C172. Engine fire in flight procedure

[double_barrel]

The POH and my instructor say:

1. Mixture to idle cutoff
2. Fuel selector to OFF

But I read somewhere that leaving the engine running could potentially burn off fuel in the system that would otherwise add to the fire, so if the engine is running better to turn off the fuel but leave the mixture alone. That makes a lot of sense to me.

Any thoughts? If I was able to defend this procedure to an examiner, would it be acceptable?


Thanks

[Pilot DAR]

If you have a flooded carburettor fire during start (which I was right seat for once) keep cranking, get it running, and pull the fire through the engine, where it will do the least harm. Once the engine has run for a minute, shut it down, and have the induction inspected for possible damage.

A fire in flight will not be an induction fire, as the engine is running. In the case of any fire, remove the fuel, then oxygen, and heat, if possible. In the case of an engine fire in a 172 in flight, you only have control of fuel, so turn it off (mixture and fuel selector). There is only a small amount of fuel available to burn forward of the fuel selector, so don't worry about that. You're headed down then, so just focus on a good forced landing, there's little to burn dangerously up front, if the fuel has been turned off.

[A and C]

Wise words from Pilot DAR.

[double_barrel]

Thanks. While we are on the subject, I am being taught to use a viscious side slip at >80Kn to direct the fire away from the aircraft (ie if the fire is on the left, apply left rudder plus right aileron) and to loose height fast. This makes sense to me and is a lot of fun to practice, but it is not mentioned in the POH or anywhere else that I have looked. Any comments? Can I realistically expect to see on which side a fire is seated?

[Pilot DAR]

Sideslip away from a fire is more a multi engined airplane thing. Sure, if you have a fire in a single, and you think a sideslip will lessen your problem, go ahead. Otherwise as log as you are thinking that could be a possible course of action, the training objective has been met!

[Jan Olieslagers]

It does correspond to the little bit of teaching I received: fly as unstraight as possible, to take the fire away from the humans aboard. Actually it would seem to me more relevant with only one engine, positioned straight before the cockpit. as must be the case for the vast majority of us.

[B2N2]

That really seems like an over the top technique.
we’re not talking Messerschmidt and Spitfires here.

[flyingorthopod]

I've never understood why ga aircraft don't have engine bay extinguishers. Race car extinguishers with pull handles are cheap, fairly light and very simple.

[B2N2]

Because everything adds weight and everything costs money......but mainly because it’s not required.
There are also not enough occurrences to warrant it.
we’re not talking engines running at or past their design parameters with rapidly changing loads....like race car engines that are only expected to last one race before rebuilding anyway.

To the original poster ‘double_barrel’ :
Examiners will and should take a very dim view of applicants making up their own procedures.
You shouldn’t. Neither should your instructor.
Unless it’s in a manual from the manufacturer or a publication from an official aviation source it’s a technique and as such subject to opinion.
At this stage of the game you lack the insight and experience to tell correct from tribal law and superstition.

Think about this for a moment:
A C172 does not have complicated electric, hydraulic, pneumatic or fuel systems.
No multiple hydraulic pumps increasing pressures to 3000 psi while heating hydraulic fluid to boiling points.

In a light GA airplane you can have three types of fires: electrical, fuel or oil.
Fuel off and mixture cutoff will starve a fire quickly.
Oil you cannot shut off but if you have a big enough leak for the oil to combust on a hot exhaust then you’re out of oil pretty quickly.
The cowling will contain most of the flames and if it does burn through the cowling you have 65-70mph ( best glide) wind for a fire to deal with.
Again, there is no system like high pressure fuel pumps or hydraulic high pressure pumps to sustain a fire.
Keep in mind where the fuel is in a light GA aircraft....the wings.
You’re probably more likely to get an electrical fire in your wings because of bad wiring then an uncontained engine fire that would I require you to sideslip the flames to where you hold the fuel.

i know that’s what your instructor told you.
They're not always right.

[Pilot DAR]

i know that’s what your instructor told you.
They're not always right.

