Light Aircraft Association Publishes New Mandatory Technical Directive

The LAA has released MTD-01-2025 -- for the 'Inspection of horizontal stabilizer (tailplane) attachment brackets and associated hardware for cracks, looseness and other forms of distress' is issued for Zenair CH601, CH650, CH701, CH750 and variants of these four models. 

LAA states that a number of cases have been found whereby the structural integrity of the horizontal stabilizer mountings on the Zenair types identified above have been compromised by one or more of the following: 

• Cracking Of The Attachment Brackets 
• Oversize Holes 
• Loose Rivets 
• Distorted And Chafed Brackets

They note that these problems could occur due to a number of factors including poor build quality, a build-up of tolerances in the positioning or dimensions of the brackets, improper assembly, rough treatment or in-flight vibration. Failure of a tailplane attachment could result in degraded controllability in flight or loss of control. 

Special inspections of this area have been recommended by Zenair since January 2017, in their document ‘Mandatory Action. Jan. 2017 – Inspection of Horizontal Stabilizer tail attachment brackets’. This Mandatory Technical Directive mandates this safety action for aircraft operating on LAA Permits to Fly.

Based in the UK, the LAA supports the amateur built aircraft movement and provides comprehensive engineering facilities that support their Permit to Fly airworthiness system. 

FMI: www.lightaircraftassociation.co.uk/news/mandatory-technical-directive-issued-for-many-zenair-types, www.lightaircraftassociation.co.uk/infolibrary/45713298-1aef-44f1-b405-10378d11e9fe