both...left...both...right...both...Why?

[Lindberg]

I usually do my mag checks and prop cycling on the roll. I go from both - L - R - both because I can do it without looking at the switch. It's never caused me any problems and I don't figure I'll change my procedures based on anything I've read here. It's funny what grown people will draw lines and argue about.

What RPM are you at when you do it on the roll?

 

[Checkout_my_Six]

What RPM are you at when you do it on the roll?

Oh boy.....there go the brakes.

 

[Stewartb]

What RPM are you at when you do it on the roll?

1500-1800 depending on the surface and length. I do the mag checks but don't expect a problem because in 20+ years in this plane it's never had one. My prop is slow to change pitch below 1800 so sometimes I just do the checks/prop cycle at that. No brakes necessary since the reason for doing a rolling check is soft/loose surfaces. Protecting the prop is SOP.

 

[James331]

Stir away, but there is no reason to return to both. And if there were, it would also indicate reason to return to base for maintenance.

Agreed, both, left, right, back to both.

Kinda reminds me of those OCD people that need to lock and unlock their deadbolts 5 times before leaving the house

I usually do my mag checks and prop cycling on the roll. I go from both - L - R - both because I can do it without looking at the switch. It's never caused me any problems and I don't figure I'll change my procedures based on anything I've read here. It's funny what grown people will draw lines and argue about.

Same here, 80% of the time it's a rolling run up on land and I don't drag the brakes, just energy and distance management, of course on water it's always a rolling run up.

I do run ups at 1700 per the engine manual.

 

[txflyer]

I don't always remember to do it, but I try to do a mag check before shut down.

As an old pilot once taught me, "you don't want to put a sick horse to bed."

It starts the repair process BEFORE your next flight if there's a problem.

 

[flyingron]

Then there's always the "click-click-click-click-BANG!" student pilot mag check when he turns it to off in the process.

 

[orange]

And how much time was saved?

Think about it. If you save 8 seconds on each run-up, and you flew every other day for a year, you would save you a whole 25 minutes.

In reality, most people fly probably once a week or two on average, so over the course of the year, you'd save about 6-8 minutes. Yeah, it's worth debating and arguing and name calling over it. Seriously!

Most of you wasted more time debating this nonsense than you would save over the course of the year if you used it in practice.

 

[Stewartb]

I don't always remember to do it, but I try to do a mag check before shut down.

As an old pilot once taught me, "you don't want to put a sick horse to bed."

It starts the repair process BEFORE your next flight if there's a problem.

You'd be better served by occasionally turning the ignition switch to off to assure the engine will quit. That P Lead check is warranted. Not recognizing a mag problem during the flight or taxiing in is hard to imagine and I wouldn't expect one to break while parked. But that's just my take on it.

 

[kgruber]

of course on water it's always a rolling run up.

I didn't even bother with a mag check off Kidprice Lake. Bill Hicks (WWll-B17, Korea-Skyraider, Viet Nam-AC-47 "Spooky" pilot) asked why?

I told him we were 200 miles from nowhere and that if it got off the water was all I cared!

 

[BigBadLou]

Then there's always the "click-click-click-click-BANG!" student pilot mag check when he turns it to off in the process.

Doesn't Rod Machado say that's how the student pilots signal to each other between airports that they are getting ready to go up in the air and warn others to stay away from them if they want to live?

 

[Bob Noel]

I didn't even bother with a mag check off Kidprice Lake. Bill Hicks (WWll-B17, Korea-Skyraider, Viet Nam-AC-47 "Spooky" pilot) asked why?

I told him we were 200 miles from nowhere and that if it got off the water was all I cared!

but why would you want to leave that place?

 

[neilki]

not one mention of checking for a rise in EGT..?

 

[James331]

not one mention of checking for a rise in EGT..?

It was mentioned.

Last thing I'm trying to do on a runup is save time.

It's like people that just run through the checks like a race, might as well really save time and just skip the whole process. Strangly these folks are the same ones who will do a runup even after a 15min shutdown to pee.

When I select a mag I let it just run for a few seconds to listen to it, see the rpm drop, look at the CHT/EGT, FEEL the plane, the I go to the next mag, then both.

 

[timwinters]

I do the mag checks but don't expect a problem because in 20+ years in this plane it's never had one.

In 11 years I've never found ANY issues while preflighting and/or running up my 182 except for an occasional loose screw here and there.

I guess I'll just start skipping all the rest of it. That'd save me at least 30 minutes per trip.

Kick the tires and light the fire baby!

