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fireflybob
14th Jan 2008, 18:49
You are flying around on a nice VFR day and the engine suddenly starts to run roughly - what would you do?

Dysonsphere
14th Jan 2008, 18:53
Carb heat full / fuel pump on if you have one / change tanks if an option / start looking for a nice field /find it then see what else is happening with engine. Then use radio.

BackPacker
14th Jan 2008, 18:57
You can also check if the roughness goes away when running on just one magneto. But only after you've picked a field and informed ATC.

MIKECR
14th Jan 2008, 19:02
shut it down, use the other one!!:}

BackPacker
14th Jan 2008, 19:08
There was this single-engine fighter jet a few years ago who had a rough running engine. He declared a pan, got vectors back to the field and was then held up by ATC because there was a B-52 on final, also on a pan, "with one engine shutdown".

"Ah, yes, the dreaded seven-engine approach. I'll hold." was the dry response of the fighter pilot.

RatherBeFlying
14th Jan 2008, 20:26
Carb Heat -- On immediately

Then check Primer Locked.

If engine getting rougher for a bit after carb heat applied, ice is likely. It should smooth out once ice melted.

Mixture depends on high you are and temperature. The last time I flew a C-172 in the winter, there was quite the nasty stumble arriving overhead the airport after a descent at lower revs. Carb heat made it go away:ok:

Fuel pump can help or make things worse -- keep an eye on fuel pressure if playing with it. Even better, know what the normal fuel pressure in various flight regimes should be.

If still no cure, try each mag as mentioned before.

Oil temperature/pressure, EGT, CHT may all have hints.

IO540
14th Jan 2008, 20:29
You are flying around on a nice VFR day and the engine suddenly starts to run roughly - what would you do?

You land at the first airport from which your girlfriend can get a cheap airline back home :)

Seriously, it is system dependent. Pull out carb heat, mixture full rich (unless already at high altitude), pull alternate air (if fuel injected). Full pump ON. The rest depends on available engine instrumentation: EGTs, CHTs, fuel flow rate. There is even a failure mode on some Conti fuel servos which gives you a rich cut and the only way out is to lean drastically.

You have to know the plane and all its systems before you get airborne.

matspart3
14th Jan 2008, 20:45
swear..........then do the same as everyone else!

BackPacker
14th Jan 2008, 21:02
You have to know the plane and all its systems before you get airborne.

You just made me realise again how long it's been since I flew the DA-40 TDI.

- Power lever MAX
- Switch from ECU Auto to ECU B
- Switch to alternate air intake

beeped
15th Jan 2008, 00:33
With the DA-40 there's even time to pull out the checklist AFTER your engine has failed :}

IAS - 75kt
Power Lever - MAX
Check Annunciator Panel
Check Ts & Ps
Check Fuel
Check Emerg. Fuel Xfer - Normal
Fuel Xfer Pump - On
ECU - ECU B
Engine Master OFF/ON
ECU Auto

Still no engine? Just mush down at 500ft/min :p

SNS3Guppy
15th Jan 2008, 06:03
The answer really depends on the aircraft and the powerplant, and the circumstances. No matter what you're doing, if you're flying visually, once the engine starts running rough isn't the time to start deciding when and where to go. What to do is decided before you ever strap in for the flight, and where to go is a second-by-second decision you make every moment of the flight.

The year before last I experienced a rough engine in a single engine tailwheel airplane at about 300 AGL over a heavily wooded mountain forest area. I took steps to ensure the engine was running; made sure it had every chance to have fuel and spark by verifying the ignitors were on and the fuel boost pump was on. I pushed the speed lever (for that engine) up, and prepared to make a forced landing. the engine was surging badly, from idle to about 75% power. I followed a road off the mountain, keeping it under me until I reached a rural airport about ten miles away, where I landed.

About three months later I experienced another power loss in a similiar airplane at about 150' as I exited the bottom of a steep canyon, and made a forced landing on a hillside.