Unfortunately, this is more true than I wish it were. Some people (in any industry really) make themselves more important by inventing or extrapolating information, and imagining scenarios which are remote, yet apparently need great thought and planning to overcome. Engine fires in light singles, particularly with no fuel pumps, are very very rare. In my 4 decades of flying, I know of one, and that was a fuel line left loose on a Cessna 206 which ignited about the time that the pilot opened the throttle. He realized he was on fire at about 100 feet, landed back onto the lake, and stood on the float waiting for help (he coulda jumped in, but help came before he could not stand on the float. Interestingly, the fire extinguished once the fuel pump was turned off, and the fuel valve closed. Though there was cabin smoke damage, on the engine compartment was fire damaged.

Yes, thing about fire, learn the published procedures, and leave it at that. Thereafter, as you are taught, ask for references to the procedures you're being taught (nearly all should be in the flight manual, which you really should read cover to cover anyway. If an instructor is asserting procedures which are not in the flight manual, ask why. What is the authority for those procedures. Though flying instruction generally follows the standards and lesson plan, I have seen some ideas come from other pilots which had a poor basis in reality. Piloting has been around long enough, that if it's important, it's written down by someone authoritative!

[Auxtank]

You've answered your own question DB.

Add a

3) Get looking out the window, smartish, instead of doing supposed Merlin techniques to quash the flames, to form your plan early for entry to a big flat field.

And as PilotDar says; published procedures rule! Then YOUR plan (based on your observations out the window), then keeping the two of those things in harmony 'til the wheels come to a stop.

[double_barrel]

You've answered your own question DB.

Add a

3) Get looking out the window, smartish, instead of doing supposed Merlin techniques to quash the flames, to form your plan early for entry to a big flat field.

And as PilotDar says; published procedures rule! Then YOUR plan (based on your observations out the window), then keeping the two of those things in harmony 'til the wheels come to a stop.



Indeed as PilotDar says elsewhere, the POH does not list basic airmanship, and in the event of engine fire or engine fail, it is being hammered into me that action 0 is set the glide speed and select somewhere to land.

I am puzzled that I am being very explicitly taught something that is not in the POH and that you guys tell me does not come under obvious, basic, 'airmanship'. I presume the school is familiar with the examiners' expectations. I will ask more when I am next there. Regardless, it is fun and instructive to set a fast glide at 3,000' AGL and fly a fast and controlled descent with the controls crossed. I think it has helped my flying a lot and made it easier for my brain to manage cross-wind landing and takeoffs. In fact, I am loving the whole engine off flying thing, it takes me back to sailing skills where you cannot just power your way out of a situation but need a long term and accurate planning.

[Pilot DAR]

I imply that DB is saying that the instructor is training to slip for an engine fire in a 172. While not no, I can't find that procedure in any of the six 172 flight manuals I have reviewed with this question in mind. What I do find, is that from as far back as the 172N, Cessna does state that for a wing fire, to slip to keep the flames away from the fuel tank and cabin. Now, aside from fuel, I can't imagine what in a 172 wing is going to burn enough to notice, but okay, Cessna wrote a procedure, so that's what you do.

But let's dissect Cessna's procedures here: For an engine fire, shut down, and isolate the fuel. For a wing fire, side slip, but there's no mention of shutting the engine down! So it sounds like the instructor is mixing together two different procedures! Perhaps (and I'm speculating) Cessna thinks it's too much to expect a pilot of a 172 to perform a viscous slip with an engine on fire while gliding, so they want the pilot to focus on a good gliding forced landing. And, they're content for you to slip with a running engine for a wing fire. As well as being experts on their planes, Cessna are also experts at evaluating "average" pilot skills, and avoiding presenting needlessly complex or task saturating procedures. They will write what needs to be written, though will very certainly avoid writing more than is needed.

So, when the instructor presents a procedure for slipping for an engine fire, pull out the flight manual, and have a read (again, 'cause you've already read it a few times, right?;) ) . Look up engine fires - no procedure stating a slip, but look.... a page later, slip for a wing fire! You instructor is required to instruct you in accordance with the flight manual procedures, not to mix and match them....

