Instructor not concerned about engine failure, restarted, and continued lesson.

[UnAnswerd]

Hehe. It wasn't in flight. It was a little mishap on the taxiway...

Thinking back to my first few lessons, I remember a time when I was having quite a bit of trouble taxiing the airplane. My instructor would always say, "slow down with the throttle, not the brakes"! I remember he said this and in a bit of frustration I pulled it all the way back. The engine quit right then and there. My instructor seemed surprised and simply claimed "never seen that before". Regardless of this little mishap, we got it started again and took right off, apparently giving it little attention. I was just wondering what some of you guys might think about the safety of doing this. I guess it stands to reason that if during the runup everything stays good, then you're fine. Either way, just wanted to get an opinion.

 

[GravityHater]

if it was idling less than about 550 then it just needs to have the idle stop reset. or maybe you have to lean it on the ground more.

 

[viper548]

If the engine was cold, i'd buy into it. Did you abruptly reduce the throttle to idle or was it smooth? If the engine was warm and you reduce the throttle smoothly, it should still run at idle. If not, it needs to be looked at.

 

[UnAnswerd]

if it was idling less than about 550 then it just needs to have the idle stop reset. or maybe you have to lean it on the ground more.

I figured that's probably all it was. Carbureted engines probably have a tendency to load-up when we taxi with the mixture full-rich.

 

[Flying Illini]

You pulled the throttle back to idle and the engine quit? And it didn't do this the other times you pulled the throttle back? How quickly did you retard the throttle?
With the little info provided, I would probably have restarted and do the exact same thing to see if it quit again. It it did, the flight would be over...if it didn't, the flight would be over too...until a mech was able to look at it.

 

[Geronimo4497]

Very common. If the idle mixture is not set correctly (the correct setting changes from season to season with OAT variations), the engine may quit with the throttle all the way back. Normal idle should be about 550-700 RPM on the ground, once the engine is up to "normal" temperatures. Have a mechanic tweak the idle setting, and life should be good.
If your flight was the first flight of the day for that airplane, you may tend to see this "problem". Just watch your RPM when you are going to slow down without using the brakes (which I agree with for most small piston planes; the brakes are for runup only). If the power starts to drop below 500, just give her a little nudge of power and you should be able to catch it before quiting.

Obviously, a thourough run up should catch any problems. Fly Safe.

 

[9GClub]

After the mag check in the 150, I always pull on the carb heat, check for RPM drop, and then cut power all the way for a few seconds to make sure she's still crankin'...... isn't this standard practice for the run-up?

 

[UnAnswerd]

After the mag check in the 150, I always pull on the carb heat, check for RPM drop, and then cut power all the way for a few seconds to make sure she's still crankin'...... isn't this standard practice for the run-up?

I don't know. I've never taken the engine much below 1000rpm after the runup.

 

[hotwings402]

I had this happen and we took of anyways had a engine failure in the stall headed engine ran funny the whole time headed back to the airport and then another engine failure on final landed the ac deadstick then limped back into the ramp......Messed up carb maybe even the settings but a messed up carb can give you this.

 

[hotwings402]

BTW as above pull the throttle to idle on the runup with carb heat, it should never quit it is never normal, it is worse case scenerio as on the landing the engine will be warm and idle slightly higher anyways, idle can differ between ac on the C-170 its like 350 rpm very low.......

 

[Geronimo4497]

After the mag check in the 150, I always pull on the carb heat, check for RPM drop, and then cut power all the way for a few seconds to make sure she's still crankin'...... isn't this standard practice for the run-up?

That SHOULD be the standard practice. If not, start doing it. Remember not to freak out if the engine is cold, however. If it looks like it might quit, let it idle at 1000 for a while longer, and try it again. Once the oil temp is moving off of the peg, the engine should not quit.

 

[UnAnswerd]

Good info here. Thanks.

 

[User546]

The last item on my runup list on all single-engine airplanes I fly is the "Idle Check".

I'll slowly bring the throttle back to its stop, and let it sit idle for a couple seconds. You can tell right away if the engine is going to die or not. If the engine will not idle without trying to shut off, thats an immediate No Go decision for me. To me, it's better to be safe then sorry.

I fly an older Mooney that for a long time kept trying to die everytime I'd run the idle check. Ended up being the mixture control idle was set inproperly from recent maintenance (among other things), and after a few trips back to the mx hanger, we finally got it tweaked just right.

