Originally published at: NTSB: It Just Takes One Loose Nut
Improperly secured B-nut went undetected during recent annual inspection. It led to a fatal accident.
My beef is with the Annual inspections which I think cause more problems than they find. I’ve owned a 210 for 39 years and I can say that the majority of the times Post annual from dozens of different shops the aircraft is returned with some maintenance induced squawk. Taking the airplane apart after 60-70 hrs is overkill by a lot. It should be increased to every 2 years especially if it is hangared and flown under 150 hrs during that period.
Less maintenance is better. The annual inspection is too invasive and should be reduced to a much more limited scope that can be performed visually, without taking things apart. I wish AOPA would take this up with the FAA and work through policy making and legislation to simplify annual inspection requirements.
" The do not trust their God to rouse them a little before the nuts work loose"
Rudyard Kipling The Sons of Martha. Should be over the entrance to every maintenance shop.
I agree, light aircraft tend to be over maintained. I remember over 50 years ago talking with some Royal Australian Air Force Huey pilots about their helos. They reckoned when they went on exercise with the grunts and got them out of the clutches of the maintainers they were much more reliable.
Personally I’ve seen more problems in sailplane world from maintenance than lack of.
The folks that are addressing the Annual inspection issue are missing a point. The fitting was loose because a JPI was installed. Was that before, during, or after the Annual?
The use of torque seal would make inspecting the work done a lot easier. A&P mechanics should use it a lot more. Owners should insist that it is used to make it possible to better inspect the work.
Unfortunately, most pilots don’t take much interest in maintaining or learning about such things. If I just had a 100 hour done I would be down there before it was buttoned up and look and put my hands on everything that was done. You never know what you might find. The life you save might be your wife, son, or daughter.
My brother’s partner in their Cherokee was hopping to Orcas Island from Bellingham - you cut the power from takeoff to land. It’s a good thing. The updraft carburetor dropped off the engine on power reduction as there was not oven one bolt installed to hold it there. Immediately after an annual, of course. Amazing it didn’t fall during the run up. He simply declared and dropped it onto the runway. The good news is their repair shop took incredibly good care of them after that! (Besides the fact no one was so much as injured or even inconvenienced much.)
It’s not the annual. It’s ground running and performing a proper leak check. And never tighten a b nut finger tight and walk away. Have the proper wrench in hand to tighten it before walking away.
That’s not where the failure occurred. It happened at the flow divider which is downstream from the fuel flow meter.
Torque seal was used in my boss’s accident. The same B nut was 1/2 turn loose. My boss wound up with a broken back and confined to a wheelchair. He got a lot of money from the engine overhauler though. He was pretty messed up from a previous accident.
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