You shouldn't get many problems on linkages or indeed cables, fatigued metal will tend to go greyer slightly lighter and have a granular surface appearance in some cases if that makes sense, but you should never get that type of forces on it.
I myself change any cables that show signs of polishing at all on the Annual Inspection, this is for 2 reasons, one and the primary one is safety and the other is downtime, if it needs replacing later on in the year........ there are acceptable limits but i just replace them.
There is a manual issued by Cessna that covers higher houred 100 series aircraft and what addition things to look at based on their experiances and feedback........ Nothing really in it I do not do already and nothing your Engineers would not normally be looking at...
To be honest one of our worst enemies to fatigue is the pilot, In this I mean when one has a hard landing etc, they would rather keep it quiet and to themselves, this can have a detrimantal effect as checks we would normally carry out in these instances do not get done...
I had a person who came to me sheepishly of late and told me when moving the aircraft on the steering arm he had clipped the tip light....... He expected me to be upset and was suprised that I thanked him for his honesty, but his honesty allowed me to check not just the light but the wing structure itself... people do not realise the forces that can be exerted further down the wing from a slight impact on the wing tip.
I remember the report on a Robin pilot in the UK that clipped a haybale taxying, no visual damage to the wing or very little, so he moved the bale and continued on his flight, I believe the wing separated and he was killed. That is why honesty is important..
As for the larger light stuff, Well, Cessna concerned about the amount of large twins still flying Cessna 421's etc, something not envisaged when built. So they bought a couple of high houred examples, stripped them down to the component parts, inspected them and issued some service bulletins (SID's) on what it found required to be carried out to maintain the aircraft in flyable conditions... this involved pulling the wings and inspecting the mountings, inspecting the windscreens( Pressurised) and also the fuselage etc...
Last edited by NutLoose; 30th July 2007 at 02:49.