Dual mag future

[OR75]

49 minutes ago, 201Steve said:

There wasn’t much of the stud protruding past the nut, not a sure fire way, but I was suspicious from other finds. I threw a torque wrench on it to confirm. Wasn’t even close. 

The top bolt is easy to torque 

the bottom torque is a pain to get to and you need the right length extension to put the wrench at the right location between  the firewall and the bolt 

Removing the top cowl is not an every flight occurrence ´. However , it is possible to reach via the oil cap door and check the mag is not loose 

[carusoam]

Summary of why MSers OH their mags on separate time cycles...

1) mags and vac pumps wear pretty heavily with time...

2) 500hrs of use can be acceptably counted on...

3) OH after 500hrs makes sense...

4) both mags and vac pumps suffer from infant mortality... for various reasons...  So having them on different time schedules makes a lot of sense...

5) The oddity of human failure... it happens...  enough that somebody said two heads are better than one...   and it is the reason why a PPI is done independently of the existing maintenance team...

6) PPIs are financially important...   star washers are engine life important... both have been messed up easily in the past...

PP summary of stuff I have read around here...

Best regards,

-a-

[EricJ]

2 hours ago, PT20J said:

Torque seal is a great thing. Sometimes we get interrupted. It's easy sometimes to lose track of which bolts got torqued and which didn't. Having a rule that torque seal is immediately applied after proper torqueing is a great way to be sure.

A  friend that worked at United's maintenance depot at SFO told me years ago that they had found so may tools inside airframes that they made a rule that you could not set a tool down on an airframe. It sounds great. Try it -- it's really hard. But if you do it you won't wonder where that missing wrench got to.

Skip

Some applications/outfits require tool inventories after each job, to make certain nothing got left behind.    Sometimes to facilitate this tool cutouts or placements are used to make it easier to tell something is missing.   Some applications even put bar codes on each tool and they have to be checked out and checked in for each job, and there are fancy tool boxes now that do this automatically with some tools.

I don't know whether this level of tool security has reached aviation yet, or at least commercial aviation.

 

[Bartman]

13 hours ago, PT20J said:

Torque seal is a great thing. Sometimes we get interrupted. It's easy sometimes to lose track of which bolts got torqued and which didn't. Having a rule that torque seal is immediately applied after proper torqueing is a great way to be sure.

A  friend that worked at United's maintenance depot at SFO told me years ago that they had found so may tools inside airframes that they made a rule that you could not set a tool down on an airframe. It sounds great. Try it -- it's really hard. But if you do it you won't wonder where that missing wrench got to.

Skip

During engine installation I personally applied torque seal to every bolt, nut, clamp, and hose connection, basically everything that did not have safety wire. It has the added benefit of being fluorescent under UV light and makes it easy for me and my maintainer to see that nothing has changed.
 

Although not foolproof, I do stick my hand in thru the oil filler door and try to shake the magneto before engine start. I have done this since about 2008 when I asked my local mechanic at the time to investigate an oil leak after maintenance done at a different but well known shop a few hours hours prior. First thing he did was stick his hand thru the oil fill door, smiled, and asked me to shake the dual mag. Interestingly not long after that and despite having less than 500 hrs that magneto died in flight on one side which I realized by all EGTs about 100 degrees higher than normal.  It would not restart even for taxi to the shop, only “backfire”.  So I could get back in the air quicker we got an exchange, and were told the old one had teeth missing on a gear.  Sounds familiar and I am convinced the loose magneto contributed to subsequent failure.

Now we all have new style clamps, but I also specifically insist and ask questions about the torque and use of new star washers every time the magneto is serviced.