Be prepared, but do that preparation before you ever leave the ground. Then use that preparation every moment of every flight. The life you save, among others, will be your own.

ShyTorque
15th Jan 2008, 07:01
Don't forget to look for a school to narrowly miss. The media will love you for it.

Final 3 Greens
15th Jan 2008, 07:37
You are flying around on a nice VFR day and the engine suddenly starts to run roughly - what would you do?

First apply the POH actions for rough running engine on that type.

To answer further, need to know

What altitude

What is the fuel state

What track I am making good?

What is the wind direction/speed

What weather conditions (nice VFR day is pretty vague - if its -20 degrees it may skew the decision)

Over sea or land

If sea, are there ships nearby

What is the sea state

if land, what type of terrain

How close is nearest populated area

How near is nearest usable airfield?

Any physical signs of why engine rough - e.g. oil or smoke?

Depending on the answers to the above, I might consider a number of decisions

FullyFlapped
15th Jan 2008, 09:11
Well, at the very least I think you ought to tell one of the cabin crew when you order your next GnT ... :cool:

fireflybob
15th Jan 2008, 09:19
Thanks for all the fantastic replies guys - what a lot of experience there is here! Final 3 Greens asks a lot of relevant questions and having applied the POH actions for rough running engine on that type it then depends on the situation.

I am assuming we have a single engined aircraft but another consideration would be to point the aircraft towards the nearest suitable aerodrome and gain height if possible. When overhead said aerodrome close the throttle and perform a forced landing procedure. If the engine is running rough it might quit completely whilst performing a normal join where you might not be within gliding distance of the runway.

englishal
15th Jan 2008, 09:53
There was an interesting article in the US AOPA mag about Engine Failure At Take Off situations. It could be applied to EF at any altitude but likely your speed will be higher.

The first thing that should come as an automatic response is to unload the wings.....push forward hard. The article makes a point of stating how much you actually have to push, and the amount of horizon which fills the screen - it varies for each aeroplane but rule of thumb is that you go from 2 thirds sky filling the screen (on climb out) to 2 thirds ground filling the screen (at best glide).

The reasons for this are (amongst others)
a) when the wings are unloaded in the push over, nothing bad like stall / spin can happen and it gives some extra time to think about things. A pilot faced with EFATO is likely to be caught off guard and an automatic response like this could save a life or two.
b) You need to increase airspeed by sacrificing height, there is no other way around ;)

Good article......

fisbangwollop
15th Jan 2008, 10:25
I notice not many of you mention a quick call to ATC!! even if you are not talking to ATC how about 7700 on the transponder, at least then when you drift down below radar coverage your last known position will be left on any radar that was seeing you!! Little point in making a safe survivable landing over hostile terrain ( The Scottish highlands) only to die of exposure on the top of a 3000ft mountain!!

Mike Cross
15th Jan 2008, 10:50
In my case it was carry out the normal checks and divert to the nearest a/d. I was en route Popham to Henstridge and talking to London Inf so I told them what was happening and that I was diverting to Compton Abbas. They asked if I wished to declare an emergency, which I declined. CA was in sight so I switched to them explained the problem and they cleared me straight in for an uneventful landing.

The problem was a drop in RPM and an increase in vibration. Drained the gascolator to check for water and/or debris. Unable to reproduce the problem on the ground despite extensive checks so eventually took off without incident for return to Popham.

About 5 mins after departure it happened again. I established that a slight power reduction caused it to go away and opening it wide caused it to reappear after a minute or two. With Bowerchalke, Old Sarum, Middle Wallop and Chilbolton all along my track plus plenty of fields it wasn't a crisis.

After about 3 days and lots of running the engineers ran it to ground as a valve guide breaking up. Most of the time the valve seated fine and compressions were normal but clearly at high power settings it was vibrating out of alignment, the valve wasn't seating properly and she was only running on 3 cylinders.

