Thanks very much for your help, guys. Nige, the aero restrictions on SB 12
came in earlier (Jan 1985). The wing failure from a July 1986 accident in
Germany indeed was the result of acc to the investigation high g loading - at
high angles of attack. Wolf Hoffmann further said to Tom awhile back
commenting on this that the LBA wanted them to “do something” even if no
structural imperfection was found, thus the SB 19 winglatch kit. We got the
original accident summary from the BFU database, it doesn't say much, but it
does say this:
Accident in Walchensee on 29.07.1986
Aircraft wing related event (ATA Code:5700) , during Cruise. {Occurrence}
Fuselage main bulkheads (ATA Code:5312)
Wing attachment fitting (ATA Code:5740)
Weather conditions VMC
Aircraft SN 36115 D-KESL
Aircraft total time 820 Hours *flying club
crew experience This Aircraft type 17 Hour(s)
All types 1198 Hour(s)
Events: primary break of the right wing in the flight (SE) - cruising (D1) |_
FUSELAGE/BULKHEADS (70BA) |_ Not
sufficiently firm/solid (88H4) |_ WINGS/WING ATTACHMENT FITTINGS, BOLTS (70AC)
|_ Not sufficiently firm/solid
(88H4)
Sent from Windows Mail
From: ni...@limbachaustralia.com
Sent: Saturday, June 25, 2016 10:41 AM
To: dog@lists.riverland.net.au
Yep. I have had it go in unintentionally a couple of times while soaring in
thermal conditions. A good gust brought it on both times. It is quite benign
and relaxing back stick is enough to get a quick recovery from the start of an
incipient. I have deliberately done it once to see what it is like although
didn’t let it fully develop. Again I would describe it as a bit benign. Easy
recovery and no noticeable hesitation. I did it intentionally with 1 up but the
other 2 times were 2 up. All 3 times were at about half fuel load. It isn’t
what I would say as prone to spinning IE doesn’t drop in at the drop of a hat.
Hope that is of help.
I thought the Aero restrictions came in after the catastrophic wing failure
from Gross Overload during Aero’s and thus SB19.
Cheers.
Nige.
From: Kristin Nowell
Sent: Saturday, June 25, 2016 10:30 AM
To: dog@lists.riverland.net.au
Subject: [DOG mailing list] Spins
Hi all,
Our glider aerobat friend (Unlimited!) is coming to Maine for vacation, and is
keen to fly in Tom's Dimona. Has anyone ever (unintentionally) spun it?
Originally it was certified for aerobatics but then came 1985 SB 12 ( "Due to
irregularities observed at spinning, further tests will be performed and until
then the placard must be installed....), like what kind of irregularities? And
either the tests were not done or not satisfactory as this operating
restriction was never lifted, unlike those of service bulletin 18 ("glider
flying prohibited!" "dual controlled instruction flights only"!), which were
removed upon install of the wing latch kit (SB 19).
Thanks Kristin
