Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
NE-05-84 R1
September 10, 2009
This is information only. Recommendations
aren’t mandatory.
Introduction
This Revised Special Airworthiness Information Bulletin (SAIB) alerts
you, owners and operators of Bombardier-Rotax (Rotax) 912 A, 912 F, 912
S, and 914 F series reciprocating engines and facilities that maintain
and repair these engines, to revised information related to monitoring
of cooling system temperatures and the type of liquid coolant to use in
these engines. All other information remains the same. These engines
are installed on, but not limited to, 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, and
HK36 TTS; Iniziative Industriali Italiane 650 TC, 650 TCN, 650 TCS, and
650 TCNS; and Stemme GmbH S10-VT aircraft. These engines may also be
installed on amateur-built and light-sport aircraft. At this time, this
airworthiness concern is not an unsafe condition that would warrant
airworthiness directive (AD) 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
loss of coolant and engine overheating on Rotax 912 and 914 series
engines. Based on these findings, EASA published AD 2007-0155, dated
May 29, 2007, that requires use of a waterless type coolant if the
engine coolant exit temperature will exceed 120° centigrade (C).
Use of waterless coolant may not apply to all Rotax 912 and 914 series
engines because coolant exit temperatures are affected by the aircraft
installation and operating conditions. The maximum cylinder head
temperature limits approved for these engines remain the same.
If you use a conventional ethylene-glycol/water coolant, and engine
coolant exit temperatures exceed 120° C, loss of coolant, engine
overheating, knocking, and engine damage can occur, which could result
in an in-flight shutdown. You should monitor the coolant exit
temperature to prevent engine overheating when using conventional
coolant. You can also prevent engine overheating by monitoring cylinder
head temperature if an appropriate correlation is established between
coolant exit temperature and cylinder head temperature.
Rotax service bulletins SB-912-043 Revision 2, dated November 10, 2006,
and SB-914-029 Revision 2, dated November 10, 2006, provide additional
information about coolant usage. The applicable Rotax 912 and 914
installation manuals and operator’s manuals also provide related
information.
Recommendations
We recommend that you comply with the coolant usage information
provided in Rotax service bulletins SB-912-043 Revision 2, dated
November 10, 2006, and in SB-914-029 Revision 2, dated November 10,
2006, and the applicable Rotax 912 and 914 installation manuals and
operator’s manuals.
We also recommend that you comply with the coolant usage information
and cooling system temperature limits defined by the manufacturer of
your aircraft because of installation effects on engine cylinder head
and coolant exit temperatures.
For Further Information Contact
Richard Woldan, Aerospace Engineer, FAA, Engine Certification Office,
12 New England Executive Park, Burlington, MA 01803; telephone:
781-238-7136; fax: 781-238-7199; e-mail: richard.woldan@faa.gov.