LET Blanik L-13 OE-0935 History Details?

Update on Blanik ADs and Manfacturer Bulletins
8-31-2010

The continuing airworthiness issues, manufacturer’s (LET / Aircraft
Industries) Mandatory Bulletins, European Aviation Safety Administration
(EASA) Airworthiness Directives and the Federal Aviation Administration
(FAA) ADs concern SSA as well as the owners and operators of the affected
L-13 and L-13A Blaniks. It is likely that most of the Blanik fleet in the
United States and around the world will be affected and/or grounded before
the manufacturer and the European agencies issue appropriate methods to
inspect and modify the aircraft to prevent recurrence of the problems that
have led to structural failure and death. The SSA has worked with FAA
since the beginning of the current spar problems.

At this point the manufacturer and EASA have not developed or approved an
effective inspection or modification program to ensure safe continued
flight of the affected aircraft.

However, the FAA’s latest AD states that the flight-hour record-keeping
requirements of the manufacturer do not apply to American operators and
that the FAA will review Alternative Methods of Compliance (AMOC’s)
presented to them. These statements are encouraging for American
operators.

SSA does not have the expertise to engineer solutions, but some of our
members may. SSA encourages qualified members who work on aircraft
inspection and repair methods to contact Greg Davison, Aerospace Engineer
at FAA’s Small Airplane Directorate in Kansas City at (816) 329-4130.
Also please send copies of correspondence with the FAA to SSA and we will
summarize and publish information about them on this site on a regular
basis.

SSA will also use this page to publish other written reports of
developments or offers of assistance. In particular, FAA is working on an
informational statement that it hopes to forward to SSA for publication
in the next few days. At the moment SSA believes that acting as an
information clearinghouse is its most appropriate course of action while
it encourages its members and the owners/operators of Blaniks to work
together to develop technical solutions.

Finally, SSA also believes that owners and operators of affected Blaniks
should make the manufacturer (LET / Aircraft Industries) and its American
representative (Blanik America) aware of their concerns and the need for
their help and timely solutions. Meanwhile, owners with valid questions
and suggestions continue to be invited to contact the FAA as stated in
the AD’s.

SSA Aircraft Certification Committee

Posted: 8/31/2010 By: Government Liaison Committee

Many years (and brain cells) ago I recall looking at an old L-13
spar end cap and it had a very large number of bolts going through
it. It seemed like it was very close to what I remember as a hole
to edge and hole to hole distance requirement. My calibrated
thumb nail showed it to be within what I remember as a 2D
distance but I remember that from rivet holes to edge on wing
skins. I wonder if some of this is caused by hole to hole to edge or
radius cracks and if so that would be a very serious concern. Also,
I believe that the 2D used to be 1.5D and there had been questions
if that was hole edge to edge or hole center to edge.