EASA SIB 2009-25
EMBRAER EMB-135 and EMB-145 Series Aeroplanes — WindowsTM version of Personal Computer Memory Access (PCMA) Software on the AH-800 Attitude & Heading Reference System (AHRS)
Summary
EASA Safety Information Bulletin SIB No. 2009-25 is an informational bulletin concerning EMBRAER EMB-135 and EMB-145 series aeroplanes equipped with the AH-800 Attitude & Heading Reference System (AHRS). It announces the availability of a new WindowsTM version of the Personal Computer Memory Access (PCMA) software used for ground support and configuration of the AH-800 AHRS. The bulletin highlights the risk of incorrect AHRS configuration potentially causing an inverted attitude display, which could lead to loss of control.
What Changed
The bulletin introduces a new WindowsTM-based PCMA software version for the AH-800 AHRS, replacing the older DOS-based version. This new software is split into two packages for flux valve calibration and configuration programming, designed to eliminate the root cause of potential attitude display inversion. EMBRAER has also published a special maintenance task in the Aircraft Maintenance Manual to address this issue.
Why It Matters
This information is critical for operators and maintenance organizations of EMBRAER EMB-135 and EMB-145 aircraft fitted with the AH-800 AHRS, as incorrect configuration of the AHRS can result in an inverted attitude display and possible loss of control. Using the updated software reduces the risk of such configuration errors, thereby enhancing flight safety and operational reliability. Compliance teams should be aware that this bulletin does not mandate an airworthiness directive but strongly recommends adopting the new software.
What To Do
Operators and maintenance personnel should obtain and use the new WindowsTM PCMA software packages from Honeywell for configuring the AH-800 AHRS as described in EMBRAER Service News Letter 145-34-0054 Change No. 01. They should also follow the special maintenance task published in the Aircraft Maintenance Manual to ensure correct AHRS configuration. There is no mandatory compliance deadline, but prompt adoption is recommended to mitigate the risk of attitude display inversion.
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