Dirty dive engine fire drill

[UAV689]

Hi all, quick question, I am doing cpl at present and one of the exercises is engine fire, dirty dive to put it out, forced landing.

when doing a dirty dive we are limited to undercarriage speed and max flap speed, which generally gives quite a steep dive. Once fire is out clean a/c, get yourself sorted into field.

My question to you guys is, why do a dirty dive? Why not a dive clean and dive at a faster speed, but shallower angle, maybe losing less height? I have not tried in a/c but can you dive clean at a faster speed than dirty and lose less height?

There are perhaps other considerations ie getting on deck quick as possible, but it seems like a possible waste of height and time to go through drills and pick suitable field etc. And also from a speedy clean dive you could convert speed to height once fire out giving you more time also.

Any credence in diving clean, or am I being a dunce.

[Genghis the Engineer]

A few obvious reasons for a dirty dive, as opposed to a clean dive.

- It is lower in airspeed, so you won't need to get rid of that airspeed to land.

- It puts the gear down early, before the fire buggers up the hydraulics and/or electrics.

- It does get rid of height quickly, and you'd rather be on the ground on fire, than airborne on fire.


Incidentally, I personally think it's a silly bit of the CPL to a large extent. I don't disagree with it's inclusion, but many of the far more likely emergencies - comms failure, generator failure, control restriction, fumes in the cockpit - get pretty much ignored in favour of the "big two" of engine fire and engine failure which are astoundingly rare by comparison with those.

However it's in the test, learn it and do it that way!

G

[bingofuel]

The part that amazed me is a reluctance to sideslip. Yes, I know some aircraft have limitations sideslipping with flap, or gear, but if the donkey in front of me is ablaze, then a sideslip will at least move the flames to one side and out of my face, and might even keep the smoke out of the way so I can see the field I am about to land in.

Just my tuppence worth

[UAV689]

Thanks genghis,

Excellent points, I was thinking it was those reasons you gave, the only thing that was making me doubt it was at the of the dive I am told to clean a/c then find field and use gear/flap accordingly, but if I put the gear up I may not be able to get it back down again which I have always thought odd!

I agree with the focus on engine fire a bit much, probably better to do a ones you mentioned, maybe even generator failure, leads to smoke in cockpit, leads to electric fire, then motor etc. This multiple failure technique was given to me in the university air squadron many moons ago

[Duchess_Driver]

An interesting debate we were forced into the other day is whether to pitch up to stop the prop before starting the downward trip...

Can't say I'd like to be hanging around getting toasted feet waiting for the windmill to stop but can anyone shed any light on why this may or may not be a good idea?

As Ghengis says, the prime reason for dropping gear and flaps is so that they're down and usable just in case the electrics/hydraulics get fried. Can't say I've ever been recommended to clean up once the fire is out but pitch once more for best glide for the configuration you're left with and sort it out from there.

On the FI course I do focus on all of the emergency drills, I hope evenly. Not something I've got too much time to cover on the CRI course though.

As ever, more than one way to do things - deciding which ones best is always the difficult part.

DD

[mad_jock]

Just do your CPL in a twin and then you don't have to deal with all that pish.

[D SQDRN 97th IOTC]

I always thought the priority was to get onto the ground before you got possible structural failure in a twin.......
If you get to 50ft above the ground with the fire still blazing, are you going to priortise landing or getting the fire out?
If the fire has already knocked out the gear before you could lower it, are you going to try to manually put the gear down - for example let's say the fire was in the LH engine on an Aztec which houses all the hydraulics.....or are you going to put the aircaft onto her belly. Is obvious answer, eh peeps?
So configuration for fastest loss of height is full flap, gear down.i.e. max drag to offset the steep angle of descent.
If you had airbrakes, then these should also be deployed.