What we don't want is your faltering recollection during a stressful situation, to have you remembering to shut down the engine, and slip away from the flames when you have a fire, because if it were to be a wing fire, Cessna says you can leave the engine running, so why shut it down?

[Maoraigh1]

Would carb and injection engines be the same? eg. burst high pressure pipe in a fuel injection engine. I recollect a Cessna manual recommending high airspeed for an engine fire, but I haven't flown a Cessna for almost 9 years. Would engine rotation maintain the injection high pressure until the fuel in the pipes ran out? Was there a single Piper fire where the burning high pressure injection fuel sprayed over the outside of the cabin?

[Big Pistons Forever]

The good news is every incident report I have seen where there was an in flight fire, the fire went out as soon as the fuel and ignition were turned off. The ones that ended badly all involved no or incomplete engine shutdown procedures.

This is not rocket science. If you have an engine fire, shutdown the engine in accordance with the POH procedures and execute a forced approach to the best field within easy reach.

[B2N2]

C172SP fuel injected IO-360.
its ancient mechanical fuel injection fed by....an engine driven pump and an electrical pump for critical phases of flight.
So mixture idle cutoff - fuel selector off and no more fuel to a fire.

Don’t complicate things.

Unfortunately this is where instructors can damage their reputation and their believability suffers.
Don’t make up stuff that isn’t there.

Once had an instructor for a jet recurrent that had come up with a sim scenario that eventually had you turn off an electrical bus that powered the engine fire extinguishers and then he gave you an engine fire on an ILS below minimums.
We fell for his trap and landed with a fire we couldn’t fight.
Never mind the chances of these 6 steps ever lining up being 0.01 x 0.01 x 0.01 x 0.01 x 0.01 x 0.01 per 100.000 flight hours.

Possibility doesn’t equal probability in anything in life including mechanics.

An examiner will hold you to a well known and well published standard.
Every instructor has their pet peeves but made up stuff shouldn’t be one of them.

I was once called over and scolded by an examiner for teaching a student a technique which wasn’t in the flight manual and which he promptly demonstrated on his flight exam.
Lesson learned.

Now..I consider it very good practice to theorize about certain events and their likelihood and technique with fellow students, more experienced pilots and instructors and students.
Just a healthy enterprise and good exercise in systems knowledge and understanding.

Reviewing accident reports under guidance is another good way of learning.

[kghjfg]

I was taught that “sideslipping might help me see where I’m going”, I always presumed an oil fire would come with lots of oil, and that might be all over the screen by now. Sideslipping was mentioned, but nothing to do with the fire per se, to do with visibility.

I think the attitude was “here’s a tool, you might need it, see what happens to your screen if you do have an engine fire”.

To complicate matters further, the emergency descent I was taught was, 2 stages of flap, point the nose at the ground, stay within flap limiting speed. Does a “vicious side slip” get you down quicker, or is there a perception it might?

[India Four Two]

Does a “vicious side slip” get you down quicker, or is there a perception it might?

Side-slipping will get you down quicker and it should be practiced as a matter of course. I have often used it when I'm overshooting the touchdown area during a forced-landing practice. One piece of advice though - don't practice it when carrying non-pilot passengers. It scares them - ask me how I know! :)

However, side-slipping is not necessary to improve visibility. The view out the front during a glide approach is perfectly adequate.

[BigEndBob]

If the engine is on fire, you probably wouldn't see it as the air flow takes it under the aircraft.
On a stalling exercise i could see the prop was trying to stop every time we pulled the throttle to idle.
Then the engine lost some power when throttle pushed forward, so above a inversion we began to head back to the airfield.
Power slowly regained as we descended so thought it was a mixture problem.
Joined overhead then landed, as the aircraft rolled out the engine stopped but managed to turn off the runway. Bit annoyed with it stopping, i restarted it, then noticed grey smoke coming from the cowling. So evacuated the aircraft with extinguisher and fired into the engine cooling intakes. Later people commented about the four foot odd flames under the aircraft. Turned out to be a faulty carb. flooding. Was AD that hadn't yet been complied with.

I remember my old ex BoB instructor asking what i would do with an engine fire. He said you should pull back to the stall to stop the prop. before descending to stop fuel and oil being pumped out. Said he had seen many aircraft burn up by the pilot trying to blow the flames out. RIP Mike Edwards.

