"Controls free and correct" in the run-up area - why wait until then?

RussR

RussR

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Most (perhaps all) checklists that I've seen have the "controls free and correct" check done as part of the "Engine Run-Up" section. This is the way I was taught as well, and the checklists cement it as a standard procedure when teaching.

But why there? Why not do it as part of your preflight, or pre-taxi check? If I'm going to find out the controls are jammed or I forgot a gust lock, I'd rather find out in the parking spot before I start the engine, so I don't have to waste time taxiing (or I can fix it then).

A client of mine does do a pre-taxi check like this, which I think is a great idea. He also does it in the run-up area as well.

But why is it seemingly "standard" to wait to do this until you're down in the run-up area? Or is it not standard? I looked in several Cessna and Piper POHs, as well as some random Checkmate checklists for various airplanes, and it was always in the "run-up" section.
 
RussR said:
A client of mine does do a pre-taxi check like this, which I think is a great idea. He also does it in the run-up area as well.
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At engine start and at run-up. As previous message stated also, you should have been hitting all that in the walk around as well (3 checks)
 
I do it on the way to the run up area and then again at the run up area as per the checklist.
 
The OP writes an excellent question. Light airplane flight controls with cables and pulleys should be exercised - and listened to - before the engine is started. One might never hear the sound of a cable sawing a flange, or something binding under strain - with the engine running.
 
Just a last minute check in case something changed. Perhaps ice formed since parking. Maybe your pax shifted position and now is blocking the controls...found that one on more than one occasion.
 
You can modify the checklist as you wish as long as you don't omit any items... If you want to put that particular item in the "before start" section... go ahead... Your walk around may not reveal mis-rigged controls unless you can see the Yoke/Stick while you are moving the surfaces...(obviously :rolleyes:)
 
Things might have changed. I had a case last year of controls free in the hangar, but binding discovered during run-up.

Ron Wanttaja
 
I think the (obvious?) reason is to check them immediately before takeoff.

Admittedly a remote possibility, but doing it earlier in the process would not catch any failures/problems enroute to the runway*.


*Was it a C130 that crashed after a clipboard or equivalent had fallen and blocked the controls?

Edited to add: composing my post as Ron was posting his.
 
FastEddieB said:
I think the (obvious?) reason is to check them immediately before takeoff.

Admittedly a remote possibility, but doing it earlier in the process would not catch any failures/problems enroute to the runway*.


*Was it a C130 that crashed after a clipboard or equivalent had fallen and blocked the controls?

Edited to add: composing my post as Ron was posting his.
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Yeah, AF C-130 had an NVG case wedged behind the yoke. Flight control check wasn’t part of the checklist for that operation. I imagine it is now though.
 
Velocity173 said:
Just a last minute check in case something changed. Perhaps ice formed since parking. Maybe your pax shifted position and now is blocking the controls...found that one on more than one occasion.
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This! I wish I had a dollar for every time I hit a knee or two with the yoke, and that's after saying "watch your knees" before deflection...
 
There are good reasons to do it before start-up but always a good reason to do last thing before takeoff.

Think distractions and unplanned events. You do a preflight but there’s a phone call afterwards. A small cell develops overhead or a dust devil comes through and someone decides to reinstall the control lock. Operations resume and you quickly run through an an abbreviated preflight. Taxi out, perform full run up checklist but there’s no free and clear check included. Rolling down the runway... “hey, I know I checked the controls, what’s wrong?”.

Very unlikely for sure but the very unlikely sequence of events and unexpected distractions is what you are trying protect yourself from.

I spent many years flying RC. No cockpit checks, sumps or dipsticks. But with the engine running we used to do a power check (full power and hold it at an extreme AOA to check fuel flow), and then a control check before letting it go. Still makes sense. No matter how many checks were done in the pit.


Sent from my iPad using Tapatalk Pro
 
There’s nothing that prohibits you from checking the controls any time you want...preflight, before start, after start, taxi, whatever. But as others have said, the manufacturer puts it in the checklist where they do because it should be checked as a final item before takeoff.

