PILOT SPIN
Pilot Zone => Pilot Zone => Topic started by: acrogimp on October 03, 2016, 08:28:21 AM
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So, the Yak is down for its' conditional and as pat of the inspection we pulled an inspection cover to evaluate some play that Gennady Elfimov noticed in the left aileron when we did the pre-clinic inspection for the advanced spins and acro clinic I took in August. We went on to fly 12 very hard hours of spins and acro, then the plane flew a further 10-12 very hard hours during a twice-annual basic fighter maneuvers training clinic.
Fast forward to yesterday and we find the 'play' that was suspected to be some bearing wear was instead a failing repair from before the plane came to the US.
At some point, the outer aileron bracket was replaced, and the repair using pulled rivets was failing. 4 of about 14 rivets had failed completely, with half the rest 'working' as in already loose.
The Yak ailerons are extremely powerful and as a result can generate very powerful forces and loads, this was, no bullshit, an accident waiting to happen.
Since we were in that area last year for the Conditional and the installation of the LED lights and none of this was evident at the time, this repair was basically unzipping at a fairly rapid pace most likely accelerated by the last 20-30 hrs of flying which are the hardest the plane has seen since I bought it a year and a half ago.
Result will be cutting out part of the aileron cove for access, shooting proper rivets, and then installing a new, removable, cove closeout with thankfully minimal paint work. This was already an expensive conditional with some planned prop and other maintenance, but given my intention to fly more acro this year and next in prep for joining the airshow circuit eventually, this was a good if not unexpected catch.
Pay attention during those preflights and annual inspections.
'Gimp
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Pay attention during those preflights and annual inspections.
'Gimp
Absolutely!
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Nice catch.
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Glad you caught that before it created a real issue.