I don't always remember to do it, but I try to do a mag check before shut down.

As an old pilot once taught me, "you don't want to put a sick horse to bed."

It starts the repair process BEFORE your next flight if there's a problem.

You'd be better served by occasionally turning the ignition switch to off to assure the engine will quit. That P Lead check is warranted. Not recognizing a mag problem during the flight or taxiing in is hard to imagine and I wouldn't expect one to break while parked. But that's just my take on it.

How does killing the engine by turning the mags off tell a person anything more than a mag check does? If you do a mag check and have a significant RPM drop on each mag, then both P leads are good. Conversely, killing the engine with the mags doesn't tell you anything about the health of the individual mags so I'd argue that NO you're not better served by doing it...you're actually better served (and get far more information) by doing a standard mag check.

 

[Stewartb]

Fly floats on and off of flowing water and you'll get used to some of that, too. The one "must do" is to check the oil. That's what I was taught.

And on the mag check? Do what you want. I'm not emotionally invested enough to argue about any of it.

 

[Pilawt]

In 11 years I've never found ANY issues while preflighting and/or running up my 182 except for an occasional loose screw here and there.

Oh, I've turned up the odd bad mag or two -- and one time when lack of a mag drop disclosed a broken P-lead.

Then there's always something like this to make your day more interesting:

 

[Bob T]

Quicker, faster, and saves time.

Aren't those all the same?

 

[James331]

How does killing the engine by turning the mags off tell a person anything more than a mag check does? If you do a mag check and have a significant RPM drop on each mag, then both P leads are good. Conversely, killing the engine with the mags doesn't tell you anything about the health of the individual mags so I'd argue that NO you're not better served by doing it...you're actually better served (and get far more information) by doing a standard mag check.

Engine cut, tells you both pleads are grounding before you shut down, yeah getting a drop on both mags on a normal run up says the same thing, I don't bother with that one ether

 

[Checkout_my_Six]

how would you know if you have two functioning mags?

 

[Henning]

I asked this same question 20 years ago on Avsig, and JD and RS didn't have an answer then.

Randy thought it was a hold over from 70 years ago and had something to do with a radial engine. John just scratched his head.

But, to this day, there is no logical reason to mag check in this manner. In fact, just: both...left...right...both is not only faster but gives better information, in that left and right are consecutive and the drop between them is more easily recognised. Also, less chance of leaving it on one mag.

Both...left...right...both!

Quicker, faster, and saves time.

It comes from the fact that real planes don't have keys. Seriously, think about it when you have toggle switches. Both, Left down, left up, Both, right down, right up, Both. in my 310 I would hit both left mags off and both right mags off at the same time to see the difference in split as well, but I go thru both between them.

 

[Henning]

Also thinking back to the Radial connection, the only rotary mag switch I had was on the Ag Cat with a 1340, and it was Off, Left, Both, Right. You would start the engine spinning in the 'Off' position and start wobbling the wobble pump to prime about 6 blades then hit the Mag to L, when it caught you went to Both. When you did a Mag Check, you went through Both between L & R.

 

[kgruber]

Aren't those all the same?

At least SOMEBODY is awake!

 

[denverpilot]

How many people debating this on this thread have actually found a bad mag?

I've found three. None were subtle when the switch was placed on the bad mag.

The most obvious wasn't a bad mag at all. One of the plug wires had cracked and fallen completely off the plug.

The other two, the mag drop was enough you'd notice it no matter what technique you used.

 

[MBDiagMan]

How much time is actually saved?

Are we really in that much of a hurry doing the runup?

Not me! I will GLADLY give up an extra five seconds to know that I've done everything possible for a thorough and complete runup, BUT, that's just me.

 

[Henning]

If you have a typical Bendix key switch that is L-R-Both-(Start) the issue of not going back to both between them is an issue of wear and tear on the switch. They're known junk to begin with, there's is no reason to unnecessarily wear them out. There is no reason not to just go R-L then back to both. There is absolutely no extra information to be gained by going back to both in between L & R.

Doing something stupid because it is written there doesn't make you cautious, it makes you stupid.

 

[AcroGimp]

If you have a typical Bendix key switch that is L-R-Both-(Start) the issue of not going back to both between them is an issue of wear and tear on the switch. They're known junk to begin with, there's is no reason to unnecessarily wear them out. There is no reason not to just go R-L then back to both. There is absolutely no extra information to be gained by going back to both in between L & R.

Doing something stupid because it is written there doesn't make you cautious, it makes you stupid.

