Maintenance Induced Failure

[Guest]

1 hour ago, steingar said:

OK, I'll be the dumb kid and ask how a loose magneto caused oil to go everywhere.  I thought magnetos were electrical thingamabobs from an age when cars had chokes and women wore slips.

If you look carefully at the picture with the yellow rag, you will see the upper right magneto mounting stud.  It has no nut, lock washer or mounting clamp, also visible is a large gap between the magneto flange and the engine case.  Oil will escape at a good rate when the magneto comes loose to the point of falling off.

Clarence

[carusoam]

Thanks to Clarence for pointing out the detail....

I put a circle and an arrow to what I think Clarence described...

Thanks again to Alex for letting us get as much Mooney knowledge spread from the one incident...

Best regards,

-a-

[Shadrach]

On 5/8/2019 at 11:01 PM, alextstone said:

First, I apologize in advance for the length of this post.  Here's a teaser image to entice you to read on:

 

There is just no brief way of telling this story and I think it is one worth sharing.  Like so many others on this forum, I gleefully took delivery on my new to me "forever ours" Mooney last fall, a '95 Bravo.  Since then, I have been diligent about learning all I can about proper maintenance and monitoring of the condition of the engine and other components.  Once all of the more urgent issues were addressed (overhaul of the exhaust system and turbo, new cylinder, TKS troubleshooting) the time finally came for installation of a JPI EDM 830 and a trip over water to the Bahamas.   The planning for both started months ago (selecting and ordering life vests, a PLB, stobes, planning our day trips, learning about eAPIS and customs documents, applying for a Customs sticker and FCC radio license, etc). 

About two weeks before my wife and I were planning to depart, I purchased the EDM 830 and dropped the plane off at my local IA / A&P's shop for installation and an oil change.  The day before we left, I picked up the plane, test flew it around the pattern, and I discovered that one of the CHT and EGT probes were swapped which was quickly remedied.  The mechanic also informed me at that time that the MP sensor was defective out of the box and JPI would send another one.  I would have to return for its installation later - no big deal.  I then flew the plane again back to my home base in the neighboring town without incident.  

Our plan was to leave the next morning and to fly from KHBG via HEVVN intersection to KFXE, a flight that we could easily make in about 3 hours 45 minutes.  That night, my wife commented that she had intended to ask her parents to bring our snorkel gear home from their condo in Gulf Shores Alabama but that she forgot.  She begged me to make a stop the next morning on the way down to FL to pick them up and I agreed.  Again, no big deal, Gulf Shores is on the way and we have a car stationed at the airport KJKA.  

The next morning, after a thorough pre-flight (oil level at 8 quarts), we took off for our 28 minute flight to KJKA.  Here is the flight log from Flight Aware:

 

The flight was smooth and uneventful until about the last 4 minutes, right about the time you see the turn due south to set up for landing.  During my descent, partly because my JPI 830 was brand new, I was somewhat fixated on it during this flight so I was literally looking at it when I noticed a jump in the TIT to about 1675 degrees.  Here is the graph from SavvyAnalysis from that timeframe (minus the MP because of the faulty sensor):

 

At the time, I advanced the mixture to bring the TIT down and refocused on setting up for a safe landing.  I kept an eye on the JPI and I did not see anything else of concern.  BTW, I had mine mounted right beside my Aspen 1000 pro at the sacrifice of the stock VSI:

 

We exited the airplane, and I was shocked to see oil all over the place!  No, there was absolutely none on the windshield, though.  

 

Needless to say, I called my AI.  To his credit, he immediately hopped into his own plane (a Mooney) and flew down with tools to investigate.  This is what we discovered:

The right magneto was loose...literally.  Again, to my AI's credit, he inspected everything very thoroughly, apologized profusely, and re-installed the mag while cleaning up copious amounts of oil.  It took 5 quarts to bring the level back to 8 quarts so I narrowly missed the teardown requirement!  We test flew the aircraft without incident.  After a long discussion with my wife, we agreed that we would continue on the next morning to Apalachacola then Ft. Lauderdale, monitoring closely along the way.  We did so without further incident.  We overnighted at Banyan and continued to Governors Harbor the next day:

 

 

 

It truly was a trip of a lifetime!  I have asked myself many times what I could have done differently and what lessons there are in this experience.  So far this is what I have arrived at:

 

1.  It is not prudent to take a trip away from home base right after maintenance.

2.  The more post-maintenance inspection the better.

3.  When the monitor shows an anomaly, take it very seriously.

4.  Give the person who made an error an opportunity to make it right.

5.  Distraction is a dangerous thing (I'll elaborate on this on in a subsequent post).

I hope that this PIREP elicits some good discussion around MIF (Maintenance Induced Failure) and that additional lessons will be brought forth.  I truly appreciate this forum and I hope to meet some of you at Oshkosh this year (my first year to participate in the caravan!).