Also when dealing with an emergency, try to get someone else to do the navigation by asking ATC for QDM or radar vectors.
When i was above the haze, the ADF wasn't working and too much time was being used trying to twiddle VOR instead of dealing with the engine problem. The CAA in their wisdom have decided our airfield VDF not fit so can't be used. Shame worked very well for the last 20 years. Another safety item removed by the safety regulator.

[A and C]

I would guess there is about a pint of fuel forward of the fuel selector so once this is turned off there is very little to support combustion forward of the firewall unless you have had a major engine failure and then you have eight quarts of oil inside the engine to burn.

My advice would be to do the fire drill in the flight manual and fly a standard Cessna 172 forced landing just like you practiced in your trainning, the fire will have almost certainly burnt its self out by the time you get on the ground.

IMO the major risk from am an engine fire is getting the forced landing wrong and if you try any of the Spitfire techniques mentioned above the forced landing will take the average PPL into unknown territory and is likely to result in mishandling of the landing.

[double_barrel]

I'm loving the Spitfire techniques! I find that these things increase my confidence in 'free form' flying and understanding how the a/c responds, it is such a nice change from the endless series of highly standardised, routine manoeuvres I am making in training. Also it seems to me to be nice as a means of loosing height quickly while maintaining the flexibility of being flapless. And, as mentioned, I was previously finding it difficult to use aileron without tracking it with the rudder on cross-wind landings and takeoffs and playing with crossed controls and plenty of altitude has helped me to get over that.

Of course, I take all the points about not over complicating things and sticking to the manual. I guess it’s lucky that I have you lot to bounce these things off. Pre such forums and Youtube, I guess everyone's instructor was god, now they must be sick of being told 'that's not what this bloke on Youtube said' !!

[A and C]

It’s very difficult to post on forums like this as the audience is very wide and it’s difficult to pitch the advice at the correct level, clearly not all the readers are of sky god status so some sort of moderation has to be applied.

It therefore follows that any advice given should work for most of the audience most of the time. People may be able to sideslip aircraft into small spaces but this is the sort of technique if not trained and in practice results in low level spin entry with no chance of recovery and likely fatal consequences.

[Vilters]

Only one thing actually.
Close the Fuel Cut off valve ASAP and pull up to best glide speed.
Let the engine run to consume the little that is left in the carb and lines and die itself out of fuel starvation.

A fire needs fuel, oxygen and an ignition. => No fuel to burn, the fire will stop.

On sideslips.
KNOW your aircraft, KNOW your own capabilities with this aircraft.
- Some aircraft are prohibited for slips with flaps.
- Did you train on left and right slips? What altitude and speed.
- NEVER slip an aircraft without proper instruction.

- Set best glide speed and TRIM. => That way you only have to concentrate on direction with roll and yaw to you emergency landing field.
- Maintain best glide speed (do NOT pull or push on the stick-yoke but let the trim do its thing) and control sink rate and distance to emergency landing field with "S" turns.
- Know you altitude above ground level AT ALL TIMES.

And last but not least => NEVER go beyond your aircrafts and your own limitations.

[Pilot DAR]

- Some aircraft are prohibited for slips with flaps

Certified aircraft are not prohibited slips with flaps, the certification requirements state (my bold):

Sec. 23.143

General.

(a) The airplane must be safely controllable and maneuverable during --
(1) Takeoff;
(2) Climb;
(3) Level flight;
(4) Dive; and
(5) Landing (power on and power off).
(b) It must be possible to make a smooth transition from one flight condition to another (including turns and slips) without exceptional piloting skill, alertness, or strength, and without danger of exceeding the limit load factor, under any probable operating condition..................

And:

Sec. 23.177

[Static directional and lateral stability.]

