ASN Wikibase Occurrence # 1066
Last updated: 22 May 2013
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Narrative:During a normal 3-point landing on grass Runway 27 at Whiterashes Airfield, the tailwheel leaf spring failed allowing the tailwheel to separate. However, the fractured spring acted as an effective tailskid, keeping the rear fuselage clear of the ground, and control of the aircraft was not materially affected. As the outer section of spring and tailwheel had separated from the aircraft, it had moved upward into the bottom edge of the rudder and caused local deformation.
|Operator:||Aberdeen Auster Flying Group|
|C/n / msn:|| 2075|
|Fatalities:||Fatalities: 0 / Occupants: 1|
|Airplane damage:|| Minor|
|Location:||Whiterashes Airfield, Aberdeen -
|Departure airport:||Insch, Aberdeenshire|
|Destination airport:||Whiterashes Airfield, Aberdeen|
The pilot reported that the leaf spring had fractured near its lower end, close to the point of attachment of the castering tailwheel unit. Inspection of the fracture revealed two lobes of clean metal on the fracture surface, whilst the rest of the surface was slightly discoloured with oxidation. Photographs provided by the pilot identified the region of failure as being through the third and final section of the three-leaf spring, coincident with the point where the second leaf terminated and the third leaf extended downward to the point where the tailwheel attached.
Both the character of the fracture described by the pilot and its location adjacent to, or just beneath, the end of the adjoining leaf were considered features typical of a leaf spring which had suffered fatigue cracking in service. Such cracks in leaf springs are difficult to detect when carrying out a general visual inspection, not only because they are usually very 'tight' cracks but also because of their close proximity to the end of the adjoining spring leaf; often the crack is just out of sight beneath the end of the adjoining leaf. The inherently dirty environment in which the spring operates is an additional factor which makes crack detection difficult. In addition, because of the relatively brittle and notch-sensitive nature of spring steel, final overload fracture of the remaining spring section often occurs before such a fatigue crack has extended to any significant depth.
AAIB Bulletin No: 8/2000 Ref: EW/G99/10/17 Category: 1.3 http://www.caa.co.uk/application.aspx?catid=60&pagetype=65&appid=1&mode=reg&fullregmark=AIJT
||Dr. John Smith
||Updated [Operator, Departure airport, Source, Embed code, Narrative]|
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