Your question doesn't give enough information for a sensible answer. Running rough? The Beagle Pup I used to fly did that. The answer was simply to turn it the right way up again, whereupon the problem went away.:E

fireflybob
15th Jan 2008, 11:01
Your question doesn't give enough information

Deliberately so, my dear chap!

tmmorris
15th Jan 2008, 11:19
The only time so far I've had an engine failure I solved it in two seconds...

I'd turned the fuel to OFF instead of Right.

Which is why PA38s have a button you have to push to turn the fuel off - otherwise it will only go on Right or Left. A feature which long ago should have found its way into the PA28, if you ask me.

I nearly had a heart attack, though.

Tim

fireflybob
15th Jan 2008, 11:38
Which is why PA38s have a button you have to push to turn the fuel off - otherwise it will only go on Right or Left. A feature which long ago should have found its way into the PA28, if you ask me.


All the PA28s I have ever flown have a catch to help prevent inadvertant turning of the fuel selector to the OFF position.

BackPacker
15th Jan 2008, 11:40
I was on my first ever flight in a Robin DR200-160, after having flown the -120 and the -135CDI, and the R2160. But all of those had a single fuselage fuel tank, while this -160 also had two ferry tanks in the inboard section of the wings. We had flown on left for a while, then on right, and the remainder of the flight was to be on the main tank. So I twist the fuel selector to, what I thought, was the "main tank" position (arrow pointing forward). As it turned out, this was the "off" position. Arrow pointing backwards was the main tank.

Isn't there some sort of certification requirement that specifies that knobs, selectors and such, to the extent possible, should have "up" or "forward" meaning "good", "fly", "go faster" and "down" or "back" meaning "bad", "stop", "land", "go slower"? Plus, if you want to do something that might be really stupid in-flight (such as shutting off the fuel completely), shouldn't there be some sort of guard so that you cannot do this by accident?

Fortunately the pilot who accompanied me spotted my error in time.

tmmorris, the PA28 does have a little guard built-in into the fuel selector so that you cannot accidently turn it off. In fact, the first time you deliberately want to turn it off (on the ground) you've got to look carefully at how to place your fingers so that you can push the guard out of the way and turn the selector at the same time. At least, this is on all the PA28s I have flown (so far the -161 model only).

Mike Cross
15th Jan 2008, 12:05
Dunnit as well!

Beagle Pup has the fuel cock on the floor in front of the seat squab. Tapered pointy thing on top. Point it in the direction of the tank you want or forward for both, rearward for off. Needless to say I'd switched form "Left" to "Both" but had ended up with it pointing backwards rather than forwards.

One of the reasons not to change tanks near the ground or immediately before take-off or landing.;)

SNS3Guppy
15th Jan 2008, 16:39
Isn't there some sort of certification requirement that specifies that knobs, selectors and such, to the extent possible, should have "up" or "forward" meaning "good", "fly", "go faster" and "down" or "back" meaning "bad", "stop", "land", "go slower"?


No. You'll find quite a disparity between makes and models, and even the same type aircraft from the same manufacturer where different customers have different requests. In some cases, the switch positions can be exactly opposite...even on the same model aircraft.

Plus, if you want to do something that might be really stupid in-flight (such as shutting off the fuel completely), shouldn't there be some sort of guard so that you cannot do this by accident?


Not necessarily. Otherwise we'd have a lock on the mixture (some have a quasi-lock with a vernier control, others a simple metal tab, others none). Locking out the fuel shutoff could hurt or kill you in an emergency.

The first thing that should come as an automatic response is to unload the wings.....push forward hard. The article makes a point of stating how much you actually have to push, and the amount of horizon which fills the screen - it varies for each aeroplane but rule of thumb is that you go from 2 thirds sky filling the screen (on climb out) to 2 thirds ground filling the screen (at best glide).