Keep in mind that a checklist isn’t a complete document for how to fly the airplane, nor is it intended to be. Significant airmanship needs to be used in conjunction with the checklist to create a safe flight.
 
Ken Ibold said:
External preflight should include manipulating the elevator and ailerons by hand and observing yoke movement if possible. That will detect a gust lock.

The run-up free and correct is a final check.
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That is how I teach it. Move the controls while preflighting. During taxi I teach correct placement of the controls for wind, so there’s another check.

I agree with Ken, during run up check is the final check, or “last chance”.
 
RussR said:
A client of mine does do a pre-taxi check like this, which I think is a great idea. He also does it in the run-up area as well.
Click to expand...
I also do it like this. Control check before starting the engine, and another in the run up area.

I'd rather find there is a problem before I vacate the area where I might be able to resolve it myself.
 
I check the controls as I get into the plane for the first time. Only takes a second.

I place my left hand on the yoke, thumb pointed upwards. Then I turn the yoke to the right. My left thumb is now pointing at the right aileron, and it should be in the up position, left side should be down. Then I pull the yoke all the way back, and turn to the left. My left thumb is now pointing to the left side which should be in the up position. Then I return to normal.

Then I'll check again after engine(s) start and before I start moving. Then one last time as I take the runway.

The story as to why I do that.

Once I was doing the follow the checklist thing. I checked controls free and correct. Did the mag checks, and pulled onto the runway and went to take off power. A little left cross wind, so I added a little aileron to correct. NO MOVEMENT.!!!! I could not turn the yoke. It was stuck in place. I could pull and push, but no turn. Thankfully the brakes worked.

The mechanics found the aileron piano wire had broken inside the hinge. Probably a good panic yank would had freed it up. Or maybe not.
 
Zeldman said:
The mechanics found the aileron piano wire had broken inside the hinge. Probably a good panic yank would had freed it up. Or maybe not.
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I notice on one of the rentals I fly (a trainer) that it has some play in the ailerons when I move the by hand. Not a bunch, but it seems to come from the wire being worn or the hinges themselves.
Makes me a little nervous.
Is there a 'minimum' or any metric on wear/time to replace these?
 
my checklist have it before engine starting then again at run up.
 
Skyrys62 said:
I notice on one of the rentals I fly (a trainer) that it has some play in the ailerons when I move the by hand. Not a bunch, but it seems to come from the wire being worn or the hinges themselves.
Makes me a little nervous.
Is there a 'minimum' or any metric on wear/time to replace these?
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that might not be the wire, i had a similar thing going when i bought her.. it ended up being a push rod (OR whatever its called) on the aileron hinge
 
Zeldman said:
The mechanics found the aileron piano wire had broken inside the hinge. Probably a good panic yank would had freed it up. Or maybe not.
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Yay! I teach students to check the hinges to include the mounting bolts and nuts AND that piano wire! Now I have a new story to scare ‘em with! ;)
 
mscard88 said:
Yay! I teach students to check the hinges to include the mounting bolts and nuts AND that piano wire! Now I have a new story to scare ‘em with! ;)
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Be sure to add the part about the plane being full of orphans and that there was a truck parked on the runway that was full of nuclear waste and spiders.....:lol::lol::lol:
 
Zeldman said:
Be sure to add the part about the plane being full of orphans and that there was a truck parked on the runway that was full of nuclear waste and spiders.....:lol::lol::lol:
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I will except it’ll be a plane load of hookers and Commie tanks on the runway.
 
WannFly said:
that might not be the wire, i had a similar thing going when i bought her.. it ended up being a push rod (OR whatever its called) on the aileron hinge
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I do check the nuts/bolts/rods, etc., but this movement can be seen in the actual hinge like the wire is worn down. I know this bird has a ton of hours on it... It's a '77 Cessna 172 and has been the main trainer for I'm guessing 3 decades. I'm going to report it just to see if it gets fixed. It's a fairly important part I reckon mmhmm
Wondering if it's ever been replaced..
 
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I don't see that part of the checklist as particularly limiting; nothing says you can't check them at other times in addition to when the checklist directs.