[Genghis the Engineer]

As Ghengis says, the prime reason for dropping gear and flaps is so that they're down and usable just in case the electrics/hydraulics get fried. Can't say I've ever been recommended to clean up once the fire is out but pitch once more for best glide for the configuration you're left with and sort it out from there.

On the FI course I do focus on all of the emergency drills, I hope evenly. Not something I've got too much time to cover on the CRI course though.



Odds are however that anybody you're doing a CRI course with has already survived their own share of emergencies, and possibly done a CPL course also. The CRI does ration what you can deliver - I was teaching tailwheel at the weekend, which isn't in the CRI syllabus either (nor in the standard FI course I believe?) Hopefully it does deliver the right pedagogical skillset to take a pilots existing knowledge and deliver that as a teaching package - I'm sure that's what you're trying to achieve?

My CPL instructor used to keep telling me that I had a fire in the right hand engine. Still working out where that was in an Arrow?

G

[mad_jock]

Right clean v dirty. This applys to twins and singles.

My thoughts.

You have an aircraft of suspect structural integrity.

High speed even at flight idle/min power/min throttle what ever your type has the prop will still be driven by the air flow. High speed causes high back pressures in the engine therefore more likely to cause structural failure of the engine.

High rpm drives the fuel pump faster so more fuel to the fire.

High speed more structural loads to the airframe which will be degrading every second and going soft with the heat.

Gear down will absorb some energy, more that gear up.

Low speed elevator less responsive so less likely for you to over control and less load on the airframe.

Again for roll.

Once your services are out, failures of other systems don't make you have more work to do in limited time period. Sky above you is useless as the saying goes.

I was always taught that you have 7 mins with an uncontained engine fire in an in wing engine. Then the spar goes.

I do wonder though about the CPL test singles V twins.

I did IR first then CPL and when I saw all the stuff we would have to do in the Single I thought how much to do it in the twin 450 quid. Ta very much I will stick to banging around at 120 knots on the nav. An engine failure and go-around, bread and butter after the IR. Glide approaches and the other exercises in a single no thanks.

SEP rating on my CPL is exactly the same as someones who did there CPL on a complex single. MInd you I have never flown a complex single and I very much doudt 90% of CPL will ever fly one again after there CPL test. Seems a whole load of pointless training to me.

And all the instructor course seem to focus to much about the nitty gritty of flying. When in my opinion they should focus more about how students learn and how to supply information to the student to learn, and how to set up an enviroment which the student can learn in. The pre course flight should test all the emergencys etc and if the potential FI can't do them or doesn't know them tell them to bugger off until they can.

[BEagle]

If engine fires in single-engined piston aircraft were as common as this somewhat daft CPL trick pony exercise would indicate, then all SEP aircraft would be required to be fitted with engine fire suppression systems.

They aren't, of course, so why is this silly high speed descent nonsense required?

[mad_jock]

Thats my views on it as well BEagle.

I can see the point of it when folk were chucking themselves around the sky in high performance singles shooting at each other but I can't find any accident reports of this training being of any use whats so ever.

[mad_jock]

I have had in my time on SEP

Electrical failures (many)
Instrument failures 3-4
vacum failures to many to remember.

Mind you there isn't much scope for cocking it up when all of them can be solved by looking out the sodding window. Then if your radios don't work phoning the tower up on your mobile.

[Genghis the Engineer]

Agreed.

I have had a few engine failures testing homebuilts, but never in anything with a CofA, and only one in a PtF aeroplane that wasn't under test.

I've had two generator failures in CofA aeroplanes, several comms failures of one sort or another, a DI failure in a CofA aeroplane, a compass failure in a PtF aeroplane, a fuel system that decided to only transfer from one tank in another PtF aeroplane - all of which are contentedly glossed over by most PPL and CPL training in preference for two astoundingly rare occurrences.

We had a carbon fibre propeller spontaneously combuse once on a test programe - shutting down and deadsticking it in was the obvious solution, so we did. But, that's what test programmes are for and I've never heard of such a thing happen on a certified aeroplane.