This is unnecessary in an engine out or in a stall condition. The aircraft will continue to descend at it's trimmed airspeed, in fact. In most light airplanes, your climb speed is very close to your glide speed. If you're trimmed for the climb, you're trimmed close to the glide. In general terms, your best glide speed will closely approximate your sea level best rate of climb speed (Vy), and your minimum sink glide speed will closely approximate your sea level best angle of climb speed (Vx). If you're trimmed for one of these speeds on the climb, a power loss will result in a trimmed descent at that speed if you don't get involved (i.e. pulling back and interfering with the airplanes ability to do it's job...remain stable).

Inexperienced flight instructors scare students by teaching agressive pushing in stall training; it's not necessary. The difference between stalled and not stalled is less than a degree in angle of attack...something you can't see. If you're holding back pressure to stall the airplane during practice, for example, very slight relaxation of the back pressure is all it takes, and you can recover easily enough with the nose on the horizon...no need to fill the windscreen with sky, or ground for that matter. Likewise during an engine failure; you're entering a glide, not divebombing the enemy. Don't get in a rush to be too agressive with anything.

So far as preventing a spin...that's preventable by continuing to fly the airplane. Don't let it spin. Airplanes don't spin on their own...they need to be shown the way. Don't do that.

bjornhall
15th Jan 2008, 20:26
Slight roughness, gradual onset, no power decay?
- Check magnetos L/R, if significantly worse on either, suspect fouled plugs. Lean to proper cruise setting, wait for plugs to unfoul themselves (should take a couple mins). Would head for an airport or at least fly to/remain over suitable terrain for a forced landing at this stage while waiting for the plugs to clear, "just in case".

Sudden onset of significant roughness, or as above but didn't clear after a few mins?
- Check magnetos L/R, if significantly worse (or engine stoppage) on either, suspect magneto failure. Procede to nearest suitable airport; use single magneto if needed.

No change with magnetos L/R?
- If manual alternate air available, pull it.
- If fuel pressure fluctuations (check "fuel flow" gauge), fuel pump on.

None of the above solved it?
- Something's the matter; procede to nearest suitable airport while remaining over suitable terrain. Vary mixture, trying to find a setting that minimizes roughness (if that results in an unusual mixture setting, something is still the matter).

ATC?
- If I need their help for any reason (my prefered route takes me through controled airspace, I'm out over the sea and need to be rescued in a hurry if the engine was to fail, or some such), make a Pan Pan call.

That's how I'd do it!

Maoraigh1
15th Jan 2008, 20:55
I've read of a leaking carb float causing too rich rough running. Carb heat warmed the air in the float, causing expansion, which pushed fuel out, restoring float buoyancy, and engine ran O.K. This lead to carb ice being assumed to be the problem. Cold air lead to contraction of the vapour in the float, and more fuel entered the float, until the mixture was so rich the engine lost too much power for the aircraft to remain in flight. The pilot made an off-airfield landing, blaming carb ice.
Would leaning the mixture work with a sinking carb float?

SNS3Guppy
15th Jan 2008, 21:45
I've read of a leaking carb float causing too rich rough running. Carb heat warmed the air in the float, causing expansion, which pushed fuel out, restoring float buoyancy, and engine ran O.K. This lead to carb ice being assumed to be the problem. Cold air lead to contraction of the vapour in the float, and more fuel entered the float, until the mixture was so rich the engine lost too much power for the aircraft to remain in flight. The pilot made an off-airfield landing, blaming carb ice.
Would leaning the mixture work with a sinking carb float?


Sounds good on paper. However, the carburetor heat doesn't come near the float, and doesn't warm it; carb heat is used to adust the tempeature of the induction air...not the carburetor, not the float bowl, and not the float. The float is sealed, not full of fuel, and the temperature of the float doesn't make any difference in it's ability to function. Regardless of it's temperature or that of the fuel, it should always float. The function of the carburetor float is only to stop fuel flow into the float bowl, when it reaches a predetermined level, and it does this by action of a needle valve actuated by the float. The float bowl, in turn, only serves as a holding resorvoir, a small "header tank" if you will, which supplies the main and idle jets.

