Date:	Thursday 28 April 2016
Time:	18:03
Type:	Diamond DA42 TwinStar
Owner/operator:	CTC Aviation Group
Registration:	G-CTCB
MSN:	42.083
Year of manufacture:	2006
Fatalities:	Fatalities: 0 / Occupants: 3
Aircraft damage:	Substantial
Category:	Accident
Location:	Bournemouth Airport, Hurn, Bournemouth, Dorset -   United Kingdom
Phase:	Landing
Nature:	Training
Departure airport:	Bournemouth International Airport (BOH/EGHH)
Destination airport:	Bournemouth International Airport (BOH/EGHH)
Investigating agency:	AAIB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
AAIB investigation to Diamond DA42 Twin Star, G-CTCB: Substantially damaged when left main landing gear partially collapsed after landing, Bournemouth Airport, Dorset, 28 April 2016. The incident was the subject of an AAIB Investigation, and the following is an extract from the AAIB Report:

"The accident occurred after landing at the end of a training flight. The student pilot was in control in the left seat and the instructor (commander) was in the right seat. Another student pilot was sitting in the back. The approach to Runway 26 was a practice asymmetric power approach with the left engine set to zero thrust (about 18% power). The wind was from 230° at 15 kt, providing a crosswind of 7.5 kt from the left.

The instructor reported that the approach was stable and the speed well controlled by the student. A few feet before touchdown the student closed both power levers and corrected the drift using the rudder pedals. At touchdown the drift was almost fully corrected and the aircraft aligned with the runway. The instructor reported that the touchdown felt firm but not hard. The deceleration was normal and the aircraft maintained the runway centreline.

At touchdown they heard a continuous beeping noise which they initially thought was the stall warner but then identified as the gear ‘unsafe’ warner. The left main gear green light was off and the red ‘unsafe’ light was flashing. The instructor took control and, after reaching a safe speed, vacated the runway by the nearest taxiway.

The aircraft was still controllable but with increasing difficulty. He stopped the aircraft on the side of the taxiway and shut down the engines in order to inspect the landing gear. After noticing that the left main landing gear had partially collapsed; he asked the student pilot and student passenger to vacate the aircraft carefully.

=Previous DA42 history of failures of the landing gear drag brace rib=
The DA42 type has suffered a number of failures of the landing gear drag brace rib which were attributed to improper bonding of the rib to the centre wing section. This resulted in the aircraft manufacturer publishing a Mandatory Service Bulletin (MSB-42-031/1) in 2007 to perform an inspection of the bonding and carry out a repair if the bonding was inadequate. According to G-CTCB’s airframe logbook this MSB had been carried out on 13 February 2007 and, according to the aircraft manufacturer, there was physical evidence that the MSB repair had been carried out correctly

The aircraft manufacturer reported that since the MSB was issued they have received 11 reports of failures of the main landing gear drag brace rib. They determined that in four of these cases the MSB had not been carried out correctly and one was caused by a storm spinning the aircraft around while parked. The remaining cases were attributed to overload events"

=Damage sustained to airframe=
Per the above AAIB Report damage sustained was "Failure of left landing gear drag brace rib". The aircraft was repaired and returned to service

1. AAIB Final Report: https://assets.publishing.service.gov.uk/media/5849673bed915d0b12000069/Diamond_DA42_Twin_Star_G-CTCB_01-17.pdf
2. https://www.airport-data.com/aircraft/G-CTCB.html
3. https://www.radarbox.com/data/registration/g-ctcb
4. https://www.flightradar24.com/data/aircraft/g-ctcb
5. https://en.wikipedia.org/wiki/Bournemouth_Airport#1990s%E2%80%932000s

This Diamond DA42 TwinStar was built in 2005, and first UK registered (from new) as G-CDTG on 6 February 2006 to Diamond Aircraft UK Ltd (the manufacturers\\\' UK agents). After a further three owners between 2 June 2006 and 9 July 2013, the aircraft was re-registered as G-CTCB on 9 July 2013.

Following the incident at Bournemouth Airport on 28 April 2016, G-CTCB was repaired and returned to service, being sold on to a new (and the current) owner on 12 May 2017. As at 30 May 2023, G-CTCB has accumulated a total of 6,807 flying hours on the airframe.

Date/time	Contributor	Updates
03-May-2024 17:14	Dr. John Smith	Added
03-May-2024 17:14	ASN	Updated [Accident report]