[TGresham]

Kyle:

I can offer only my experiences, but I have come to think of the modern engine monitor as an extremely important item in the panel.

It does a lot more than most pilots know, including those who already have one.

An example of how it saves money, and time. (Time is the more scarce resource.)

I was flying back to Louisiana and was making a fuel stop in Louisville, KY. When I started the descent, I felt a very slight rumble in the seat of my pants. The passenger did not notice it.

Without the engine monitor, and the knowledge of how to use it, I might have shrugged it off and pressed on, or I would have to tell the mechanic "it's a funny rumble that I can kind of feel, but I don't know where it's coming from."

Instead, when I landed, I told the mechanic that the spark plug in the number three cylinder -- the plug running off the right mag -- was going bad. I had him replace it while we had lunch, and then we headed out.

The plug was not dead -- yet -- but it was intermittent.

How many hours could have been spent troubleshooting that? I dunno, but I paid for a spark plug and an hour of shop time and suffered zero delay.

On another plane, wiithout an engine monitor, I had an "event" which trashed three cylinders. (For the sake of clarity, I was running ROP at the time.) All I felt was a rumble, but I couldn't diagnose it. Not a big deal, just a vibration. If I had been able to glance at a monitor, I would have known it was serious and could have shut that one down, or landed.

Cost? Three weeks grounded, and about $4,000. I was actually lucky. It could have resulted in the loss of the engine.

As always, it depends on the needs, the use, and the disposition of the pilot/owner. I use my planes for transporation, over mountains, at night, in solid IFR. (Not all three at the same time, though!) Downtime is a really big deal. For me, the engine monitor, and the knowledge of how to get the most out of it, gives me additional comfort, and it saves me money and time.

For others, that equation might not be the same.