Worse case senario, you have a float which fails and leaks...preventing it from floating on the fuel and shutting off fuel flow to the carb float bowl. The carburetor floods out.

A certain amount of air above the fuel in the float bowl is required, as the main jets work based on differential pressure between the carb throat venturi, and ambient air pressure/fuel pressure...the ambient pressure supplied by venting the float bowl. Flood it and you can have an engine stoppage, or supply enough fuel uderpressure adn you can flood out the carb and engine...and have either a fire or an engine failure.

Can you prevent it by leaning the carburetor? Possibly, but don't count on it. You can go to cutoff on the mixture and still have a fire hazard or flood problem. Where it's usually noticed is when you approach the airplane to preflight...the float has sunk and you'll see fuel leakage down the nosewheel or through the bottom of the cowl, with stains or wet goo present depending on the nature of the leak, the ambient temperature, etc. In flight, you're not going to know the float has sunk; you may have a rough engine, you may not.

SoundBarrier
16th Jan 2008, 00:56
I had the engine in a C182 do horrible things once, it surged twice and then stopped making noise. I managed to get the engine going again, but as said before...

Step 1 :- Profanities.
Step 2 :- Procedures as per the POH

If the rough running does not go away, I would start with the mags and then move onto the fuel. Just remember, when playing with the fuel it can take a little while for some fuel to come through if you've run a tank dry or had an issue with a lack of fuel for some reason.

kiwi chick
16th Jan 2008, 01:23
SoundBarrier, you beat me to it! ;)

From experience:

1) Say "fcuk"
2) Carb heat
3) Mag check
4) Fuel - check pressure & tanks
5) 7700
6) land

(I got priorty cleared to land at wellington, no less than three Air NZ planes lined up waiting to enter and roll while I trucked on in in my little PA-28... :} I still remember one of them responding to ATC's "hold at Alpha for light aircraft on priority" with "What??" :D )

SoundBarrier
16th Jan 2008, 01:29
Kiwi Chick :-

For more detail -

1) "Oh, Fcuk!" (Turns to pax and says, "No everythings fine, just a little glitch!)
2) Push and pull levers and switches and things while sweating like a sprinkler at 500PSI
3) No change
4) "Oh, Fcuk -Fcuk"
5) Eat part of your chair with your buttocks (I didn't know I was THAT hungry)
6) Engine roars back to life - "I Love you plane!" you scream, with your pax looking rather perturbed
7) Land safely at nearest airfield - taxi direct to pub to consume much alcohol.
8) It's almost midnight and you go back and help your pax out the plane 'cos you forgot they were there!

kiwi chick
16th Jan 2008, 01:39
http://i181.photobucket.com/albums/x105/kiwiflygirl/PMSL-1.gif

"I Love you plane!" you scream

:D That is so funny!!!

I was asked by ATC if there was anything they could do to help. (WTF??? Are they gonna come up here and check the engine??)

I said "yes thanks, have a bourbon waiting for me when we land".

But they didn't find it half as funny as I did (in my fear-induced delirious hysterics)

SoundBarrier
16th Jan 2008, 01:43
Yeah ATC do loose a sense of humour at times, bless 'em. My best was when a newbie controller at a local field lost the plot with 11 planes in the circuit 5 of which were on final, hi pipes on the airwaves and says...

"All aircraft on final....SCATTER!"

Everyone assumed an uncontrolled airfield for the next 30 mins, it was so funny! Everyone was giggling on air!

kiwi chick
16th Jan 2008, 01:48
Hahahahahaha!! What airfield was that? :}

SoundBarrier
16th Jan 2008, 01:52
FVCP - But many years ago. :E

llanfairpg
16th Jan 2008, 09:45
Bob--as you are one of the most experienced pilots and instructors on here my action would be to say

"You have control"

fireflybob
16th Jan 2008, 09:47
Bob--as you are one of the most experienced pilots and instructors on here my action would be to say

"You have control"

I like your style!!

