when to run up and check the prop

I fly some high performance, complex singles like Saratogas, Lances, C182RG,
C206, and the like. Typical flying days have multiple hops while seeing
customers. On one hand I know pilots who say that you should do a full run
up and prop check before every take off, because the checklist says to. On
the other hand, I know pilots, mostly owners of similar aircraft, who only
do a full runup and prop check on the first flight of the day. Their
rationale is that doing it four or five times a day is unnecessarily hard on
the engine and when its been flown in the last few hours there's no need to
cycle the prop more. They argue if there's a new problem during the day
like a mag, its easy to detect upon first throttle up as you take off. You
would hear and feel the engine roughness and see its not developing full
power.

Are there any good arguments out there based in science and fact and not old
wives tales to support only doing a run up and prop check on the first
flight of the day ? I'm talking about a situation where you're flying
multiple flights a day and the engine never completely cools off.

I'd only run up and check the prop when the engine's not running. You can
get hurt otherwise :-)

--
Bob (Chief Pilot, White Knuckle Airways)

Are there any good arguments out there based in science and fact and not
old
wives tales to support only doing a run up and prop check on the first
flight of the day ?

How about lowering the risk of an engine failure in the air by inducing any
impending failures while on the ground?

Bob Chilcoat wrote:
I'd only run up and check the prop when the engine's not running.
You can
get hurt otherwise :-)

--
Bob (Chief Pilot, White Knuckle Airways)

sissy

\
dan

Friendly Skies wrote:
snip
Their
rationale is that doing it four or five times a day is unnecessarily
hard on
the engine and when its been flown in the last few hours there's no
need to
cycle the prop more.

I don't see why a runup or a short prop cycle should be unnecessarily
hard on the engine. If they're stopping that many times a day, they'll
get the procedure down to a few seconds.

In the backcountry, where there is often no place to runup without
sucking rocks into the prop, we often do the mag check early in the
takeoff roll. It's an extra step during a critical phase, but I
always feel more comfortable rolling towards the trees and rocks at the
end of the runway when I know all of the plugs are firing on time.

John Galban=====N4BQ (PA28-180)

Bob Chilcoat wrote:
I'd only run up and check the prop when the engine's not running.
You can
get hurt otherwise :-)

For some corny reason, this made me burst out laughing at work. How
embarassing.

Charles.
-N8385U

"Friendly Skies" wrote in message
...
[...] Their
rationale is that doing it four or five times a day is unnecessarily hard
on
the engine and when its been flown in the last few hours there's no need
to
cycle the prop more.

They may say that as many times as they wish. Without proof, it's an empty
statement.

They argue if there's a new problem during the day
like a mag, its easy to detect upon first throttle up as you take off.
You
would hear and feel the engine roughness and see its not developing full
power.

That argument holds as much validity for the first flight of the day as for
the Nth. Why bother doing a runup at all then?

Pete

"Friendly Skies" wrote in message
...
I fly some high performance, complex singles like Saratogas, Lances,
C182RG,
C206, and the like. Typical flying days have multiple hops while seeing
customers. On one hand I know pilots who say that you should do a full
run
up and prop check before every take off, because the checklist says to.
On
the other hand, I know pilots, mostly owners of similar aircraft, who only
do a full runup and prop check on the first flight of the day. Their
rationale is that doing it four or five times a day is unnecessarily hard
on
the engine and when its been flown in the last few hours there's no need
to
cycle the prop more. They argue if there's a new problem during the day
like a mag, its easy to detect upon first throttle up as you take off.
You
would hear and feel the engine roughness and see its not developing full
power.

Are there any good arguments out there based in science and fact and not
old
wives tales to support only doing a run up and prop check on the first
flight of the day ? I'm talking about a situation where you're flying
multiple flights a day and the engine never completely cools off.



Why do they suspect that the engine/prop is more likely to fail overnight?
Why not check it on the last flight of the day? Frankly, its a stupid idea.
If they think that its too hard on their engine then they need a tougher
engine (On the Helio the mag and prop checks are done at about 15" of MP,
(not much stress)).Similiarly, if they can detect a failed mag on the
takeoff roll then why check it at all while stationary?

There are good reasons to omit a prop of mag check, gravel or ice come to
mind. The reasons are obvious.

There is also a lot of safety to be gained by doing tasks the same way in
the same order every time.

Mike
MU-2

Ok, brother flyers, cards on the table here. I always do a run-up
before taking the active (my Mooney only sees pavement, so gravel
damage isn't a serious consideration) as do I think most of you. I'm a
M20J jock. I have, in some 3000 hours, returned to base after taxing
out only about 4 times. Once, in a normally inducted Mooney Ranger the
carb heat wire broke during that test (quite a surprise when you pull
out a foot of wire!), a couple of time because a radio wasn't working,
once because a bank of spark plugs weren't firing. Never had to come
back because the prop didn't cycle correctly.

I am NOT saying don't cycle the prop! I am wondering what failure modes
you guys have experienced during run up.

I've had in flight mag bank failures, vacuum pump failures, alternator,
radio, and common sense failures too. All but the last lead to a
landing at the nearest suitable airport (ever notice how often a
failure is in solid IFR?). The common sense failure modes did not
result in landing at the nearest airport or turning around, but they
should have.

OK, I've shown you mine. Let's see yours.

Bob Chilcoat wrote:
I'd only run up and check the prop when the engine's not running. You can
get hurt otherwise :-)

Booooooo!!!!!

George Patterson
There's plenty of room for all of God's creatures. Right next to the
mashed potatoes.