Nose landing gear fork assembly - Inspection / replacement - Civil Aviation Safety Alerts (CASA) No. 2011-07


Owners and maintainers of Diamond Aircraft Industries INC., aeroplane models DA20-A1 and DA20-C1

Issuing Office: National Aircraft Certification Branch
Document No.: CASA-2011-07
File Classification No.: Z 5000-35
Issue No.: 01
RDIMS No.: 6572085
Effective Date: 2011-10-21


This Civil Aviation Safety Alert (CASA) is issued to inform owners and maintainers of a potential unsafe condition regarding cracking of the nose landing gear fork (NLG) assembly.


Cracks have been discovered on the NLG fork assembly, part number (P/N20-3220-08-00, during routine NLG inspections. The cracks appear just above the axle hole on the cut out flange.  A review of the Service Difficulty Report Database from 2005 to 2010 has revealed 10 reports concerning this issue.

In order to better detect cracking of the NLG fork assembly, Diamond Aircraft Industries has revised their DA20-A1 and DA20-C1 Aircraft Maintenance Manual Chapter 05-20-00, Scheduled Maintenance Checks. These changes require more frequent and more detailed inspections. Furthermore, Diamond offers a more robust fork assembly, P/N 20-3220-08-00_1, as a replacement for the original P/N 20-3220-08-00. The new part will be installed on new production models and supplied for future procurement orders.

Further detail on this product improvement is available from Diamond Service Information Letters SIL20A1-008 and SIL20C1-005 or by contacting Diamond Aircraft Industries Inc. at

Recommended action:

Transport Canada Civil Aviation (TCCA) recommends aeroplane owners and maintainers acquaint themselves with and adhere to the changes in Diamond’s revised inspection schedule. TCCA also recommends aeroplane owners replace their original NLG fork assembly with the improved part.

Contact office:

For more information concerning this issue, contact Robert Dixon, Accident/Incident Investigation, Continuing Airworthiness, National Aircraft Certification in Ottawa, by telephone at 613-952-4308, by fax at 613-996-9178 or by e-mail at

For the electronic version of this document, please consult the Quick Links section of the following Web address:

For the Director, National Aircraft Certification


Derek Ferguson
Chief, Continuing Airworthiness

The Transport Canada Civil Aviation Safety Alert (CASA) is used to convey important safety information and contains recommended action items. The CASA strives to assist the aviation industry's efforts to provide a service with the highest possible degree of safety. The information contained herein is often critical and must be conveyed to the appropriate office in a timely manner. The CASA may be changed or amended should new information become available.