Run-up on taxi?

Some of the comments here make me wonder how other guys fly. No matter, here's how I fly.
Mag drops at 18 and 19 seconds in. No, I don't return to both in between the L-R checks. Prop cycling is at 24 seconds. You can see the acceleration that comes with doing it on the roll. No big deal. Carb heat is checked at 29 seconds. All in all the rolling run-up saves the prop from gravel dings and the carb from sucking up dust during the carb heat check. Controls were verified while warming after start-up. Flaps are set when lined up. Standard operating procedure on a gravel strip. In this case a rather narrow one. The strip is approx 1000' long and the windsock is 600' downfield in this video. Lots of room. Pardon the vibration but this mount wasn't dialed in at the time.

 
Stewartb said:
No, I don't return to both in between the L-R checks.
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I return to both only to make sure my mind isn't playing tricks on me and there's a drop. It's not so much a function check so much as a grounding check.
 
Grounding check? That requires you select off to assure the mags are disabled. I don't want to make that mistake during a rolling run-up. Inducing a big backfire isn't what I want right before I launch.
 
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mkosmo said:
I return to both only to make sure my mind isn't playing tricks on me and there's a drop. It's not so much a function check so much as a grounding check.
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Which proves nothing with regard to grounding. Just because you have a drop in L and R doesn't mean you have grounded mags in OFF.
 
It grounds each individually assuming that your switch isn't hosed. I don't know about you, but I've certainly found a proven p lead that way.
 
While it will let you know if you have a problem, the fast that you do get a drop doesn't prove you don't. I had a switch that would unground a mag when you removed the key even though you could get drops on L and R and even OFF. Aircraft key mag switches are cheesy cabinet locks. Lots of slop. There was an AD on certain bendix switches back in the day, but that's not the limit of the problem. We found out mine was defective when the mechanic was attempting to time the mags and managed to zap herself on a supposedly grounded mag.
 
The old timers at my airport say to do your runups at 100'AGL on the climbout to save your prop from gravel dings......

:p
(yes, of course they're joking... in case your sarcasm detector is broken)
 
I was taught to do a full stop runup the first flight of the day and from then on if you're flying all day with a few stops it's pilot's discretion but not necessary. If the plane re-starts fine, runs fine, sounds fine, all warmed up and in the green, ... go. :cool:

edit in: I try to check mags before final shutdown, but I don't always remember. ☺ "don't put a sick horse to bed."
 
I always stop for runups except on slippery ice or snow (where it's impossible or dangerous).
The trickiest ones are when on ice or snow that seems stable but you start creeping forward (or sideways) on the runup, while head down looking at stuff inside. Always look partially outside on runup!
I haven't done any seaplaning in recent years, but of course in that case it's always done on the go.
 
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