Diamond DA 20 CI - Service Difficulty Alert

AL 2004-02
15 March 2004

Engine Mount Bolt Washer

Upon investigation of the nose area of DA20-C1, it was discovered that the L/H lower engine mount to the firewall attach bolt was under torque at 5 ft/lbs. The manufacturer specified torque is 25 ft/lbs. The R/H mount bolt was also discovered to be under torque at approximately 5 ft/lbs.


The operator carried out a fleet-wide inspection and additional upper and lower engine mount attach bolts were discovered with 5 to 8 ft/lbs torque values. The engine mount washer, P/N MS21306-1C, under the head of bolt, PN AN 6-23A, was also discovered damaged. (Photo 1). The MS21306-1C washer has an inside diameter equivalent to an AN-7 washer. The bolts installed on the engine mount are AN 6-23A. (Photo 2). The washers progressively failed, causing loss of torque. Upon disassembly, the engine mount washer was discovered "cupped". (Photo 3).


Diamond Aircraft has issued a Service Bulletin to address this concern. Transport Canada strongly recommends owners and operators of this aircraft, at their earliest opportunity, confirm the torque of the engine mount bolts as described in Diamond Service Bulletin DAC1-71-02.

Any further defects or occurrences should be reported to Transport Canada, Continuing Airworthiness, Ottawa via the Service Difficulty Reporting program.


For further information, contact a Transport Canada Centre, or Mr. Jean Grenier, Continuing Airworthiness, Ottawa, telephone (613) 952-4343, facsimile (613) 996-9178 or e-mail grenije@tc.gc.ca

For Director, Aircraft Certification

Ray Raoux
for Bohdan Goyaniuk
Chief, Continuing Airworthiness