Author Topic: Question about pre-take-off engine test  (Read 5734 times)

Offline Frank N. O.

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Question about pre-take-off engine test
« on: November 05, 2007, 03:10:37 AM »
I was wondering, when I got my flight in the Cardinal the pilot did what appeared to be a full throttle engine test before we rolled onto the runway. Is it normal that the tires have grip to hold a plane on full thrust? Also, is it always something one does to check the engine is in working order (I assume the various gauges are checked, like oil-pressure, intake-pressure, fuel-flow and such)?

Frank
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Offline Fabo

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Re: Question about pre-take-off engine test
« Reply #1 on: November 05, 2007, 12:51:30 PM »
Also, is it always something one does to check the engine is in working order (I assume the various gauges are checked, like oil-pressure, intake-pressure, fuel-flow and such)?

Frank

Yep, in slovak we call it "motorová skúška", english term is... Engine runup, yeh that should be it.
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."

Offline Rooster Cruiser

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Re: Question about pre-take-off engine test
« Reply #2 on: November 05, 2007, 03:21:48 PM »
Engine runup in a Cessna checks over several engine parameters and is done at 1700-1800RPM.  The first item on the checklist is the dual magnetos.  The PIC moves the ignition key from "Both" magneto position to "Left", then "Right" and notes the drop in engine RPM.  By doing this you remove one magneto and its associated set of spark plugs, and check on the condition of the one set of plugs.  The engine should show a 75-150RPM drop due to less efficient combustion by running on only the one set of plugs.

If the engine runs rough, it indicates fouled plugs caused by either lead or carbon deposits.  The PIC can run the engine up to 2000RPM and lean the mixture to best power for one to two minutes to attempt to burn the deposits off the fouled plugs.  If this technique does not work, take the airplane back and have a mechanic check it.  If you have a zero RPM drop on one magneto, then the other magneto is not being properly grounded and needs to be checked by a mechanic.  Should you have this happen, by no means do you touch the prop afterwards!  With the ignition key off, you still have a hot mag, and the prop should be treated like a loaded and cocked gun.

After the Mag check, Carburetor Heat is checked for correct operation (in carburetored engines).  There should be a 100RPM or so drop with carb heat applied.  No drop would indicate a faulty heater or a broken control cable.  Again, back to the ramp for Julio to check it out.

Propellor governor operation is checked next if the airplane is equipped with a constant speed prop.  The PIC cycles the prop control from HIGH (fine pitch) to LOW (coarse pitch) several times to ensure the propellor governor is working correctly.

Engine instruments are next on the checklist (CHT, Oil Temp and Pressure).  They should all be within their green operating arcs before you take to the runway and apply full power.  Electrical system is the next check by applying a load on the system (a landing light is typical) and observing the ammeter.  Ammeter needle should show a slight discharge, then return to zero as the regulator adjusts to the higher load.  No drop indicates a burned out landing light or an inoperative ammeter, while a constant discharge indicates a weak or inoperative alternator (and a trip to see Julio again!  Hehe).

Suction guage is checked next.  The suction guage shows the pressure drop in the vacuum system (which is powered by an engine driven pump) and supplies vacuum pressure to the artificial horizon and directional gyro.  It should be within its green operating arc as well.

Lastly, some checklists require the PIC to bring the throttle all the way to idle to ensure the engine will still operate.  Otherwise, if everything has checked out during engine runup, you should be just about ready for flight.

On a multi engine airplane you do all this twice.

Hope you enjoyed the ground school lesson, Frank.  That will be twenty five euro.   >:D >:D >:D

RC
« Last Edit: November 05, 2007, 11:16:27 PM by Rooster Cruiser »
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Offline Frank N. O.

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Re: Question about pre-take-off engine test
« Reply #3 on: November 05, 2007, 04:02:30 PM »
This is what I love about this forum, tons of learning! New languages and important safety procedures and the principles behind them! I just want to keep learning! And I'm still on my a-walk-each-morning routine that Mike inspired me to start friday morning (the very morning I started) and I have seen clear improvements!

Frank
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."
— Leonardo da Vinci

Offline Rooster Cruiser

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Re: Question about pre-take-off engine test
« Reply #4 on: November 05, 2007, 11:11:14 PM »
Quote
And I'm still on my a-walk-each-morning routine that Mike inspired me to start friday morning (the very morning I started) and I have seen clear improvements!
Good for you, Frank!  ^5555555555 dude!
"Me and Earl was haulin' chickens / On a flatbed outta Wiggins..."

Wolf Creek Pass, by CW McCall

Offline Baradium

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Re: Question about pre-take-off engine test
« Reply #5 on: November 07, 2007, 03:32:58 AM »
On multi-engined aircraft don't forget the feather check.  ;)
"Well I know what's right, I got just one life
In a world that keeps on pushin' me around
But I stand my ground, and I won't back down"
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Offline Rooster Cruiser

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Re: Question about pre-take-off engine test
« Reply #6 on: November 07, 2007, 04:56:37 AM »
I was trying to keep my post short as I had to check out of my Hotel room in Leon, Gto, Mexico.  Hehe   ;D
« Last Edit: November 07, 2007, 05:00:16 AM by Rooster Cruiser »
"Me and Earl was haulin' chickens / On a flatbed outta Wiggins..."

Wolf Creek Pass, by CW McCall

Offline G-man

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Re: Question about pre-take-off engine test
« Reply #7 on: November 07, 2007, 05:50:50 AM »
On multi-engined aircraft don't forget the feather check.  ;)

I do the whole "chicken" test...

Make the sign of a cross on you body and repeat after me:

Spectacles

Testacles

Pocket book and

Watch.. ::whistle:: ::whistle::
Life may not be the party we hoped for---but while we're here--we might as well dance..........

Offline Frank N. O.

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Re: Question about pre-take-off engine test
« Reply #8 on: November 07, 2007, 05:54:02 AM »
Oh man you guys/gals are the best anti-depressant ever invented, and you actually give away nuggest of wisdom too ::rofl:: ::wave::

Frank
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."
— Leonardo da Vinci