Fly Safe,

Alex

So did he retime the mag in the field?

Edited May 10, 2019 by Shadrach

[David_H]

Thanks for sharing this. Maintenance induced failure is very real.

Could this have been caught during the post maintenance run-up by the shop? Did they do one?

[Yetti]

5 minutes ago, David_H said:

Thanks for sharing this. Maintenance induced failure is very real.

Could this have been caught during the post maintenance run-up by the shop? Did they do one?

Probably not.  vibration loosened the nuts. This is caught by good work practices like Mooney Doc described.   How I do it. is to let's say you have 4 bolts.   Hand start them.  Faster to spin them on by hand. Use criscross to snug up with wrench.  Bring to final torque values with criscross.   Then go back around not hitting the torque values just to be sure you did not miss one.    You don't torque things twice.  That is bad form.    Then might put a hand on things to make sure things are not loose.  Then visual inspection to make sure things look right.    Just like a pilot that thinks the gear is down or that the frequency is correct.  People make mistakes because they thought they did something.   Not an AP or IA.

[Yetti]

contributing factors on the RCA would be "need to install an engine monitor before a big trip"   Work practices by the shop/mechanic.   I don't trust the mechanical condition of the plane after big things till after a RTS flight and 5-10 hours of flight time.

[alextstone]

17 hours ago, Shadrach said:

So did he read time the mag in the field?

Yes.  I watched him do it.

[alextstone]

18 minutes ago, David_H said:

Thanks for sharing this. Maintenance induced failure is very real.

Could this have been caught during the post maintenance run-up by the shop? Did they do one?

A run up was done by him, then by me twice and I took two flights as well before this one, each with thorough preflight inspections.  

[alextstone]

4 minutes ago, Yetti said:

contributing factors on the RCA would be "need to install an engine monitor before a big trip"   Work practices by the shop/mechanic.   I don't trust the mechanical condition of the plane after big things till after a RTS flight and 5-10 hours of flight time.

@Yetti at what point should one consider an aircraft safe for a “long flight”?  As often as I seem to have my airplane in for maintenance, i need a strategy that is both safe and allows me to use my plane for its intended purpose.  I made two post maintenance local flights before leaving for the trip....I’m not defending myself though.  In retrospect, I should have removed the top cowling to inspect after the local flights...that to me was the bigger mistake than an additional flight or longer timeframe...do you agree?

[mike_elliott]

The use of torque seal along with proper practices (do not put a nut on a bolt without torquing it) will go a long way to mitigate the loose fastener maintenance caused issues. 

[Shadrach]

1 hour ago, mike_elliott said:

The use of torque seal along with proper practices (do not put a nut on a bolt without torquing it) will go a long way to mitigate the loose fastener maintenance caused issues. 

I too am a proponent of torque seal.  You must be quite a bit stronger than I am...I don’t think I could time a mag with the nuts torqued!

 

Edited May 10, 2019 by Shadrach

[Yetti]

3 hours ago, alextstone said:

@Yetti at what point should one consider an aircraft safe for a “long flight”?  As often as I seem to have my airplane in for maintenance, i need a strategy that is both safe and allows me to use my plane for its intended purpose.  I made two post maintenance local flights before leaving for the trip....I’m not defending myself though.  In retrospect, I should have removed the top cowling to inspect after the local flights...that to me was the bigger mistake than an additional flight or longer timeframe...do you agree?

So.   I just had the fuel servo overhauled at annual.

For me.  I trust the person doing the work since I did the majority under the IAs direct supervision.

Before cowling I spend about 30 minutes per side looking a grabbing, and touching things.   Good way to catch wires flopping.   or finger tight fuel lines.

What I don't know is how good the overhauler is.

Spent a fair amount of time running the engine adjusting the idle and mixture adjustment so I have several starts and stops and looking and triple checking fuel lines.

Got sign off and  I buttoned up.    Did two fast taxis.  

Based on performance decided to take it up to 8000 feet directly over the airport.

No hicups.

Come back and decowl and check for leaks.

I have two or three short flights and I am considering put it into the good to go.

This the problem with people who think pulling a cylinder for inspection is a good idea.   I say no because it puts the plane in the danger zone.

Bicycles are bit simpler, but I do the same for them.  You don't want things coming loose at 20 MPH.

 

 

[FlyBoyM20J]

8 minutes ago, Yetti said:

So.   I just had the fuel servo overhauled at annual.

For me.  I trust the person doing the work since I did the majority under the IAs direct supervision.

Before cowling I spend about 30 minutes per side looking a grabbing, and touching things.   Good way to catch wires flopping.   or finger tight fuel lines.

What I don't know is how good the overhauler is.

Spent a fair amount of time running the engine adjusting the idle and mixture adjustment so I have several starts and stops and looking and triple checking fuel lines.