First_Principal
16th Jan 2008, 09:57
In case it helps anyone else I had just this scenario (rough running, losing power etc) in a small Cessna. It was a little irregular insofar as it would come and go a bit and the rough running itself wasn't constant :uhoh:.

Being a bit of a spanner I could tell that as it wasn't regularly missing it was less likely to be ignition. This was more of a 'feel' thing but FWIW the logic is that a fouled plug or failed valve/piston/cylinder would be more likely to have a regular miss than say carb ice. If you want an example try pulling a plug lead off a running 4 or 6-cyl car engine sometime.

Anyway I did the first thing one should do and pulled the carb heat, miraculously it made quite a difference ... for a short period of time after which the problem returned. Bearing in mind this was a hot, dry, day with temp/dewpoint miles apart (I checked!) it seemed rather unlikely to be real icing but I ran with that view for a bit.

After a while (probably not that long although it seemed ages) I decided it was more likely to be a mechanical problem with the carb and/or air intake. Careful manipulation of the carb heat control would restore the engine for a period of time, after which it would return to the original problem. At times I had to mess with it continually, other times it would operate ok for several minutes.

Given I was some distance from a 'drome, over rough(ish) terrain, or sea, I elected to continue on rather than attempt a precautionary landing. It would have been do-able, if necessary, in some places but at its worse the engine would run a max of 2200/2300 rpm (with EGT vy hot) which was enough (just) to maintain a couple of thousand feet.

Incidentally I also checked the fuel tap was in the correct position and tried running on individual mags once I'd established an ability to keep going, at least for a bit. What I didn't do was mess with the mixture, my logic being that I didn't want to play with anything more than was necessary - especially carb related - in case I exacerbated the situation and/or introduced another problem.

Eventually I landed and a subsequent check showed that the carb intake flap select lever cable clamp had become loose meaning that the engine was in fact alternating between full carb heat to normal air intake and something in between from time to time. By moving the carb heat control I was occasionally able to move the flap when the clamp momentarily grabbed.

The crunch to this long-winded tale is in the decision-making really, IMO. Not every situation is the same and, if possible, some logic should be brought to bear on the issue. If the fan stops completely then between soundbarrier & k1w1 chick you've got it mostly covered <grin> but if it's still running, albeit roughly, then there could be other options. Most important, methinks, is to DO ONE THING AT A TIME, and, if possible, give that action a few moments to see if it makes a difference. If it is icing carb heat won't necessarily work immediately, in fact it could even become worse momentarily, likewise changing tanks or whatever could take a few moments to make a difference. The main thing is not to panic (yeah :rolleyes:) and start pulling and pushing things haphazardly. If in the end nothing works and you've insufficient power to keep in the air then you better go through the drill and pick your landing spot smartly, however if you are able to keep it going, at least for a bit, it widens your options considerably - at least insofar as where you're going to land. This could make all the difference, particularly if you're over inhospitable terrain.

No doubt there's other things I could say from this experience, I'm not convinced myself that I made the right decision :suspect: - perhaps I should have landed immediately, perhaps I should have tried the mixture too (theoretically at least it may have helped), but I've lived to tell the tale which has allowed me to ruminate about the situation somewhat. I don't think I'll ever quite reach a conclusion, mostly in fact I think I didn't do quite what I should have, but I'm not sure if thinking this would actually help another time because the chances are it would be a different situation with different parameters to deal with. So perhaps the moral of the story is to by all means follow the drill but don't do so blindly, do it deliberately. Particularly if you've height and/or partial engine in hand try and think things through both in terms of what you're about to do and if perhaps you (or pax!) have just recently done something that may have introduced the problem...

Finally, once down, don't be afraid to make an arse of oneself on proon and tell all - it could well help someone else one day as could (some of!) the subsequent comments. Bring 'em on :}!