In the USAF aircraft I flew -- most with hydraulic flight controls -- we performed a flight control check in the chocks with a ground crew member observing and relaying the deflection direction of the individual surfaces with the stick in specific positions (especially an issue in the Eagle with two rudders and independently-moving horizontal stabilizers), and an additional "sweep" of the controls before taking the runway. With those aircraft it wasn't possible to check movement of the control surfaces on the walk-around.
 
I do that while taxiing. But also during runup- because it’s on the checklist. Run up checklist time is a time to take a deep breath and go through the list with intention. Once we start skipping because we did it at another time, it can start to get wonky!
 
It's the first thing I do after fastening my seatbelt. Actually, I check it during the walk-around and then to make sure nothing, like me, is in the way, after my seatbelt goes on.
 
As you step up into more advanced airplanes...did the autopilot accidentally get turned on? Did ice form in the hinges because you brought a warm airplane out of the hangar into cold, moist air, or maybe splashed water up into a cold-soaked airplane? Did you have the control lock installed for taxi in 30+ knot tailwinds so the controls wouldn't slam around?

Any number of reasons exist to check controls before pulling on to the runway...and as has been indicated, there is no prohibition on doing additional checks earlier.
 
How many remember to check the rudder controls as well? I once had an exceptionally tall passenger that unknowingly slipped his feet under the rudder pedals to get comfortable. Application of right rudder was met with resistance and came with a resounding scream from the right seat. I was glad to discover this then and not blazing down the runway.
 
midwestpa24 said:
How many remember to check the rudder controls as well? I once had an exceptionally tall passenger that unknowingly slipped his feet under the rudder pedals to get comfortable. Application of right rudder was met with resistance and came with a resounding scream from the right seat. I was glad to discover this then and not blazing down the runway.
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only during taxi and then visually before run up and instruct pax… that that's not a foot paddle !!
 
Checking them on the walk around is a good thing, but confirming them at the run up pad includes the effect of that pesky propeller pushing air over the surfaces.

Probably nice to know they are true and correct with that going on, eh?
 
Ken Ibold said:
External preflight should include manipulating the elevator and ailerons by hand and observing yoke movement if possible. That will detect a gust lock.

The run-up free and correct is a final check.
Click to expand...

This is what I was taught from day one. Preflight, again doing instrument check and finally during run up checks.

Thumbs up check!
 
I will say Controls Check doesn't always find the issue. I've blasted out of O'Hare to find out as we climbed out that we could barely turn. The yoke took almost every bit of your strength to move.

Turned out a pulley on the Aileron Feel Unit was seizing up as we increase airspeed.
 
Bill Watson said:
I spent many years flying RC. No cockpit checks, sumps or dipsticks. But with the engine running we used to do a power check (full power and hold it at an extreme AOA to check fuel flow), and then a control check before letting it go. Still makes sense. No matter how many checks were done in the pit.
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I lost an rc plane because of a failure to do a control check. The aileron servo was reversed, and when I pushed the control stick for a left bank, it banked right. Of course, the instinct is to give it more left (which in fact, is more right). Instant crash...you simply can't get your brain around it quickly enough when low to the ground.

External control locks scare me. I like the one I have, that links the control stick to the rudder pedals. Impossible to miss!
 
Slightly off topic because this guy's flght controls were free and correct until he took off:

I watched a guy almost die because of jammed controls on an ultralight. He was ferrying it to a new owner, about a 4 hr flight away. He topped off on fuel, then filled up at least one 5 gallon jerry can as a reserve. He strapped the can (might have been more than one) into the passenger seat. This aircraft had two seats, side by side, with a center stick. I was either fueling or preflighting when he departed. As he rotated the tank slipped down into the footwell and jammed the stick left. He got about 30agl and made a sharp left turn. I started to move in his direction because I knew he was going to crash. But he forced it to stay in the air long enough to complete the 360 and land. He taxied back to the ramp and shut down right next to me. First thing he did was light a cigarette. It took him three or four tries because he was shaking so bad. After about 30 minutes and a lot of extra straps for the gas cans, he took off again.
 
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