Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
CE-09-22
March 30, 2009
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin informs you, an owner
or operator of a Schempp-Hirth model Janus C sailplane (S/N 87 through
252 inclusive) or a Janus CT (S/N 1 through 6 inclusive) powered
sailplane, of an airworthiness concern.
Background
Schempp-Hirth Modification Bulletin No. 809-18 (for Janus CT) and
Technical Note No. 295-25 (for Janus C), previously published in 1992
and 1994 respectively, optionally introduced an enlarged fin/rudder
unit and/or a stiffer horizontal stabilizer. In 1999, the German
airworthiness authority, Luftfahrt-Bundesamt, issued Airworthiness
Directive (AD) number 1999-265 to address a flutter condition on these
enlarged elevator/rudder units and require the installation of heavier
elevator balance weights. However, the announcements issued by
Schempp-Hirth did not incorporate the new balance weights as required
by the LBA AD. As a result, some sailplanes or powered sailplanes
modified after the LBA AD can have inconsistent maintenance data and
have unintentionally reverted to the older and lighter elevator balance
weights.
The European Aviation Safety Agency (EASA) has issued Airworthiness
Directive No. 2009-0054, dated March 6, 2009. This AD requires an
update to the maintenance data and a check of the hinge moments and
balancing weights of the elevator and rudder surfaces. This AD only
applies to serial numbers that have been modified with an enlarged
fin/rudder unit and not equipped with a stiffer horizontal stabilizer.
Sailplanes equipped with the original smaller fin/rudder unit are not
affected.
The EASA AD corrects the inconsistency and the possibility for improper
hinge moments and elevator/rudder balance weights identified above in
the LBA AD.
Recommendations
These sailplanes are not type certificated in the United States and,
therefore, the condition is not addressed by FAA AD action. However,
these sailplanes could be operating in the United States with an
experimental airworthiness certificate or other means. We recommend all
owners and operators comply with actions outlined in EASA AD 2009-0054.