A guy that also flies the Mooney use to fly it anyways, with the theory that he never brings the throttle all the way back to idle until he's crossing the threshold on landing. To each their own I guess, but an engine that will try to die on me everytime I bring the throttle back to idle is no good to me. It could always be an indication of a far bigger problem, which might not manifest itself until a far more inconvenient time!
.
.
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[ackattacker]

On the 402's, the inboard engine would always try to quit anytime you took a turn too fast on the taxi. Embarrassing as hell when you got 9 passengers. Uhhhh... no big deal folks... completely normal...let me just crank it back up.... @#!%@ thing... now its flooded... uhhh, no problem, let me just open the throttle, mixture back, crank it more, hehe not quick enough with the mixture, one more time folks, sure it'll fly....

 

[SiuDude]

BTW as above pull the throttle to idle on the runup with carb heat, it should never quit it is never normal, it is worse case scenerio as on the landing the engine will be warm and idle slightly higher anyways, idle can differ between ac on the C-170 its like 350 rpm very low.......

Dude, can you put together a coherent sentence?

 

[Kream926]

im almost certain that the idle carb heat check is a POH checklist item. but then again i was doing a check out in a 172P and when i did that the guy looked at me and asked what the hell i was doing. so i guess it is not practiced everywhere

 

[jaxpilot]

happened to me before in an SP, this plane did it to a couple of different pilots. Well it was supposed to be fixed and all was well, then in flight I showed a power off stall to a student, pulled the power to idle, and the engine quit. We tried to restart it many times but to no avail. Ended up crashing in a field and destroying the airplane but me and my student were ok (he had a laceration on his leg). This is a problem with many piston engines and one of the many reasons I hate flying piston singles now.

 

[MDAutry]

I took an internship at a state facility which has a small cessna and I couild not believe the incompetence in regard to the maintenance practices. This guy was an ex military crew leader and he didn't know that a carb needed a spring on it in case the cable was pulled out; which, by the way happened to me and my best friend. FYI, my buddy was on his private checkride when the throttle pulled all the way out into the cabin and the engine went full throtle. He was lucky his mechanic was not a moron and knew to put a spring on the carb fly valve.

To answer your question... If the engine was warm which should happen on a small cessna in about 5 mins if it is not freggin cold... The engine should not quit running at idle unless something is way wrong and you should consider flying somewhere else.

 

[A Squared]

On the 402's, the inboard engine would always try to quit anytime you took a turn too fast on the taxi. Embarrassing as hell when you got 9 passengers. Uhhhh... no big deal folks... completely normal...let me just crank it back up.... @#!%@ thing... now its flooded... uhhh, no problem, let me just open the throttle, mixture back, crank it more, hehe not quick enough with the mixture, one more time folks, sure it'll fly....

So which one is the inboard engine on the 402?

 

[Frmr Avro Drvr]

So which one is the inboard engine on the 402?

I thought the same thing but then the words "took a turn" hit me.

"Inside engine" would have been better but it all made sense eventually.

 

[erj-145mech]

I took an internship at a state facility which has a small cessna and I couild not believe the incompetence in regard to the maintenance practices. This guy was an ex military crew leader and he didn't know that a carb needed a spring on it in case the cable was pulled out; which, by the way happened to me and my best friend. FYI, my buddy was on his private checkride when the throttle pulled all the way out into the cabin and the engine went full throtle. He was lucky his mechanic was not a moron and knew to put a spring on the carb fly valve.

.

What are you talking about? I've been working on GA airplanes since 1975, and have yet seen a spring on the throttle. I'm calling Ca CA on this one. Automobiles have springs to take the throttle to idle, but there hasn't been a certificated airplane yet have a spring to take the throttle to full. Think about it, how are you going to get the power back to land?

 

[hotwings402]

I have never seen a carb heat, mixture or throttle with a spring on it, and if you do that and its not a originally part of the airplane don't you need a 337? It would be a good idea to have it on the mixture or throttle. The mixture cable on my a/c is clamped to the carb control by a allen wrench screw, not very safe if you ask me, lets just say I check that for tightness every oil change. lol

 

[minitour]

im almost certain that the idle carb heat check is a POH checklist item. but then again i was doing a check out in a 172P and when i did that the guy looked at me and asked what the hell i was doing. so i guess it is not practiced everywhere

The first time I saw that was during my CFII training. My instructor did it every time. Well, it never stuck and a week and a half ago (or so) I had an engine fail on me ON THE RUNWAY at night as the student was doing stop and goes...Tower wasn't too happy...and I don't think the jet behind me was thrilled either, but we got it started and taxi'd off the runway rather quickly

I guarantee it will be part of every run-up I do now...every single time! If the engine had quit another 45 seconds later...we could've been in a world of hurt.

-mini

 

[BoilerUP]

happened to me before in an SP, this plane did it to a couple of different pilots. Well it was supposed to be fixed and all was well, then in flight I showed a power off stall to a student, pulled the power to idle, and the engine quit. We tried to restart it many times but to no avail. Ended up crashing in a field and destroying the airplane but me and my student were ok (he had a laceration on his leg). This is a problem with many piston engines and one of the many reasons I hate flying piston singles now.