Got sign off and  I buttoned up.    Did two fast taxis.  

Based on performance decided to take it up to 8000 feet directly over the airport.

No hicups.

Come back and decowl and check for leaks.

I have two or three short flights and I am considering put it into the good to go.

This the problem with people who think pulling a cylinder for inspection is a good idea.   I say no because it puts the plane in the danger zone.

Bicycles are bit simpler, but I do the same for them.  You don't want things coming loose at 20 MPH.

 

 

I'm reading this carefully, thanks!

Lucky for me, I do most of the work on my plane alongside my A&P, so I am going to be directly involved when we re-install the cylinder we pulled due to the bent pushrod (other thread) last week.  I do trust my mechanics but everyone makes mistakes and I prefer to double-check things in person.

[tigers2007]

If I recall correctly, I believe U of M's Survival Flight calculates like three hours maintenance for every flight hour (or was it 2-to-1?). That might have changed when they leased newer helo's. For the five minutes it takes to pull the side panels, its a small sacrifice to make. Heck, I found a completely disconnected prop control cable... 

[Yetti]

37 minutes ago, FlyBoyM20J said:

I'm reading this carefully, thanks!

Lucky for me, I do most of the work on my plane alongside my A&P, so I am going to be directly involved when we re-install the cylinder we pulled due to the bent pushrod (other thread) last week.  I do trust my mechanics but everyone makes mistakes and I prefer to double-check things in person.

Think of how many mistakes you make each flight, well I am probably only the one pilot that makes mistakes flying.   same thing

[steingar]

One of the very few things I dislike about my Mooney is it takes forever to remove the cowlings and even longer to put them back on.  Hence the engine doesn't get the kind of inspection I like prior to flight.  Hence I take off and hope for the best.  Heck, it's worked so far...

[Yetti]

7 minutes ago, steingar said:

One of the very few things I dislike about my Mooney is it takes forever to remove the cowlings and even longer to put them back on.  Hence the engine doesn't get the kind of inspection I like prior to flight.  Hence I take off and hope for the best.  Heck, it's worked so far...

The F with the bottom cheek plates and cam locks is wonderful for this.   Maybe you need a new used cowl :-)   See how easy it is me to spend others money.

[tigers2007]

I bought a Milwaukee screwdriver and it only takes two minutes to pull each side panel.  I really wish there was an easy way to have it converted to Camloc^® fasteners. 

[steingar]

44 minutes ago, tigers2007 said:

I bought a Milwaukee screwdriver and it only takes two minutes to pull each side panel.  I really wish there was an easy way to have it converted to Camloc^® fasteners. 

Even with my drill it takes awhile to decowl, and longer to put everything back together (screws never seem to fit the way they came out...).  If I did it every flight I'd never fly.

[Yetti]

2 hours ago, tigers2007 said:

If I recall correctly, I believe U of M's Survival Flight calculates like three hours maintenance for every flight hour (or was it 2-to-1?). That might have changed when they leased newer helo's. For the five minutes it takes to pull the side panels, its a small sacrifice to make. Heck, I found a completely disconnected prop control cable... 

A helicopter - A million parts trying to shake itself apart.

[steingar]

1 minute ago, Yetti said:

A helicopter - A million parts trying to shake itself apart.

A thousand parts rapidly circling an oil leak.

[RobertGary1]

Personally I don't let people wrench on my plane without me there but if I did I'd do a complete inspection. Two eyes are better than one.

 

-Robert

[Skates97]

1 hour ago, tigers2007 said:

I bought a Milwaukee screwdriver and it only takes two minutes to pull each side panel.  I really wish there was an easy way to have it converted to Camloc^® fasteners. 

I'm glad I have a 65 instead of 64D, it has the Camlocs and easy to take the cheeks off. I still don't pull them on every pre-flight, but I do take a flashlight and shine it down in both the oil and battery access doors to look around for leaks or odd looking stuff everytime.

[neilpilot]

34 minutes ago, RobertGary1 said:

Two eyes are better than one.

All but one of the A&P's I've used over the years have had 2 eyes.

[Skates97]

Just now, neilpilot said:

All but one of the A&P's I've used over the years have had 2 eyes.

Ok, completely off topic, but a funny story.

My wife and I met online through match.com. (How better to meet someone you hope is compatible when you both work, you have 4 kids and she has 3?) Anyway, when I tell people how I got so lucky meeting her I would say there were only three guys online for her to choose from, one was in his 70's (this was when I was 36 and she was 40 so 70's was a touch old), one only had one eye, and then there was me.

I would often tell that joke when people ask how we met. We had been married about 5-6 years and were at dinner at a vendor incentive trip and sitting with 3 other couples. Everyone was introducing themselves and telling a little something about themselves. I told my old joke about how we met and a guy across the table said "What's wrong with one eye?" Yep, he had a glass eye...