2014-34 912 A/F

Suspected Unapproved Parts Details

Product
Multiple
Part Number
912 A/F
Serial Number
413235 or 413236

This SIB is issued to alert aircraft Type Certificate (TC) and Supplemental Type Certificate (STC) holders, owners, operators, repair facilities and engineers of possible service difficulties, including engine failures during flight, arising from unnoticed exceedances of approved engine coolant temperature limits due to installation of an unapproved design.
The reported conditions are the result of an insufficiently communicated engine design change which altered the engine/aircraft interfaces by substituting the previous cylinder head temperature (CHT) measurement (limit temperature 135°C/150°C) with a coolant temperature (CT) measurement (limit temperature 120°C).
This design change is currently not identified by the engine model designation or the engine P/N but only through the cylinder head P/N and the position of the temperature sensor:
CHT measurement  temperature sensor points downward CT measurement  temperature sensor points upward. If affected engines or cylinder heads have been or are installed during production or maintenance without concurrent installation of an adequate aircraft TC/STC holder approved modification, thus altering the previous aircraft CHT indicator/indicator markings/aircraft flight manual limitations, then coolant temperature with a maximum engine operating limit of 120°C (valid for engines operated with water diluted glycol coolant) is displayed on a CHT indicator with a typical limit marking (red radial/range) of more than 120°C. The pilot is therefore not able to identify coolant limit exceedances, subsequent loss of coolant and impending engine failure during flight. Also, for engines operated with approved waterless coolant, installation of the affected engines needs to be accompanied by adequate aircraft TC/STC holder approved modifications to assure safe aircraft operation.
Installation of affected engines and spare parts without concurrent incorporation of aircraft TC/STC holder approved modifications, even if unintended and unnoticed by production or maintenance, constitutes an unapproved aircraft modification.
Investigations are ongoing at BRP-Powertrain and with aircraft TC/STC holders to identify the extent of unapproved installations and to evaluate potential mandatory airworthiness actions. At this time, the safety concern described in this SIB is not considered to be an unsafe condition that would warrant Airworthiness Directive (AD) action under EU 748/2012, Part 21.A.3B.

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