ShyTorque
16th Jan 2008, 12:31
Beagle Pup has the fuel cock on the floor in front of the seat squab. Tapered pointy thing on top. Point it in the direction of the tank you want or forward for both, rearward for off. Needless to say I'd switched form "Left" to "Both" but had ended up with it pointing backwards rather than forwards.
One of the reasons not to change tanks near the ground or immediately before take-off or landing.

Yes, I visited EMUAS where I used to instruct and asked where "my" Bulldog was. The ground crew chief led me by the arm to a pile of metal at the back of the hangar.... a AEF pilot got the fuel selection badly wrong and the engine stopped during the climb. :sad:

fireflybob
16th Jan 2008, 16:10
Of course it's always possible to turn selectors in the wrong direction even when safety devices are fitted.

However when you turn the fuel selector "OFF" after engine shutdown you are practising how to do so (as well as ensuring that it is physically possible to select "OFF"). It seems to be the practice of some operators to leave the fuel selector ON after shutdown, unless perhaps it is the last flight of the day.

I have flown with some pilots on the PA28 who were not aware of how to turn the fuel selector to the OFF position because there were not used to turning the selector to the OFF position.

llanfairpg
16th Jan 2008, 16:22
Exactly our thinking on the C152/0. I have even see fuel cocks drilled and wire locked on!!!!!

fireflybob
16th Jan 2008, 16:29
Exactly our thinking on the C152/0. I have even see fuel cocks drilled and wire locked on!!!!!

Yes sadly I have come across that too!

mm_flynn
16th Jan 2008, 17:21
If you're trimmed for the climb, you're trimmed close to the glide. In general terms, your best glide speed will closely approximate your sea level best rate of climb speed (Vy), and your minimum sink glide speed will closely approximate your sea level best angle of climb speed (Vx). If you're trimmed for one of these speeds on the climb, a power loss will result in a trimmed descent at that speed if you don't get involved (i.e. pulling back and interfering with the airplanes ability to do it's job...remain stable).Are you sure? (EnglishAl's post, to which the quoted response was specifically related, was highlighting the need to be aggressive in establishing the nose down glide attitude in a sudden engine failure on take-off (not just a bit of rough running).)

To be more specific, I understand the point that you are trimmed for an AoA so the change in excess power from positive to negative should over time result in the same airspeed but a sink rate rather than a rate of climb.

BUT, with a sudden lack of power, the aircraft flight path needs to move from say 6 degrees up (750 fpm climb @ 75kts) to 6 degrees down (typical 1 in 10 glide ratio), which it will do pretty quickly, but the airframe needs to rotate the same 12 degrees at the same rate that your climb moves to descent (i.e. fast) otherwise your AoA will be temporarily increasing, increasing drag, loosing airspeed and sapping energy out to rotate the aircraft.

All of this added to the fact that until you are level, part of the lift vector is slowing you down and you need to get most of the way through the rotation before you have eliminated the deceleration from drag, induced drag and the rearward component of lift.

llanfairpg
16th Jan 2008, 17:53
Amazing, and I just thought it was Bernoulli's theorum.

Incredible what goes through pilots minds when faced with rough running.

ShyTorque
16th Jan 2008, 17:59
Exactly our thinking on the C152/0. I have even see fuel cocks drilled and wire locked on!!!!!

:eek: Presumably a pair of sidecutters was provided for use in the case of an engine fire?

llanfairpg
16th Jan 2008, 18:02
The wire was low strength! I know because the CFI used to go mad when someone broke it to turn the fuel off!

SNS3Guppy
17th Jan 2008, 04:41
Are you sure?


Yes.

So far as a need to scream, panic, or fear a rough or failed engine...you're flying an airplane with wings. It doesn't depend on an engine to fly. That's why it's not an engineplane, but an airplane (or "aeroplane" if you happen to breathe aero). You flew it up there, fly it back down.