Deciding you know better than the designer and manufacturer of the actual airplane and engine is stupid and acting on that stupidity makes you a test pilot, and not a very bright one at that.

'Gimp

 

[Henning]

Deciding you know better than the designer and manufacturer of the actual airplane and engine is stupid and acting on that stupidity makes you a test pilot, and not a very bright one at that.

'Gimp

Remember that the list may well have been written when the model had toggle switches.

You tell me a technical advantage to going back to both before going back through right to get to left, then back through right to both, please, I want to hear it.

The only advantage is at the parts counter replacing a multi hundred dollar crap switch twice as frequently.

 

[TazzyTazzy]

I used to see students rushing the runup. Both-right-left-both, and sometimes only back to right. Too much hurry. And sometimes they'd accidentally go to Off and then reflexively back on again and make that big bang that fractures expensive mufflers and sometimes even blows the intake elbow gasket out of the cylinder that happens to have open exhaust and intake valves (valve overlap at TDC) at the instant of the bang. They'd yank the carb heat on for one or two seconds and push it off.

What's the proper procedure on bad mag / accidental off? Pull back power and let it die? What about mixture? Then restart on the good mag / both mags if accidental off?

I've not had a bad mag, but good to know how to not break things when this happens to me.

 

[FlySince9]

I haven't read all of the posts yet, but the trend I see here is not what I'm thinking so here goes... The sequence is so you don't leave the switch on only 1 or the other mag. You switch 2 clicks left, 2 clicks right (both) 1 click left, 1 click right leaving you on the selection of BOTH... Any other way may cause you to end up on a single mag rather than BOTH... And I've read a recent post on here where someone did just that, and several guys chimed in with "ME TOO!'

 

[kgruber]

Deciding you know better than the designer and manufacturer of the actual airplane and engine is stupid and acting on that stupidity makes you a test pilot, and not a very bright one at that.

'Gimp

Do you lean your engine for taxi? (must be stupid and not too bright!)
Is that technique in your POH?

Remember Swiss Air 111.....followed the check list RELIGIOUSLY....and they all died. It is an scenario regularly flown in the SIM at FlightSafety. It is thought that if they had tossed their checklist and made an emergency descent (they were on fire!) that they would have had a chance to live.

Flying depends on brains as well as your method, rote.

 

[AcroGimp]

Do you lean your engine for taxi? (must be stupid and not too bright!)
Is that technique in your POH?

Remember Swiss Air 111.....followed the check list RELIGIOUSLY....and they all died. It is an scenario regularly flown in the SIM at FlightSafety. It is thought that if they had tossed their checklist and made an emergency descent (they were on fire!) that they would have had a chance to live.

Flying depends on brains as well as your method, rote.

For aircraft with a mix control ad for which it is called out yes I do to avoid fouling which I have experienced when I missed it in a checklist flow (only human).

In the Yak I don't because there is no mix control (pressure compensating carb) - put simply, I follow the designer/manufacturer's recommendations in every aircraft I fly, which is over 40 different make/models over the last nearly 30 years.

As a recovering Technical Writer I know first-hand the thought, research and internal/external review and approval effort that goes into the development and certification of AFM/POH data (FCOM for heavy iron), and as a current Reliability/Maintainability/Safety professional, in aerospace, I know what happens when pilots don't follow the recommended procedure.

The Emergency, Abnormal and Normal operating procedures (for a certified aircraft) are FAA Approved data (for most planes, older planes have slightly different cert basis), they are part of the Type Certificate Data Sheet and are there for a reason. Airlines have mechanisms in place that allow them to develop, certify and train to their own standards but that is a significant engineering and operations activity, not some pilot sitting around the airport deciding he knows better than Beech or Piper or Cessna, etc.

AS PIC I always retain the right to deviate as needed, and I will (and have) when necessary but I would never presume to think I knew better than the hundreds of engineers and other professionals who are responsible for the design and certification of the aircraft I fly.

SwissAir 111 is a bad choice, they were less than 30 minutes from the coast and did not have a FIRE indication, only odor then smoke. Regardless, it was 20 minutes from first indication (still over the Atlantic Ocean) to loss of the aircraft (offshore). They followed the checklist, caged the cabin electrics and diverted to Halifax ASAP but it was still not close enough given the nature, seriousness and location of the fire. That plane was lost the moment the odor was detected. They were never going to get the ten additional minutes they needed.

Now you or Henning or anyone else for that matter don't have to do it how I do, but don't expect me to fly with you if I know or observe that you don't follow procedure.

