Summary
We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:
Since 2004, more than 30 reports have been received of in-flight loss of a rear passenger door on Diamond aeroplanes, the majority of which were DA 40. In additional, at least 18 doors have been replaced because of damage found on the hinge.
Diamond Aircraft Industries conducted analyses and structural tests to determine the root cause of the door opening in flight. The conclusions were that the primary locking mechanism provided adequate strength to react to the loads in flight. It was also determined that the root cause was the crew not properly securing the rear passenger door by the main locking mechanism, prior to flight. Damage tothe hinges has been caused primarily by external loads (wind gust conditions) while the aeroplane was parked.
All DA 40 and DA 42 aeroplanes have a system installed that provides a warning if the main door latch is not fully closed and a secondary safety latch (with retaining bracket) design feature. The initial intended design function of the latch was to hold the rear passenger door in the "near closed'' position while on the ground, protecting the door from wind gusts. However, the original retaining bracket Part Number (P/N) DA4-5200-00-69 might not hold the door in this "near closed'' position while in flight * * *.
This condition, if not corrected, could result in the rear passenger door opening and departing the aeroplane in flight.
The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.