(a) Three-control airplanes. The stability requirements for three-control airplanes are as follows:
(1) The static directional stability, as shown by the tendency to recover from a skid with the rudder free, must be positive for any landing gear and flap position appropriate to the takeoff, climb, cruise, and approach configurations. This must be shown with symmetrical power up to maximum continuous power, and at speeds from 1.2 http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/b1f2043f79fc1e4685256687006c31fe/SectionRule/0.424!OpenElement&FieldElemFormat=gif up to the maximum allowable speed for the condition being investigated. The angle of skid for these tests must be appropriate to the type of airplane. At larger angles of skid up to that at which full rudder is used or a control force limit in Sec. 23.143 is reached, whichever occurs first, and at speeds from 1.2 http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/b1f2043f79fc1e4685256687006c31fe/SectionRule/0.B64!OpenElement&FieldElemFormat=gif to VA, the rudder pedal force must not reverse.
(2) The static lateral stability, as shown by the tendency to raise the low wing in a slip, must be positive for any landing gear and flap positions. This must be shown with symmetrical power up to 75 percent of maximum continuous power at speeds above 1.2 http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/b1f2043f79fc1e4685256687006c31fe/SectionRule/0.12BE!OpenElement&FieldElemFormat=gif, up to the maximum allowable speed for the configuration being investigated. The static lateral stability may not be negative at 1.2 http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/b1f2043f79fc1e4685256687006c31fe/SectionRule/0.1948!OpenElement&FieldElemFormat=gif. The angle of slip for these tests must be appropriate to the type of airplane, but in no case may the slip angle be less than that obtainable with 10° of bank.
(3) In straight, steady slips at 1.2 http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/b1f2043f79fc1e4685256687006c31fe/SectionRule/0.2026!OpenElement&FieldElemFormat=gif for any landing gear and flap positions, and for any symmetrical power conditions up to 50 percent of maximum continuous power, the aileron and rudder control movements and forces must increase steadily (but not necessarily in constant proportion) as the angle of slip is increased up to the maximum appropriate to the type of airplane. At larger slip angles up to the angle at which the full rudder or aileron control is used or a control force limit contained in Sec. 23.143 is obtained, the rudder pedal force may not reverse. Enough bank must accompany slipping to hold a constant heading. Rapid entry into, or recovery from, a maximum slip may not result in uncontrollable flight characteristics. ...............

Someone is going to point out that some mid sized single Cessnas are placarded "Avoid slips with flaps extended". That's correct. It's not a prohibition, it's an "avoid". It warns the pilot that slipping with flaps could create instability. The aircraft still met the requirements for certification ('cause it was certified) but was less than ideal. The background is that the span of flaps of 172's, and 182's is such that in a slip, the wake off the outboard flap can impinge on the horizontal stabilizer, and upset the smooth airflow there. 150/150 do not suffer from this, as they have less span flaps. This is well described in the book "Cessna, Wings for the World" by Thompson, a former Cessna test pilot. In this book, Tompson writes that the aerodynamic deficiency was corrected in later models, but the placard was retained out of an abundance of caution. A little sad in my opinion, as a slip is an excellent means of controlling descent, once you're well trained to fly them within the aircraft's limitations, cautions, and with good airmanship.

Of course, an "avoid" placard should be carefully considered, and complied. But it is important to understand that it is not a prohibit, it's not an operational limitation. The wording in flight manuals, and warning placards is chosen very carefully ('cause of the lawyers), and must be considered by the pilot very literally - again, not a home made procedure, what the manufacturer says about flying the plane.

[horizon flyer]

I believe the avoid side slipping on a 172 comes from the older models with a 40 degree flap setting the newer models now have a 30 limit. Same with 150 40 max 152 30 max. The warning on some models which is not mentioned in the POH is don't open the throttle in the slip, always go back to balanced flight as some model will roll on their backs so fast you won't catch it. Happened to a site seeing C177 crossed controls for a good view pilot opened her up and she rolled in. On the 177 flap limit is 30 so it can be side slipped with them down.

Shut down as per the POH but I believe slipping away from the flames can be a good Idea fire walls don't hold up for ever.
In an oil fire if the engine can be stopped may be a good idea so on a VP pull to course pitch and slow down to stop the prop will reduce drag as well a bit more glide distance.
When I had an engine failure with oil smoke coming from the cowl no time as to low flight only lasted another 60 seconds.

