Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
NE-08-36
July 16, 2008
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin alerts you, registered
owners and operators of BRPRotax (Rotax) 912 A, 912 F, 912 S, and 914 F
series reciprocating engines, of possible abnormal camshaft and
hydraulic valve tappet wear. These engines are installed on, but not
limited to the following aircraft: Aeromot-Industria Mecanicao
Metalurgica AMT-200, AMT-200S, and AMT-300, Aquila Technische
Entwicklungen GmbH AT01, Diamond Aircraft Industries (Austria and
Canada) DA20-A1, HK36 R, HK36 TC, HK36 TS, HK36 TTC, HK36 TTC-ECO, HK36
TTS, Iniziative Industriali Italiane 650 TC, 650 TCN, 650 TCS, 650
TCNS, and Stemme GmbH S10-VT. These engines might also be installed on
amateur built and light sport aircraft. At this time, this
airworthiness concern isn’t an unsafe condition that would warrant
airworthiness directive action under Title 14 of the Code of Federal
Regulations (14 CFR) part 39.
Background
The European Aviation Safety Agency (EASA) has advised us of possible
abnormal camshaft and hydraulic valve tappet wear on certain Rotax 912
and 914 series engines. Service experience indicates that this
condition might affect one or two valves on each engine and result in a
rough running engine and reduced engine power. This condition could
result in an in-flight engine failure if allowed to progress. Based on
these findings, the European Aviation Safety Agency (EASA) published
airworthiness directive (AD) 2006-0316R1, dated March 13, 2008, that
requires initial and repetitive inspections of a magnetic plug to
identify abnormal camshaft or valve tappet wear.
The related Rotax service bulletins define the population of engines that may be susceptible to this condition as follows:
912 A series engines from serial number 4,410.681 to serial number
4,410.712, 912 F series engines from serial number 4,412.912 to serial
number 4,412.921, 912 S series engines from serial number 4,923.263 to
serial number 4,923.380, 914 F series engines from serial number
4,420.595 to serial number 4,420.637, as well as any 912 or 914 series
engines that have had the camshaft or the hydraulic valve tappets or
both replaced after January 1, 2006 through and including December 1,
2007.
The inspections are not needed on engines that have hydraulic valve
tappets, part number (P/N) 854.095, installed during production and
engines that have spare part kit, P/N 881.831, (which includes
hydraulic valve tappets, P/N 854.095) installed during engine repair or
general overhaul. Engines with hydraulic valve tappets P/N 854.095
installed prior to delivery by BRP-Rotax can be identified by (minor)
modification number references for each specific engine design as
follows: 85-05 for 912 A; F50-05 for 912 F; S34-04 for 912 S; and
F45-04 for 914 F engines. These reference numbers are documented in
each individual engine Release Certificate.
BRP-Rotax service bulletins SB-912-051 and SB-914-034 (each dated
January 30, 2008) provide additional information related to inspecting
the magnetic plug.
Recommendation
We strongly recommend that you inspect the magnetic plug of the
affected engines using the schedule and procedures defined in
Bombardier-Rotax alert service bulletins SB-912-051, dated January 30,
2008, or SB-914-034, dated January 30, 2008, as applicable.
For Further Information Contact
Richard Woldan, Aerospace Engineer, FAA Engine Certification Office,
ANE-142, 12 New England Executive Park, Burlington, MA; phone:
781-238-7136; fax: 781-238-7199; e-mail: richard.woldan@faa.gov.