Words of Advice:

"If Something Seems To Be Too Good To Be True, It's Best To Shoot It, Just In Case." -- Fiona Glenanne

"Flying the Airplane is More Important than Radioing Your Plight to a Person on the Ground
Who is Incapable of Understanding or Doing Anything About It." -- Unknown

“Never argue with stupid people, they will drag you down to their level
and then beat you with experience.” -- Mark Twain

"Stay Strapped or Get Clapped." -- probably not Mr. Rogers

"Eck!" -- George the Cat

Monday, August 27, 2012

For the Reuse of Lock Nuts, an Airplane Was Lost

That is pretty much one of the findings of the NTSB following the 2011 crash at the Reno Air Races.

I thought that reusing those locknuts with the plastic/fiber inserts was long-ago considered to be a serious Bozo No-No. Maybe Busted Knuckles, Eck! or Fixer will chime in on this.


Eck! said...

I use those only for noncritical places where safety wire IS NOT possible. Also reusing them
is also a bad idea as the plastic/fiber used
takes a set over time. When used they could be checked for correct torque.

With that planes do use them but observe where they are common, most of the places are not critical or fall into those blind spots where
nothing else can serve.


Phil said...

Nylocks, as they are known, are the "modern" replacement for the good old fashioned castellated nuts used for ages that you put a cotter pin through to make damn sure they didn't back out. Outer wheel bearing nuts and tie rod ends on automobiles were a very common place to find them.

Those nylon insert nuts are a pain in the ass going on and coming off and they will, as ECK! pointed out, also "take a set" meaning that the nylon will actually have threads formed in it.

They are indeed supposed to be a one time use, especially for critical parts fastening for just that reason.
I have seen some rather large ones too, over two inches across, used to hold the u joint yoke on the splined shafts for both the transmission and differentials on heavy duty trucks for example.

BTW, thanks for thinking of me and for stopping by my place.


BadTux said...

Yeppers, like 'Nucks sez, single-use-only. And if used in someplace where backing out would bring the possibility of death, safety wire or one of those castellated nuts. My old KLR650 motorbike had the castellated nuts on its axles and I was quite happy about that.

If you have a plane that you've probably put hundreds of thousands of dollars into, re-using nylocks is just plain insanity. Just sayin'.

Comrade Misfit said...

Indeed, it was insanity.

Flyable P-51s are worth over a million, some, over two million. Making one race-ready costs hundreds of thousands of dollars.

And they were too cheap to buy new locknuts?

Dr. Bubbles said...

"collided with the airport ramp"

As an editor I loathe the overuse of "impact" to mean "affect". But there are times when "impact" is the appropriate verb, and this was one of them.