[Pilot DAR]

Shut down as per the POH but I believe slipping away from the flames can be a good Idea fire walls don't hold up for ever

The standard:

Sec. 23.1191

Firewalls.

(a) Each engine, auxiliary power unit, fuel burning heater, and other combustion equipment must be isolated from the rest of the airplane by firewalls, shrouds, or equivalent means.
[(b) Each firewall or shroud must be constructed so that no hazardous quantity of liquid, gas, or flame can pass from the compartment created by the firewall or shroud to other parts of the airplane.]
(c) Each opening in the firewall or shroud must be sealed with close fitting, fireproof grommets, bushings, or firewall fittings.
(d) Removed and Reserved.
(e) Each firewall and shroud must be fireproof and protected against corrosion.
(f) Compliance with the criteria for fireproof materials or components must be shown as follows:
(1) The flame to which the materials or components are subjected must be 2,000 ±150° F.
(2) Sheet materials approximately 10 inches square must be subjected to the flame from a suitable burner.
(3) The flame must be large enough to maintain the required test temperature over an area approximately five inches square.
(g) Firewall materials and fittings must resist flame penetration for at least 15 minutes. .....................

So you should be okay for 15 minutes, according to the standard. If there's a pilot who can glide a 172 from a normal cruising altitude for more than 15 minutes, I want to fly with them, they would be an excellent power off pilot!

Humour aside, in the very remote chance of a fire in the engine compartment in a 172, turn the fuel off, and the hazard will be very greatly reduced. Engine oil is a very small risk. Now, for a turbocharged plane, the risks are increase a little. If a fire has been caused by turbo scavenge oil being blown onto the exhaust, that's bad. Then, yes, shut the engine down IAW POH procedures. I agree that stopping the engine will stop oil pumping, though a windmilling engine pumps much less oil internally. But, if the engine oil is being pumped into a fire, and you've shut it down, it may seize before too long, and then it certainly won't be pumping oil any more!

[India Four Two]

I hope that Pilot DAR’s extensive post has laid to rest the urban legend that Cessnas must not be slipped with flaps down. I have slipped various Cessnas (152, 172, 177, 182) with full flaps and have never had any problems. I routinely slip the 1970 182 (40° flaps) that I currently fly and it always behaves impeccably.

[Big Pistons Forever]

Following the thread drift re Cessna slips. Pre 1971 C 172's have a shorter dorsal fin and are more likely to show a tuck under and/or elevator pulsing. I have never experienced this in the later models only the early ones. That been said I teach the full flap slip is an emergency maneuver. Cessna's come downhill pretty well with full flap. If you are still too high even with full flap then instead of slipping you should go around and set up a better approach as the one you are on is outside an acceptable approach flight path.

[Pilot DAR]

We'll drift a bit to slips in a 172, as I think we've handled the topic of engine fires;

In his book "Cessna, Wings for the World", from which I quote, retired Cessna test pilot William Thompson writes:

"With the advent of the large slotted flaps in the C-170, C-180 and C 172 we encountered a nose down pitch in forward slips with the wing flaps deflected. In some cases it was severe enough to lift the pilot against his seat belt if he was slow in checking the motion. For this reason a caution note was placed in most of the owner's manuals under "Landings" reading "Slips should be avoided with flap settings greater than 30 degree due to a downward pitch encountered under certain combinations of airspeed, side-slip angle and center of gravity loadings" Since wing-low drift correction in cross wind landings is normally performed with w minimum flap setting (for better rudder control) this limitation did not apply to that maneuver. The cause of the pitching motion is the translation of a strong wing downwash over the tail in straight flight to a lessened downwash angle over part of the horizontal tail caused by the influence of a relative "upwash increment" from the upturned aileron in slipping flight. Although not stated in the owner's manuals, we privately encouraged flight instructors to explore these effects at high altitude, and to pass this information along to their students. This phenomenon was elusive and sometimes hard to duplicate. but it was thought that the pilot should be aware of its existence, and know how to counteract it if it occurs close to the ground.

