N6018X - Anyone know more about this accident?

[corn_flake]

Hi all, 

For some weird reasons, when I'm not flying, I'm reading accident reports.    I think the original goal was to learn from other's mistakes.  But, it does rattle me a bit....  In any particular case, this one hits close to home.  A Mooney based at Shafter, CA.   

Any one know more info about it?  Was the pilot a member of this forum? 

Based on the FAA registery, the plane was gear-up in 2006.  It was "repaired" and went thought several ownership change without much flight time.  In 2011, the accident pilot acquire the Mooney.  Less than 180 hours after the gear-up, the engine self-destructed in-flight.  The cause of the ticking time-bomb - a non-standard shim installed on the propeller flange to correct a bent crank.  No entry for the non-standard shim in the log book.  It could have been the repair that done was after the gear-up.  

Reading the accident report sends a chill down my spine.  When I was shopping for my Mooney two years ago, I can recall communicating with a dealer about a prospective Mooney.  The Mooney had a recent gear-up and was "repaired" without an overhaul.  The dealer was trying to convince me that overhaul was not necessary and the plane was a good buy.   I end up walking away from the deal.  But, I often do wonder if another Mooney pilot's life may be at risk as I write this post.  

Here are the links to the accident report and registration history for the N6018X.  For this accident, the pilot lost his wife and two kids lost their mother.  

http://www.kathrynsreport.com/2013/03/mooney-m20-woman-dead-husband-and-son.html

https://flightaware.com/resources/registration/N6018X

[carusoam]

Flake,

The whole purpose of the PPI is to determine if the plane is AW or not…  the amount you pay for the PPI is dependent on the amount you want to know…

Some people want to buy planes that have NDH… the PPI will be looking for signs of damage history…

The basic test to see how bent the flange is… measures the run-out… how much the flange surface moves when rotated…. There is a spec for that.

If somebody was putting a spacer on the flange because it’s run-out was too much…. You would have to ask a real mechanic if that is an improved method of compliance…

 

Resources around here…

We have a prop guy… Cody… Who can tell you if using a spacer to level the prop is acceptable…

We also have Alan… who has posted pics of measuring the run-out of a prop flange, and has given the spec that goes with it… (earlier today)

 

The forces on a prop are in the thousands of pounds… any improper parts used… are reasons to fail a PPI…

 

As you would expect…. PPIs for ancient planes can be more expensive than on newer planes… with fewer hours…

 

There are many ways to tip the balance of safety in your direction…

Select a plane that fits your budget…

Buy one from somebody that you know who has owned for a long time already…

Buy one that has the least damage history possible…

Pay to have the plane inspected… as you require.  Not what somebody else requires…

Read the logs… who made what repairs… known Mooney shops, known mechanics, or unknown… non-Mooney mechanic…

 

Like anything else… you still have to plan on having an engine out event yourself… every take-off, every airport…

Its the nature of  the beast…

You get extra credit for reading accident reports… but, look for the positive outcomes to learn how the recovery was made…

Focus on the Mooney related ones…

There are so many accidents available to read about… you will need a therapist to get over the nightmares…  

PP thoughts  only, not a therapist…

Best regards,

-a-

 

 

[kerry]

I remember when this accident occurred. Besides the engine going out my take a way's were the likely hood of the passenger surviving the crash if shoulder harnesses were present.  Also I would have kept my gear retracted when ditching in the desert.

[EricJ]

2 hours ago, kerry said:

I remember when this accident occurred. Besides the engine going out my take a way's were the likely hood of the passenger surviving the crash if shoulder harnesses were present.  Also I would have kept my gear retracted when ditching in the desert.

Shoulder belts are life savers for front-seat occupants.   

[A64Pilot]

I didn’t read the accident report, but there are runout limits for the crankshaft flange if Lycoming, they can be found here

https://www.lycoming.com/sites/default/files/SSP-1776-5 Table of Limits - Complete.pdf

I attached the applicable page, but new run out limit is .002 inches and i’m service .005 so anything above .005 means the crankshaft is scrap.

 

 

[A64Pilot]

A PPI or anAnnual would not have discovered this shim, only prop removal would have in my opinion, it may not have been visible but maybe if it was thick enough?

Whoever singed off the installation of the prop may be looking at prison time if it can be proved beyond a reasonable doubt that’s when the shim came into being, again, another opinion. Purpose of the shim was to restore blade track and hide the bent crankshaft, presence of the shim proves the mechanic knew the crank was bent, again an opinion

I went back and scanned the report

Edited October 18, 2021 by A64Pilot

[carusoam]

Reading the Kathryn’s report is like reading a murder mystery…. A who dunnit, With several possible characters…

Keep in mind the ground strike rules have changed… probably a few years after this accident…

The plane had…

• a GU landing
• a repair of the airframe
• a new prop
• some unlogged repair activity related to the engine
• The crank shaft was bent, a lot.
• a wedge spacer was manufactured to shim the prop into alignment, not in accordance with any particular rules.
• Building the fancy shim took knowledge of mechanical skill…
• the fancy shim had no documentation, didn’t come from an airplane part supplier…

The fatal accident proved…

• Flying with a bent crankshaft burns up the Bearings inside the engine…
• While burning up the bearings the oil gets destroyed…
• Destroying the oil seized the engine

The Kathryn’s report mentioned three people…

1) Mechanic

2) IA

3) Owner

4) Somebody was aware this engine should not be in service after the GU landing.  

• Ground strike, gets a runout measurement…  this one had a huge run-out.
• today, the engine gets torn down and internal parts get measured…

5) Somebody knowledgable enough to build a spacer to take out one effect of a bent shaft, built a technical non-aviation part… but forgot/didn’t know to take care of the other effect of a bent prop… lubrication system failure…

6) The owner of the plane was an owner of a metal company… and a member of a church…

 

Its highly unlikely that all of the facts have been covered correctly by reading the Kathryn’s report… 

 

Follow-up questions…

1) If your prop wobbles do you have a shim built to match the run-out yourself?

2) Did the shim improve any of the vibration that had to come with the bent shaft?

 

Lycoming and Continental have both updated their procedures for repair of their engines after a ground strike that include defining what a ground strike is…

Following current ground strike rules… this engine would not have been flying…

Following the old ground strike rules… this engine would not have been flying…

 

Kathryn said somebody knowingly put an unapproved part where it didn’t belong… kind of making an experimental Mooney… but, who-dunnit?

Proof that following the rules for prop strikes is a really good idea…. 
 

Best regards,

-a-