SB912064Today, Rotax released four service bulletins for the 912 and 914 series engines.  These bulletins are serial range specific.

Engine type Serial number
912 UL from S/N 6,770.159 up to S/N 6,770.596 inclusive
912 ULS S/N 6,777.436/
from S/N 6,777.492 up to S/N 6,777.508 inclusive/
S/N 6,777.514/
from S/N 6,777.526 up to S/N 6,777.873 inclusive/
from S/N 6,777.875 up to S/N 6,779.168 inclusive/
from S/N 6,779.170 up to S/N 6,779.581 inclusive/
from S/N 6,779.616 up to S/N 6,779.623 inclusive/
S/N 6,779.679/ S/N 6,779.705/ S/N 6,779.738
914 UL from S/N 6,774.138 up to S/N 6,774.160 inclusive/
from S/N 6,774.165 up to S/N 6,774.172 inclusive/
from S/N 6,774.176 up to S/N 6,774.268 inclusive/
from S/N 6,774.270 up to S/N 6,774.915 inclusive/
S/N 6,774.924/ S/N 6,774.959
912 A from S/N 4,410.884 up to S/N 4,410.940 inclusive
912 F from S/N 4,412.984 up to S/N 4,413.005 inclusive
912 S from S/N 4,924.042 up to S/N 4,924.358 inclusive
914 F from S/N 4,420.965 up to S/N 4,421.088 inclusive
NOTE: Crankshafts with the following serial number (S/N) that were installed or
delivered as spare parts in the above-mentioned engines and short blocks
(from S/N 9999627 up to S/N 9999678 inclusive) are also affected, if removed:
S/N 40232 up to S/N 44338 inclusive

Why:
Due to a deviation in the manufacturing process some crankshafts may develop a crack on the power take off side. These cracks can cause breakage of the crankshaft in the support bearing during operation. In this case the function of the support bearings (consisting of 3 main bearings and 2 support bearings) is compromised. The operating reliability, however, is given until the next maintenance.

When:
– During the next mandatory maintenance event, prescribed by BRP, or at the next 100 hours of operation, the checking of the crankshaft journal (power take off side) must be performed on the engines listed in section 1.1) according to the following instructions in section 3. If the engine was operated less than 100 hours of operation during one year, an inspection should also be performed every 12 months.
See also chapter 05-20-00 “Scheduled maintenance checks“ of the current Maintenance Manual (Line) of the respective engine type.
– Periodically at every additional 100 hours of operation, this check of the crankshaft journal (power take off side) has to be performed on the engines listed in section 1.1) according to the following instructions in section 3.
– Up to a TSN of 1000 h this periodic checking of the crankshaft journal (power take off side) must be performed on the engines listed in section 1.1) according to the following instructions in section 3.

NOTE:  In the event of a sudden drop in oil pressure of at least 0.5 bar (7.3 psi) in the same operating point (also within operating limits) the checking of the crankshaft journal (power take off side) must be conducted as soon as possible on the engines listed in section 1.1) according to the following instructions in section 3. This sudden drop in oil pressure can be a symptom of a broken crankshaft journal.

How:
Be sure to download SB-912-064 – this will give technicians detailed directions on how to perform the inspection.

Who:
This depends on how the aircraft is registered.

For the checking procedure in:

SLSA (USA) A technician with a current iRMT rating of Service or Higher and either a LSRM or A&P
CERTIFIED A technician with an A&P rating with type specific training (current iRMT Service Level or higher)
EXPERIMENTAL The owner of the aircraft.

Some common sense applies here.  You may be allowed to do the inspection, however if you do not feel comfortable with completing a task, seek professional assistance.  It must be remembered that for maintenance Rotax states ” It is a requirement that all organizations or individuals possess the required special tooling. Technicians must have type-specific training and keep a recurrent knowledge status for the level of work they intend to perform. Technicians may require accreditation from their local aviation authority in addition to any BRP-Powertrain requirements.”

Downloads:
SB-912-064-UL, SB-912-064, SB-914-045, SB-914-045-UL