Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
NE-09-04
January 12, 2009
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) alerts repair
stations, mechanics holding Inspection Authorization (IA), and
Principal Maintenance Inspectors (PMI) in the Flight Standard District
Offices (FSDO) of the potential of loose hex plugs in any Precision
Airmotive LLC RSA-5 series, RSA-10 series, or any Bendix RSA-5 series
or RSA-10 series fuel injection servo that meets the following criteria:
The servo was shipped on an engine, or installed as a spare, or repaired/overhauled before August 22, 2006; and
The brass hex plug, P/N 383493, does not have a letter “G” scribed or stamped on it.
These servos are installed on fuel injected Lycoming Engines IO, (L)IO,
TIO, (L)TIO, AEIO, AIO, IGO, IVO, and HIO series reciprocating engines,
regardless of displacement, Teledyne Continental Motors LTSIO-360-RB
and TSIO-360-RB reciprocating engines, and Superior Air Parts, Inc.
IO-360 series reciprocating engines.
At this time, there is no evidence to indicate that this airworthiness
concern is an unsafe condition that would warrant airworthiness
directive action under Title 14 of the Code of Federal Regulations (14
CFR) part 39.
Background
There have been two incidents pertaining to fuel injection servos
installed on Lycoming engines in which the brass hex plug, P/N 383493,
was found hanging by the safety wire, out of the hole, with damaged
threads. A disengaged hex plug will cause improper scheduling of fuel
flow and associated engine power loss. Emergency airworthiness
directive (AD) 2008-06-51 was issued mandating inspection of all
engines that had their servo replaced or worked on since August 22,
2006 and in which defective gaskets were installed under the hex plugs.
To adopt the emergency AD as an amendment to 14 CFR part 39, we
superseded it with AD 2008-08-14. An AD supersedure to incorporate a
terminating action to the repetitive inspections of that AD will be
forthcoming. While investigating the cause of the disengaged hex plugs,
we were made aware of several instances of loose plugs on servos that
did not have gaskets manufactured during the suspect time period. We
determined that the gaskets addressed in this SAIB may allow the hex
plugs to loosen, but we have no reports of these plugs coming out.
Recommendations
We recommend, as part of each normal annual inspection performed on all
airplanes powered by the engines listed previously in this SAIB, you
use Precision Airmotive Service Information Letter SIL RS-88, dated
June 16, 2008 (attached) for the following:
We recommend that you inspect hex plugs in Precision Airmotive LLC
RSA-5 and RSA-10 series, and Bendix, RSA-5 and RSA-10 series, fuel
injection servos that meet the previously described criteria in this
SAIB, for looseness, and if the plug is found to be secure, no further
action would be required.
If the plug is found to be loose, we recommend you replace the hex plug
gasket with gasket, P/N 2577258, and apply the increased installation
torque using steps 1 through 10 of Precision Airmotive Service
Information Letter SIL RS-88. We also recommend that you report plugs
found loose, to Richard Simonson at the contact information below,
unless otherwise reported.