Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
CE-09-45
July 29, 2009
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) advises you,
owners and operators of Viking Air Limited DHC-2 MKI, of an
airworthiness concern, specifically the importance of implementing the
recommendations provided in Viking Air Limited Service Letter
DHC2-SL-01-001, Issue 1, dated April 24, 2008.
At this time, this airworthiness concern is not considered an unsafe
condition that would warrant an airworthiness directive (AD) action
under Title 14 of the Code of Federal Regulations (14 CFR part 39).
Background
There have been several reports of DHC-2 MKI aircraft modified to
Supplemental Type Certificate (STC) SA00299NY without the installation
of a ventral fin (Kit VALBVS1266-1), which is a requirement of the STC.
The purpose of this SAIB is to emphasize that a ventral fin and Kenmore
Auxiliary Fins (STC SA456NW) are required on the DHC-2 MKI aircraft
modified to STC SA00299NY.
The discrepancy was
introduced at revision 4 of Installation Instructions VALBVS1256-27 in
Table 3.3, which listed the ventral fin installation kit VAL BVS1266-1
as optional.
Earlier revisions to
Installation Instructions VALBVS1256-27 were approved either by the FAA
through the issuance of STC SA00299NY or by Transport Canada, the state
of design of the DHC-2 aircraft.
Revision 4 of Installation
Instructions VALBVS1256-27, however, was neither approved by the FAA
nor Transport Canada. This unapproved Installation Instructions
VALBVS1256-27 at revision 4 was inadvertently obtained and used by some
DHC-2 owners and operators, who interpreted the installation of a
ventral fin as optional.
Revision 4 of Installation
Instructions VALBVS1256-27 contradicts the top drawing VAL BVS 1256 as
referenced in STC SA00299NY which clearly states that the ventral fin
is required for the DHC-2 MKI aircraft fitted with EDO 679-4930 or
58-4580 floats.
Service Letter
DHC2-SL-01-001 was issued by Viking Air Limited to communicate this
discrepancy that exists between the top drawing VAL BVS 1256 referenced
in STC SA00299NY and the Installation Instructions VALBVS1256-27.
Viking Air Limited has
revised Installation Instructions VALBVS1256-27 at revision 6, dated
June 10, 2008, Transport Canada approved July 11, 2008, which removed
the word “optional” to bring it into alignment with top drawing VAL BVS
1256 and to reduce the possibility of non-conforming configuration in
future installations.
Viking Air Limited will distribute Installation Instructions VALBVS1256-27 at revision 6 to all applicable operators shortly.
Recommendations
We recommend that you implement the recommendations provided in Viking
Air Limited Service Letter DHC2-SL-01-001 and to attach this Service
Letter to your current STC Installation Instructions Manual for
reference if you have not received revision 6 of Installation
Instructions VALBVS1256-27.
If you have received revision 6 of Installation Instructions
VALBVS1256-27, we recommend that you use this revision in place of all
previous revisions.
We also stress the importance of adherence to the approved aircraft
configurations by the installer and the importance of following
operating procedures by pilots and operators.
For Further Information Contact
Pong K. Lee, Aerospace Engineer
FAA, Engine & Propeller Directorate
NYACO, ANE-171
1600 Stewart Avenue, Suite 410
Westbury, NY 11590
phone: (516) 228-7324
fax: (516) 794-5531
email: pong.k.lee@faa.gov