Suspected Unapproved Parts Details
There have been failures of the flight deck and cargo compartment windows organic glass panes on the An-26 aeroplanes.
One of the main causes of these failures was attributed to the use of panes made of a glass material not conforming to approved design data (use of SO-120 not-oriented glass instead of AO-120 oriented glass) that causes decreasing of window physical and mechanical properties.
The suspected unapproved parts of organic glass (SO-120) should not be accepted for installation on the aeroplanes.
Recommendation: Maintenance organisations, aircraft owners, operators, independent certifying staff, manufacturers, and parts suppliers should determine if the parts are approved parts prior accepting them to their organisations or before fitting them to an aircraft.
If unapproved parts are found in stock, it is recommended that these parts are quarantined to prevent installation until a determination can be made regarding their eligibility for installation.
It is also recommended for maintenance organisations, aircraft owners, and operators to check if unapproved parts are not already installed on in-service aircraft. If so, these parts should be replaced with approved parts. The unapproved parts should be quarantined.