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Foreman handed me a torque spec sheet from 1974 and I finally get why the old guys laugh at us
I was doing a gearbox reseal on a King Air last Tuesday in Spokane and the foreman slid over a photocopied torque sheet from a 1974 manual, coffee stains and all. Turns out the old spec called for 90 inch pounds on those case bolts instead of the 110 we use now, because the newer gasket material compresses different. He said the updated number showed up sometime in the 80s and nobody ever explained it, we just memorized the new one. Now I keep a copy of the old sheet in my box and check it before assuming the current manual has the whole story. Anyone got other specs that quietly changed like that without a note in the log?
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umathompson10d ago
Old sheets are great for context but the current manual is what the plane gets signed off against, so mixing them is how you end up with a torque cal that nobody can defend in an audit. The fix is getting engineering to put a note in the maintenance log explaining why the number changed, not just keeping a personal copy of a 1974 page. Knowing the history is smart, but the approved data is still the approved data.
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