Strangest failure

[N201MKTurbo]

I had a strange engine failure about ten years ago in my M20F.

 

I was flying along over some very inhospitable terrain when I heard a loud bang in my engine compartment. The engine continued to run and all indications were OK. I considered continuing on to my destination for about 30 seconds and then wisely decided to land and check it out. There was an airport about five miles away, so I landed there. When I got out the right side of the plane was soaked with oil, there was 2 quarts left in the engine.

 

What had happened was the fan on the alternator flew apart and one half of it hit the oil cooler and made a small hole in it. It is amazing how much oil will come out of a small hole at 60 PSI.

 

 

I was just wondering about any other stories about odd failures like this.

[Marauder]

Good topic. Knock on wood, mine was a failed exhaust stud. After the stud failed, the other nut vibrated off. The engine analyzer showed the drop off of the exhaust temp but still showed cylinder temp. It sounded like a Harley without an exhaust in the plane. And like your situation, I was dealing with IMC. Once I figured out whati thought was going on, the next thing thou my head was the fear of fire.

[BigTex]

I was about to post something similar but I had an "event" occur last weekend.  I flew up to a local airport to practice landings.  I flew there, landed, taxied back and took off.  After climbing out to about 3,000', I pulled back the throttle to configure for cruise flight and the engine started to run very rough.  I increased the throttle and the engine smoothed out.  It ran fine until I pulled the power to land.  On the ground while taxiing to my hangar it ran extremely rough.

 

After shutting down, I looked around and didn't see anything obvious like oil.  So I downloaded the data from my EDM-700.  Below is the link to my data from the flight.

 

https://www.savvyanalysis.com/flight/211461/31c29c48-6159-46f0-9e70-14df5aaf2786

 

The event occurred at the 57:18 mark.  I've already identified the issue.  Before I explain what occurred, does anyone have any guesses based on this data?

[larryb]

The event occurred at the 57:18 mark.  I've already identified the issue.  Before I explain what occurred, does anyone have any guesses based on this data?

 

Induction leak on #1?

[chrisk]

#1 is not working properly.  May be overly lean, possibly indicated by increase in EGT.  Partially obstructed injector?    Leak in intake system as previously mentioned?

[larryb]

  Partially obstructed injector?   

Aircraft is C model (from signature) so no injectors.

[bnicolette]

The event occurred at the 57:18 mark.  I've already identified the issue.  Before I explain what occurred, does anyone have any guesses based on this data?

 

Fouled plug?    I generally get a 50 degree rise during my mag check.

 

Bad Exhaust Valve?

 

I give up!  Looking forward to the correct answer though.  

[BigTex]

This will likely give it away but the manifold gauge quit working at around the same time.

[Alan Fox]

I had the intake tube bolts come loose on one runner , Causing High EGT on one cyl, and backfiring running rough at low power settings.... 

[N201MKTurbo]

Manifold pressure line broke

[BigTex]

What happen was that the manifold line going into the #1 cylinder came loose. Reconnected it and it now purrs like a kitten. I couple of months ago I had my A&P fix my manifold gauge. What I suspect what happened was that the connection was only finger tightened and over the last couple of months, it worked itself loose. What's ironic is that last week I watched Mike Busch's webinar on Maintenance Induced Failures and what a large percentages of crashes was tied back to main tench errors. A webinar worth watching.

[M016576]

Plugged injector.

Edit- oops! Didn't notice it was a C. Blown cylinder?

[jimosborn]

Guys and Gals:  Don't miss the HUGE  significance of what happened immediately afterwards. 

 

Per Gary's JPI download, at time 57:18  #1 EGT was running 1307^o.  After the MAP tube separated, EGT peaked at 1467^o; a full 160^o hotter than cruise, which means the engine previously had been operating at least 160^o ROP.  Then, less than one minute later @ 58:48, notice that EGT dropped 54^o below peak; meaning it was then running 54^o lean of peak (LOP)....... from that point forward, and with no apparent change in power setting until descending, CHTs steadily shed nearly 100^o.  Again... with NO power changes beyond un-commanded leaning caused by a blown MAP line that's piped into the induction system!

 

Now if there be skeptics regarding the value of LOP in terms of better engine health (cooler, cleaner, leaner), then one need look no further than this graphical evidence for a favorable reading, brought about in this case by mechanical happenstance.
 

Cheers folks.

[WardHolbrook]

I like this thread. It shows that not all serious power losses are caused by catastrophic engine failures. An engine can be perfectly good and mechanically sound, but for various and sundry reasons not be able to produced its rated power. The end result is the same however. Over the years, I've had about a dozen power failures in everything from a Cessna 172 to a Gulfstream Bizjet. Out of those, only three - a Mooney M20C, Cessna 411 and a Lear 35 - involved the classic catastrophic failure scenario. The other nine had various causes from a magneto switch failure to a broken oil line to a bleed air leak. Regardless of the reason, loss of power is a loss of power.