When the larger dorsal fin was adopted in the 1972 172L, this side-slip pitch phenomenon was eliminated, but the cautionary placard was retained. In the higher powered C-172P and C-R172 the placard was applicable to mild pitch "pumping" motion resulting from the flap outboard end vortex impingement on the horizontal tail at some combinations of sideslip angle, power and airspeed."

I take Mr. Thompson to be an authority on Cessnas, and highly recommend his books. In once did experience the phenomenon while slipping an older 172 with flaps extended. It was startling, though manageable. In all my flying in newer 172's, I have never encountered it.

[Vilters]

Some forget that the "modern" regs did not exist when most of our aircraft got their type certification in the old and forgotten days.
There are quite a few with a placard "Slips with flaps prohibited".
Anybody trying to sideslip a Jodel with flaps might be in for some nice tumbling if they don't keep the speed high. (They flick around like clockwork if you go too slow.)
Another one is a Morane with flaps and slots out? Oh boy. Better have some altitude and fresh under ware ready. LOL.

[Pilot DAR]

There are quite a few with a placard "Slips with flaps prohibited"

Cessna 172's? I've never seen one in North America with the word "prohibited", it's "avoid". From a regulatory standpoint, there's a big difference in the intent of these words on a limitation placard.

Yes, FAR Part 23.177 is more restrictive than it's older equivalent CAR 3.118 in terms of the requirement for slips with all flap positions. The 172 is certified to CAR 3.118, which is more permissive.

I cannot speak for Jodels and Moranes, I have no experience with those types.

[Maoraigh1]

"Anybody trying to sideslip a Jodel with flaps might be in for some nice tumbling if they don't keep the speed high. (They flick around like clockwork if you go too slow.)"
No experience with flap Jodels, but over 1500 hours on DR1050 with airbrakes. Nothing in the manual, but I'd read reports of a "flick" which is harmless. I've never managed to induce it while trying to do so, but, as pax, with the pilot sidesliping and airbrakes out, suddenly the wings flicked level. The pilot had never heard of this, and was surprised but not concerned.
The suggested cause is airflow blanking by the fuselage with the underwing airbrakes out.
It may depend on AUW and CofG. That was on the annual air test at near max AUW.

[B2N2]

I’m surprised nobody has mentioned the doors open technique, by far the quickest way to get a Cessna to the ground:

- Power idle
-Full flaps
- Hold door open with your left knee or right respective and shove the nose down to max flap speed.

Made that all up by myself and works like a charm.

[Pilot DAR]

- Hold door open with your left knee

If I need to get a plane down quickly, I use my [left] knee differently. I'll apply a load through it to the rudder pedal, and enter a full slip, with full flaps. Aside from the noted "Avoid" placard, this is a maneuver trained in normal handling techniques, and is low workload for the pilot compared to forcing a door. Though, most importantly, if I actually had a fire in the engine compartment, I would not want a cabin door open!

But, as we're talking open door on a Cessna in flight (a non approved procedure); if you're flying all trimmed for straight and level, at a modestly slow speed (so you don't damage the door), and you force open the left door a few inches, which way will the plane turn, and why? I have done this many times, and surprised myself as to which way the plane went, and why.....

[Eddie Dean]

I’m surprised nobody has mentioned the doors open technique, by far the quickest way to get a Cessna to the ground:

- Power idle
-Full flaps
- Hold door open with your left knee or right respective and shove the nose down to max flap speed.

Made that all up by myself and works like a charm.Had door pop open in cruise, and for reason I still don't understand the rear screen blew inwards

[biscuit74]

Another one is a Morane with flaps and slots out? Oh boy. Better have some altitude and fresh under ware ready. LOL.

Aha - the superb 'tin parachute' as the French used to describe the MS406 Rallye. Many happy tugging hours in those. Terrific for steep approaches and needed a good strong pull and ether enough speed for the flare or a good dose of power.
The thing that terrified me was trying to stall the beast with full flap and full power. Of course the slats came out and the attitude was extraordinary, while the ASI effectively stopped reading.. I chickened out and pushed to recover; I wonder what it would have done - flicked, or just mushed horribly? Excellent ailerons so there was still good lateral control when I abandoned the effort.