Slick Service Bulletin
 

Is anyone aware of Slick SB1-98A requiring inspection of the impulse coupling(s) on any 540-XXX5, IO-540-D4A5 as an example? Has anyone had a problem with the rivets on the 5th order counterweight engines?

The engines effected:

The following Lycoming O-540 and IO-540 engines configured with fifth order counterweights:
O-540 A1D5, B2B5, B2C5, E4B5, E4C5, G1A5, G2A5, H2A5
IO-540 AC1A5, C1B5, D4A5, K1A5, K1B5, K1E5, K1G5, K1K5, L1C5, M1C5 AEIO-540 L1B5
TIO-540 AH1A, AJ1A, W2A

The 250 hour impulse coupling inspection must be performed each time the magneto accumulates either 250 hours of operation from the time of the last inspection, field overhaul, or since new or factory rebuilt. See magneto maintenance and overhaul manuals L-1037 or L-1363 for overhaul instructions.

I got this info from the Slick booth at AirVenture

Thanks Gerry

I hope everyone is aware of this Service Bulletin with engines referred to in the
SB.
I have inspected mine at the 250hr interval and found the impulse coupling specs well within tolerance.
You'll need the puller to get the coupling off.

https://goo.gl/photos/GzakX4AQLPjf7cfEA

https://goo.gl/photos/Ucq6h5UVu9NzZbjQA

The standard Vans setup for at least a few years now uses Retard Mags, so it may be only a small set of 10s with Impulse mags that need to do this SB.

I would not ignore if you have impulse couplings on these -5 engines
 

I attended a forum at Oshkosh last month that was put on by Slick / Champion and this was one of many topics presented. The speaker conveyed that Slick was very concerned about this failure mode on these dash five 540's and they are encouraging the FAA to decrease the inspection frequency and I believe issue an AD. I'm not trying to be an alarmist, but he said this was killing people and they would rather see a competitor's mags installed on an engine than see this SB ignored. If I recall correctly he went over three fatal accidents where impulse coupling rivets had failed and the fly weights had taken out the accessory case gears and eventually the whole engine. Perhaps others on VAF also attended and can confirm if my memory is correct.

Slick service bulletin
 

Anyone have a copy of the slick service bulletin Slick SB1-98A?
I see a 98B but no 98A.

I attended the same workshop and when I learned it didn't involve my setup, I relaxed a bit. I was impressed on his stance on wanting to address and rectify it, and totally floored when he suggested a competitors product.

Another thread on this topic:

http://www.vansairforce.com/communit...t=Io-540+slick