Engine failure just after take-off, M20B

[nm1]

My father just purchased an M20B 3 weeks ago, it had been running great and was just 100 hours since overhaul.

Yesterday my parents took off from a 3500 ft strip with trees at the end. My dad rotated around 65, was keeping the speed around 80 during the initial climb to aid in bringing the gear up. Just as he was reaching for the gear handle at around 100 ft, my mother says she heard a loud bang and then there was an abrupt loss of all thrust.

My dad lowered the nose immediately, and had just enough energy at the end to round it out and prevent the nose from hitting first. Hard landing, but no prop strike or damage. With maximum braking, they were just able to stop the aircraft before the end.

They taxied clear of the runway, and the engine was still running. My dad said the engine responded normally on the taxi back to the hangar. He and my brother are busy tearing it down to figure out what went wrong. His gut reaction is that it was fuel contamination of some kind, but I'm not so sure.

They are very fortunate; 2 people have died in similar circumstances at that airport in the last 4 months.

Anybody have any thoughts? Are there any things common to Mooneys that could have contributed to this sudden loss of thrust?

[Shadrach]

What kind of a "bang" are we talking about, combustion or mechanical? Something went horribly wrong, and I would be afraid of it until a definitive cause has been found.  Bad gas should be easy enough to confirm or eliminate by pulling the sump. I'd also carefully inspect the mags for problems that could cause timing issues.

[RocketAviator]

I can not contribute any useful knowledge to your request but I would be very interested in knowing what they learn..

I would say Prayers of Thanks are in order!!

[mikesalman]

I'm a new pilot so forgive me if I'm wrong, but could it be possible the mixture was not returned to full rich for takeoff? I know in my 24 hours in my M20F while taxing from the hanger to the run up I sometimes lean too much and the engine starts making funny noises.

[DAVIDWH]

 Mike Busch (Av-Web) discusses at length, what he calls, "infant mortality" rate after overhaul.

 

Amost all engine faiures after overhaul happen within the first 400 hours with a preponderance

 

of these engine failures within the first 100 hours. Your father is flying that engine at a very precarious time

 

in the engines life.

 

So glad all is well, please keep us posted.

[Chris 68 M20C Ranger]

I had something like this happen to me in my 68M20C Ranger it was due to forgetting to set the mixture to rich there was a bang of detonation or somethign like that.

[Sauduster]

Glad to here that they are OK. I'm pretty sure that I know your father (BN). I am sure that his years of experience and piloting skills played a major role in the successful outcome.

[Shadrach]

I am skeptical that one could here detonation over the the prop and exhaust noise, but maybe with Bose headsets. That being said unless there is a significant ignition timing issue, you'd be hard pressed to make an Lycoming IO360 detonate under even the most ham fisted throttle and mixture settings. The FAA has codified detonation margins for certification and it's highly unlikely that anyone here could exceed those margins, even when trying. Also, I'd venture a guess that almost everyone here that ground leans has forgotten to enrichen for take off. This is not something that you don't notice until after rotation as the engine will protest immediately.

What about the throttle vernier?

One of the stupider things I've done caused a similar situation (sans the "bang"). I was going into a pretty short (~1800ft) down hill strip on a gusty day. I loosened the throttle vernier so I could jockey the throttle a bit to maintain a stable approach. After landing, I never bothered to tighten the vernier back up for the take off later in the day. After rotation, I retracted the gear and the hit the trim wheel. I immediatly wondered why airspeed, ROC and Climb angle were all so low... In the seconds it took me to operate the Johnson bar and retrim, the throttle had backed out 50%...Not enough to take the prop governor off line, so everything sounded normal, but my Mooney was performing like a C150 in July with an obese instructor in the right seat...Valuable lesson learned.

[nm1]

Sauduster, you are right.  You know him, and his 54 years of experience saved them both.  I am so thankful for the successful outcome.

 

Shadrach, the bang was described by my mother as a "backfire" sound.  I don't think the problem was mechanical.  They both said runup was fine and unremarkable.

 

Regarding leaning during taxi, my dad didn't. 

 

Thanks to all for showing concern for my folks.  I was, and still am, a bit shaken up about it;  I just hope he and my brother are able to trace the problem down to something certain.  I'll update as I am updated.

[pinerunner]

Neffmeister

 

I'm glad it turned out well in the end. If it doesn't turn out to be "infant mortality" as DAVIDWH discussed my first guess would be that the throttle slipped out quickly leading to the backfire. I've had my throttle slip out slowly back when I first got my M20E usually during takeoff when I was busy with the gear. Lucky for me it was the first thing I thought of and just pushed it back in. There's a whole thread on it and I'm beginning to think its common. 

 

Dave

[flyboy0681]

 

They are very fortunate; 2 people have died in similar circumstances at that airport in the last 4 months.

 

 

 

Hopefully he bought a lottery ticket later that day.

[DaV8or]

Here's my $.02 internet advice-

 

I seriously doubt you had a detonation event. There is no bang involved until total engine failure. If you had an extended detonation event that caused engine failure, or a pre ignition event, your engine wouldn't running fine now. The bang probably was a back fire and this is caused by unburned fuel getting into the exhaust system and then getting ignited in there. What causes the fuel to get there is either lack of spark ignition, or a stuck valve. Unfortunately, it is common that the valves on our engines sometimes get stuck.

 

I personally think a stuck valve is the most likely, but unless you can prove it, you have to check all of the ignition out too. After that, you might want to do an inspection of the muffler and exhaust system for damage and leaks. Sadly, sticking valves can unstick themselves and make it difficult to identify. Starting place would be compression check, pull the plugs and inspect them and bore scope if you have it. Try to figure out which cylinder is to blame. It's so much easier when the engine runs like crap.

[chrisk]

Dave, I think you have it with your stuck valve theory.

[bnicolette]

Thank goodness they're okay!! Is there an engine monitor installed? This is precisely where it would come in handy. It would certainly show if it was indeed a stuck valve.

[jetdriven]

This has me thinking. I recently had a mag fail, and the subsequent runup, when switched to the failed mag, made several violent backfires and the engine spun down. The mag was certainly dead, so the fuel was lighting off in the exhaust. It was quite loud and alarming, and I was certain I blew something up.

 

So your issue, perhaps the ignition switch is faulty and allowed both mags to ground out. Thats the only common point for the two mags to ground out and shut off. There was an article I read somwhere that the ignition switch's rotary contacts wear out.  Perhaps running the engine at 1500 RPM and putting a lot of pressure on the key in all directions, or the instrument panel might get it to duplicate the mag grounding, if this is the problem.