'Gimp

 

[kgruber]

AS PIC I always retain the right to deviate as needed,

Okay, I get it. You are smart and bright!

SwissAir 111 is a bad choice,

You need to go and revamp FlightSafety, since they disagree with you.

Now you or Henning or anyone else for that matter don't have to do it how I do, (Thank you for your blessing!)but don't expect me to fly with you if I know or observe that you don't follow procedure. (Pot calling the kettle black)

'Gimp

.....

 

[Lindberg]

Deciding you know better than the designer and manufacturer of the actual airplane and engine is stupid and acting on that stupidity makes you a test pilot, and not a very bright one at that.

You're talking to Henning. He probably wrote the POH.

 

[jesse]

How many people debating this on this thread have actually found a bad mag?

I've found three. None were subtle when the switch was placed on the bad mag.

The most obvious wasn't a bad mag at all. One of the plug wires had cracked and fallen completely off the plug.

The other two, the mag drop was enough you'd notice it no matter what technique you used.

I've found a lot of bad mags. Though, most of them I found in advance, by checking the mags in cruise.

 

[AcroGimp]

Perhaps you can explain what bit of systems knowledge not contained in the FCOM and SwissAir training material would have qualified the flightcrew of SwissAir 111 to decide to deviate from the smoke in cabin checklist and the max landing weight limitation based on the information they had at the time?

The only potential mistake they made was in their initial desire to return to Logan after the Pan Pan call, which they changed 4 minutes later when they declared the Emergency once they realized they had an actual fire. It was already too late at this point mind you, according to the investigation team.

If FSI trains something other than the manufacturer's procedures it would be to a specific operator's procedures which in theory should have gone through engineering and operations review as well as with the operators' FAA inspector and may or may not be specific to the SwissAir 111 accident (I have no personal knowledge).

Perhaps you can explain why the TSB itself said that SwissAir 111 was not recoverable, even landing at Halifax, given the sum total of data they reviewed following the accident (millions of pieces of debris, CVR and FDR data, ATC audio, radar tapes and sim work)?

I was not offering a blessing, only stating I don't like to fly with careless/unprofessional pilots who think they know better than the guys who designed, built and certified the equipment they are operating.

All PIC's have the right and responsibility to deviate if necessary, in the heat of the moment, but that is not the same as cart blanche approval to willy-nilly choose which approved procedures you are going to follow or not - my concern is this attitude typically extends to the reg's as well and that is why I personally don't fly with guys who demonstrate that approach to flying. Your mileage, of course, may vary.

Gimp

 

[Stewartb]

Man, you guys are sure stubborn. When I'm sitting on the strip with my wife and kid and dog and a couple of hundred pounds of stuff looking 1000' downfield at 80-90' trees buffeting in a crossing wind I want to know that my engine systems are healthy. mags are one that we're taught to check. How it gets done isn't important to me. I just want to trust what's going to happen when I push the loud knob to the stop. Y'all should do what you think's best for the reasons that matter to you and worry less about what other fellas do for reasons that make sense to them. It's a discussion, not a committee meeting to write a procedures manual.

 

[WhiskeyPapa]

With a properly maintained system there is no "recovery." If you need to "recover" you need to taxi back and do proper maintenance.

Are you not seeing a drop when you go to one mag?

 

[WhiskeyPapa]

I didn't even bother with a mag check off Kidprice Lake. Bill Hicks (WWll-B17, Korea-Skyraider, Viet Nam-AC-47 "Spooky" pilot) asked why?

I told him we were 200 miles from nowhere and that if it got off the water was all I cared!

Thing is that if there was fouling a good way to handle it in the boonies would have been high RPM run up (2000+) with heavy leaning… a couple minutes of that and the mags could have been running clean again… would have led to a safer take off…

 

[Henning]

Are you not seeing a drop when you go to one mag?

There are some planes I will not see a drop on an analog tach if I do the runnup by the book RPM, especially on planes with a climb prop asking for a 1700 rpm runnup. If you have a good well timed set of mags, sometimes that isn't enough load to produce a drop and I have to go to 2100rpm to get enough load to see a drop.

 

[WhiskeyPapa]

In the Yak I don't because there is no mix control (pressure compensating carb) - put simply, I follow the designer/manufacturer's recommendations in every aircraft I fly, which is over 40 different make/models over the last nearly 30 years.



'Gimp

In your Yak, do you run up to high RPM just before shutting down? We did this religiously in Russia.