We bought a Jodel DR1050 in December1999. We knew it was built from 2 crashed aircraft in the 70s. When the wing showed a glue problem in January 2017, it was removed and fabric stripped. A few rib bits needed re-glueing. The mainspar was seen to have been broken and repaired – properly, with no resulting problems.
I had flown 1,000 hours in her when she was delivered for new owner, by me in December 2020.
The DR1050 wing is similar to the Robin. DR Delanontes Robin)
Legend: Many years ago a Robin was found to have a badly glued mainspar after a fatal crash for an unrelated cause. Robin claimed the spar met specification. To prove this they built an identical spar. It went far above the needed force before it broke. (15g??)
For those of you who have not seen inside a Robin wing I offer this photo.
The Delanontes mainspar (yellow) is a box, with internal wood crossing pieces. Homebuilders have to leave top off until inspected.
I wonder what mistake Robin made with the spars. Wood quality?
Replacing internal fittings looks like it might be a major job.
Maoraigh
I very much doubt this is a problem with the quality of the wood, last time they had spar issues it was a problem with the techniques used when applying the glue.
The glue used is a what was once marketed as Aerodux it is a resorcinol resin type glue with a limited working time once mixed.
The problem with the glue comes when building large structures as the glue should be applied to both components and then clamped in place to set. If the job is left open for too long the glue starts to set from the outside and forms a semi flexible skin. In this state the glue joint can still be clamped but the skin on both sides of the glue joint will not bond properly and full strength is not achieved.
I am told that the last time Robin had problems with spar’s that it was when they tried to glue the whole spar at once to speed production, this resulted in doubts about the glue strength and an AD issued to fit additional parts inside the spar to assure enough glued area to maintain structural integrity.
While I have no inside information this looks like a quality control issue that has come from a change in production techniques, the Robin SB states that within three weeks they will have a plan to fix the problem and a one flight authorisation will be granted to get the aircraft to the factory.
I am sure more facts will emerge as time passes but I will issue the health warning that all I have written is no more than my best guess.
If they used “wrong or wrongly mixed glue” then this is not doable with just a patch.
It’s not that different to the Socata corroding wing spar issue.
For anyone interested in the topic a further explanatory SB revision has been issued.1678127369_221201R2_IMPERATIF_COLLAGE_LONGERON_pdf
Paul.
Repairs are affected since 1974? Wow.
How sad, possible law suits following the disaster of failed industrial production at small quantities forced the company to declare bankruptcy? So, all the owners will now sit on possibly 5?-figures repair costs without any chance to get any compensation? That is a way to wreck the reputation of one of the last serious GA aircraft manufacturer in Europe … sad, sad, sad.
They will have had product liability insurance, but that covers only production up to present time.
If trading from that point on is problematic, you have to review what you want to do.
Apparently the airplanes concerned are no longer grounded, but subject to flight limitations.
10. LIMITATIONS
Before the next flight, the aircraft identified in §1 must be operated within the following limitations:
a) All flight manoeuvres shall be executed with care and only by smooth action on the flight controls;
b) Turns with more than 60° bank (inclination), lazy eights, chandelles, and any other aerobatic manoeuvres are prohibited;
c) VNO is reduced to 230 km/h (124 Kts);
d) Intentional stalls are allowed, provided performed with an instructor on board who has direct access to the flight controls, to ensure that the above limitations are not exceeded.
The question is, can this condition be rectified and how? They are talking of a service bulletin or procedure which, if it has been applied, removes the airplane from the affected list. So could this be applied to affected airframes?
