the airframes one-and-only owner to date.

After the incident near Hailsham on 27 July 2017, a new right canopy door was fitted, and the aircraft returned to service. As at 18 April 2024, G-LDSA had accumulated a total of 288 flying hours on the airframe

G-LDSA: Airplane Factory Sling 4 at the LAA Rally, Sywell, Northamptonshire (ORM/EGBK) 1 September 2017

Date/time	Contributor	Updates
04-Jun-2024 13:51	Dr. John Smith	Added
04-Jun-2024 13:51	ASN	Updated [Accident report]
06-Jun-2024 17:33	Dr. John Smith	Updated [Narrative]