Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
CE-08-01
October 18, 2007
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin informs you of an
airworthiness concern for Grob Models Twin Astir, Twin Astir Trainer,
G103 Twin II, G103A Twin II Acro, G103C Twin III Acro, and G103C Twin
III; all serial numbers.
Background
Grob received a report that a spar stub failed in flight on a G103C
Twin III Acro. Extensive investigations were performed at independent
places, but a root cause could not be clearly identified. Damage
potentially caused by a hard landing, ground loop, an exceeding of
permitted speed limits or maneuvering factors, or an inappropriate
repair could not be excluded.
The European Aviation Safety Agency (EASA) has issued Emergency
Airworthiness Directive No. 2007-0194-E, dated July 30, 2007, for those
sailplanes registered for operation in Europe. That AD is based on Grob
Service Bulletin MSB-74/1 and MSB 869-25/1, dated July 30, 2007.
Since the airworthiness concern can not be specifically determined nor
can the condition be proven to exist or develop on other products of
the same type design, airworthiness directive action by the FAA is not
warranted under Title 14 of the Code of Federal Aviation Regulations
(14 CFR) part 39.
Recommendations
In the manner of safety awareness, we recommend all owners and
operators comply with actions outlined in Grob Service Bulletin
MSB-74/1 and MSB 869-25/1.