Just one of those ways where the training system, and reality, just don't line up.

G

[EK4457]

Quick point on the subject of emergency descent.

There is a lot of reference to the ROD being faster with flap out. And I fully understand that drag increases and L/D ratio decreases with flap. However, you are limited by Vfe.

I was taught in both my CPL and MCC course (737) that you simply descend at Vne (or Vmo) whilst clean in order to get the best ROD.

I suppose it could be type specific with the difference between Vfe and Vne being the deciding factor. If there is not much difference then use flap and vice versa?

Any thoughts?

EK

[Reverserbucket]

Surely the flap/gear speed limitation is more a function of the training environment though? In the event of a real fire you could exceed these without worrying too much about the outcome which would likely be less of a concern than not reaching the surface in one piece.

Another advantage of the low speed dive with flap is that hopefully you have a suitable landing site in mind which you are planning the descent towards. At some point a transition will be made from a spiral dive to a stable landing attitude which will be a little more manageable from a glide with flap at lower speed than a Vne spiral.

[Genghis the Engineer]

Well, not many pilots are equipped to know what the margin is between the limiting speeds and actual structural failure, and none are equipped to know how much damage a fire is causing where they can't see it.

Add to that, that the way I normally light the fire in my living room is blowing on the spark....

Add further to that that I will almost certainly want to land at the end of it, so want to be fairly close to approach speed at the end of the dirty dive.

.... and personally I want a combination of high RoD and low speed, so staying below VFE works fine for me.

G

[Big Pistons Forever]

The accident record show engine fires in GA aircraft are very rare. The single highest cause, by a wide margin are fires that are the result of exhaust system failures in turbocharged aircraft which allow hot exhaust gases to vent directly onto an unprotected aluminum structure.

They are also heavily correlated to inadequate maintainance. The good news is in all of the accident reports I have read the fire immediately went out as soon as the engine was shut down and the fuel and ignition turned off, therefore the accident/incident record would indicate that the most important pilot action is early recognition and a prompt shut down followed by a normal forced landing. This was exactly the case for a friend of mine who experienced an EFATO engine fire in a C 421.

While you obviously do not want to dawdle getting to the ground you still have to set up a survivable forced landing, which will obviously be harder if you start trying to transition to the forced approach profile low to the ground doing VNE.:uhoh:

[Pilot DAR]

While you obviously do not want to dawdle getting to the ground you still have to set up a survivable forced landing, which will obviously be harder if you start trying to transition to the forced approach profile low to the ground doing VNE.

My thoughts too. If I had to get down very fast, it would not trouble me to exceed Vfe by 20%, and slip aggressively. I would do it dirty, as the forced landing area I had chosen would very certainly slide under me by a mile pulling out of Vne.

I think there are lot of more more likely emergencies I would train for in a GA aircraft before engine fires. Were my opinion to carry any weight, I'd discuss considerations for and engine fire, and then move on to something more common....

[BigEndBob]

My first instructor asked what should i do to put out an engine fire.
He said he had seen aircraft diving during WWII only to have the wings burnt off, so first course of action try putting fire out by stopping the prop, by slowing to stall so as to stop pumping out fuel and oil.

[goldeneaglepilot]

Having experienced an engine fire on a PA140 during the climbout for a flight test for a star annual, I can vouch that shutting everything down and then trying to stop the prop BEFORE your max rate ROD is an effective way of slowing the flames down. I had been briefed initially by the CAA pilot who signed me off for the test flying, he was an ex military Empire test pilots school pilot and experienced test pilot for various companies before the CAA. His advice was spot on.

Beating hell out of the mechanic who forgot to tighten the fuel line is a great way of stopping it happening again - as is being selective of the companies you do air tests for...

[Madder]

To OP.

Generally I believe in following the described procedure from the aircraft POH/AFM. Its really quite simple in my opinion.

What does it say?