An SP is fuel injected and should not have been a major PITA to get restarted with a windmilling prop unless it was flooded.

A school I used to instruct at had a 98 R model and it would try to quit during the idle check. Once quit on a buddy of mine when we were going to do some approaches. We said "hmmm", restarted the thing, the runup checked good, and we went flying with no problem. It was written up that the idle was set too low, and was fixed during the next 100 hour inspection.

Now I know another guy that went flying in a Bonanza and didn't know you kept the electric fuel pump OFF for landing...he learned real fast when the IO-550 quit on short final! Fortunately he was a bit high and fast and made the runway no problem. Guess it pays to be familiar with your airplane...

 

[erj-145mech]

The mixture cable on my a/c is clamped to the carb control by a allen wrench screw, not very safe if you ask me, lets just say I check that for tightness every oil change. lol

Has it ever come loose? Didn't think so. The magnetos are only held on with a couple of 5/16 nuts holding a clamp onto the base, they don't come loose either. Go to the NTSB or FAA databases and find how many have come loose. Think about this, you're fat dumb and happy cruising at 9500 feet, majically your cable comes loose and the spring takes the mixture to full rich. Bingo, now you have a real problem. You have to find a landing spot because your engine got too rich to run.

I don't think that you'll find a mechanic willing to do the installation, or an FAA inspector willing to buy it off.

I'm a disciple of the KISS principle, Keep It Simple Stupid! If is ain't broke, don't fix it.

 

[VNugget]

Think about it, how are you going to get the power back to land?

I thought about it long and hard, and couldn't think of a single way to cut the power on a piston engine. HELP, is this a trick question??

 

[RogerPodacter]

Full Cut-off valve....

 

[MDAutry]

I will simply say that if you are unfamiliar with the carburetor spring and its location then I would not tell others it does not exist. I will find you a good MX parts index and let you see when I have time. Also, the mixture does not have this spring it is only the carb buterfly valve that has the spring. The springs whole purpose in life is to give you full power when the throttle cable becomes disconnected or broken due to vibration etc. This is very logical by the way, a manufacturer would rather you have full throttle than no throttle... esp. in a single.

 

[A Squared]

but there hasn't been a certificated airplane yet have a spring to take the throttle to full.

Really? the Stromberg Carburetor on the DC-6's R-2800 goes to about 3/4 throttle (aproximately METO power) when the cable breaks. I've had it happen to me personally. I'm fairly certain the DC-6 is certificated.

Think about it, how are you going to get the power back to land?

When the time came, we were able to shut the engine down without much difficulty.

Has it ever come loose? Didn't think so.

OK let me get this straight, you're a mechanic and you don't think that throttle controls ever fail? I've got news for you In addition to it happening to me, I have two friends who it happened to. One in a Citabria and one in a 185. Here's an accident where a throttle control failed. There are also a few accidents around which resulted from throttle control failure. In fact there's an AD out for the IO-520 which addresses the way the cable is secured to the throttle arm.

 

[erj-145mech]

First off, I didn't say that throttle control failures were not going to happen. I said that a properly installed mixture control on a general aviation airplane wasn't likely to come loose.

You're going to have to show me in an IPC or a Stromberg PT series carburetor maintenance manual about this METO auto opening proceedure. I've installed and rigged many carbs on all sorts of R-2800's from Corsairs, to Harpoons to Thunderbolts with all different series 2800's from -17's to CB-16's, and I sure don't remember any springs installed to open the throttles. There's a dashpot interconnect linkage to an enrichment valve, but thats not the same. Thats gotta be a real bitch to rig those carbs. Idle position times four, full open position times four, and cable control cable break/METO postion times four, and keeping the knobs together too.

I'd like to know how you control an engine that has a cable break, with a spring that takes the engine to max power? The only control that you have is the mixture and the mags. If you turn off the mags and turn them back on again, you're going to get one hell of an afterfire, and possible blow the exhaust system apart, if you lean the engine with manual lean to control the power, then your CHT's and EGT's are going to go ape.

Aircraft components do fail, and a chronic situation will result in an airworthiness directive being issued. The typical throttle cable in a vintage aircraft will also fail if it has not been maintained properly. Those 1/16 dia steel cables will fray and they will corrode, then they will fail. If you have an aircraft that has frayed and corroded cables, then they are not being maintained properly.

The AD that you're referring to was issued in January 1987 and it was to install a castellated nut with cotter pin on the throttle cable rod end bearing. Cessna requested this AD ( via a service letter) because they screwed up and didn't have a proper safety device installed at the factory. There were no failures, only potential failures. When you come to think of it, anything in an airplane is a potential failure.