Agressively manhandling the airplane isn't required to fly it back down.

airmuster
17th Jan 2008, 05:11
After having read most of the posts here, for which I concur on most of the advice given. For me, I am always looking for suitable landing areas as flying at below 500 for most of my career demands it.
However, one interesting aspect I have come to notice in training our new PPL pilots today (in OZ anyway) is that they are taught to land with power mostly on, and to do longer approaches. I realise that this somewhat alleviates the problem of an engine misfiring due to carby conditions or such like, but if the engine does konk then ...... well....... sorry about the bent a/c.
What happened to doing glide approaches. Its safe, teaches a hell of a lot re a/c performance in lots of different circumstances, and it may save your life and those of others one day (esp if you happen to want to put down in a school playground)
Sure when you get into larger a/c, I can understand the need of keeping a brick aloft with brute power, but for most single piston engined............
My cents worth:)

mm_flynn
17th Jan 2008, 09:22
Yes.

So far as a need to scream, panic, or fear a rough or failed engine...you're flying an airplane with wings. It doesn't depend on an engine to fly. That's why it's not an engineplane, but an airplane (or "aeroplane" if you happen to breathe aero). You flew it up there, fly it back down.

Agressively manhandling the airplane isn't required to fly it back down.

Barry Schiff's argument seemed quite persuasive, that a positive control input was critical in an EFOT, so I guess I will have to go and try it. 'It' being, at a safe altitude chopping power to idle when trimed for a Vy climb and see if I stall or just nicely transition to a good glide descent.

llanfairpg
17th Jan 2008, 12:13
Rough running, the title of the thread dosnt need aggresive handling but it does need decisive handling and looking at the posts I cannot see much evidence of any methodical plan, more throwing in a couple of thoughts that might help.

Knowing Bob as I do and knowing his meticulous detail I have a feeling he is waiting for the correct moment to publish his easy logical series of actions.

kiwi chick
18th Jan 2008, 00:02
Airmuster... oh if only you were here a few weeks ago - there was a very enlightening thread on the pro's & con's of teaching and/or doing glide approaches. :ok:

SNS3Guppy

You flew it up there, fly it back down.

Well, I like your logic here. And I'm not normally one to argue. :E

But when your rough running occurs EXACTLY midway across cook strait, altitude due weather prevents you gliding to either shore, then scream & panic & swear is not the FURTHEST from one's mind.... :ok:

(I think it comes a close second to: jaysus that's gonna be freezing, and did I just see a SHARK?? :eek:)

John Hill
18th Jan 2008, 00:23
(I think it comes a close second to: jaysus that's gonna be freezing, and did I just see a SHARK?? :eek:)

Followed soon after by "just where is that ferry"?

kiwi chick
18th Jan 2008, 01:05
Haha, yes...........

Funny how there's never one around when you need it. :\

Or how willing your pax are to point out all the dark shadows lurking under the water... :eek:

Runaway Gun
18th Jan 2008, 01:30
HA! I employed the same technique whenever my students flew me out too far over the water. I'd crane my neck around and say "Look of the size of that shark. Is that a Mako or Great White?" Suddenly the aircraft would deviate closer to within gliding range of land...

Final 3 Greens
18th Jan 2008, 03:42
looking at the posts I cannot see much evidence of any methodical plan

You cannot assemble a credible, never mind methodical plan with the lack of data in the original question.

fireflybob
18th Jan 2008, 22:24
Knowing Bob as I do and knowing his meticulous detail I have a feeling he is waiting for the correct moment to publish his easy logical series of actions.

llanfairpg, I wish!

My observation is that many replies focus on the procedural aspects of addressing the rough running engine. I was interested to see how much emphasis was put on pointing the a/c (I am assuming single engine) towards the nearest suitable aerodrome and (if possible) gaining height before executing a forced landing from the overhead.

As various posters have indicated there are a lot of variables, hence no strictly right answer - my question was deliberately vague - I wonder who taught me that...............

llanfairpg
19th Jan 2008, 18:28
Yes, virtually no one mentioned gaining altitude and I think only one mentioned surface wind considerations.

Vague questions provoke more thought and yes I know who taught you that!

Miss FM at Humberside too!