Magneto Failure

On Wednesday 2nd October we witnessed the initial troubles and susequent failure of our single Slick magneto; thankfully whilst on the ground.

My father had flown the RV to Kemble to get fuel and meet myself, wife and puppy as we were introducing her (the puppy!) to aeroplane noises for the first time.

Dad and I were going to fly back home as it was my only opportunity to fly that week. After start I noticed a farily poorly running left mag during the 1,000 rpm check. I had felt similar before when we’ve had a bad plug. We taxied out and I anticipated doing some leaning off to try and clean things up inside the cylinder.

As the engine settled at the usual 1,800 I tested the right mag (this is infact an LSI Plasma 1 electronic ignition unit), which showed a drop of around 40rpm (it is usually 70 range).

Next, it was time to try the right mag and I expected a little shudder and RPM fluctuation if we did have a plug that wasn’t firing healthily.


What we were treated to was a cocophany of misfires which sounded more like the start of a gun battle than a Lycoming O-320. I immediately threw the switch back to BOTH and pulled the power back to 1,000 before spending the next 5 minutes trouble shooting the problem. Sometimes it would misfire terribly, other times just run very rough. There was also a noticable RPM flucutation of around 20-30 whilst on BOTH , which I might normally have expected in very blustry conditions, but we were facing a fairly steady <8kt breeze.

Not satisfied, we taxied back to parking.

T+2 hours

Fast forward a couple of hours and we were parked on the grass at Kemble with our ever-helpful local inspector Steve Evans who, fortunately, happened to be a few minutes away at Oaksey Park. I had tried in vein to secure hangar space for the night to take the pressure off leaving the RV out in the rain; but all the inns were full. We visually inspected all plugs and confirmed nothing out of the ordinary and then ran the engine. Sure enough, upon selecting the LEFT mag, the engine died instantly.

Our inspector was pretty much convinced that the mag was at fault and should be looked at, so we helped him with the removal (its a very tight fit) and I called Pete Montgomery at Pure Aviation who completed the 500hr inspection and had replaced a few old parts just 6 months before.

T+4 hours

Thanks to Pete’s excellent service, we drove the mag 20 miles to his house and he promised a free inspection to determine if there was any failure.

T+21 hours

By 8:30am on Thursday morning I woke to an email from Pete with a succinct explanation that the coil had failed completely, despite being perfectly healthy just 6 months ago. All other parts that he had serviced/replaced were also in fine fettle. Pete gave me a few options and we elected to have the coil replaced same-day, rather than go for a new mag which would be in by the following day.

T+24 hours

I was now back at home, with a repaired mag, calling as many companies as I could to find somebody able to do a same-day call out job. Three leads were promising. This soon dropped to one. Steve’s phone wasn’t connecting so I was recommended another local, RV flying, inspector by Ed Hicks (Flyer Magazine’s Editor), via a mutual friend. This inspector, Phil Hall said he would be happy to drop by and look at it later in the afternoon. I just had to find someone to fit it!

T+27.5 hours

At 1430hrs I recevied a call back from the Classic Aeroplane Company at Oaksey Park, saying they could have two engineers with me in 30 minutes if I still needed them. The very helpful Jon and Darren got to work and had the mag fitted and timed less than an hour later. When it became aparent that they were almost finished I rang Phil, who was miraculously just 5 minutes away.

After a successful engine run (the anxiety of turning that keyswitch to LEFT was very real), we replaced the cowl and I managed to depart Kemble in a lessening crosswind and developing rain.

By T+29.5 hours I was back in the hangar at base, having done my best to outrun the approaching rain at 150kts. Once the aircraft was put to bed I couldn’t quite believe that in just over a day we had suffered a mag failure, had it removed, driven across the county twice to drop it off and collect it, then met three total strangers who worked professionally in cold and windy conditions to fit it to our aircraft. Now, the engineers were doing their job (very well and with smiles on their faces), but the spirit of the Light Aircraft Association was felt in abundance as the very helpful Phil had taken time out of a busy day to come and ‘rescue’ us before we were hit by the tail of the Hurricane formerly known as Lorenzo.

The two lessons to this story are:

1. When you find good people, save their numbers.

2. Be assertive! Had we found a hangar space we could easily have waited days for a Kemble engineer to become available and the whole process could have dragged on for days.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s