A couple of points, only introduce fuel when ng is stable, not at 12 or 13% (this is a MINIMUN and is often confused by newbees as the point to introduce fuel) unless this is all you can get. On a quick turnaround watch the itt during start prior to moving the fcl to ground idle, let it motor a bit longer, within starter limits to reduce residule heat. Park into any wind if you know it's aquick turn.
ALWAYS unload the compressor gearbox prior to start, air con etc off as per all pre start checklists. Don't be rushed.

The white smoke may be from a defective flow divider, dump valve.
This will often cause white smoke to appear, usually after shutdown as the fuel which dribbles into the can cooks off.
Possibly it may be jammed to the all nozzle position and causing the hot starts. Remember pratts are in the business of selling engines. not making them last forever. Temprature is your enemy unless you have deep pockets. Consider reducing max climb and cruise temps a bit.

With the -42 don't run it at 460 cruise unless you are prepaired to pay for can repairs on you hot section inspection, 425/430 is much better the tas won't suffer much

Quick updates :

I took the aircraft for a spin yesterday performing 5 circuits and landings and taking the absolute beginning of the runway so i have plenty of room to come back down if necessary.

Pleased to say the engine is performing GREAT and she purrs like a kitten! Nonetheless, am getting the blades looked at today by an engine shop.

I also powered down the aircraft and had a play with dry running the starter to see how long it takes for ITT to come down to 150c which would be a good time to introduce fuel. NG stabilizes at almost 16% whilst dry running without any further increase but ITT continuing to drop to around 150deg from 200-300 when just shut down.


JRBarrett : Yes indeed, i am having the battery deep cycled. Further, i think its time to invest in a good ground power unit myself and have it kept at the hangar for starts. At the very least, this should help the battery with 40% - 50% of the starts.

plhought : After the deep cycle, if i dont see some improvements in the battery, i will have it replaced. Funny though that the POH says 13% minimum to introduce fuel (as does the sim training) hence i was always under the impression that this was sufficient, without having training in other -42 aircraft. Nonetheless i suppose this is where the forum has filled in the gaps with the wealth of information which im thankful for.


Piltdown Man : The more i think of it, the more im sure it was the airconditioning (cabin comfort). I am very certain that was turned on when i attempted to start. Further, the airconditioned turned on coupled with an extremely HOT and high ITT having just powered down couldnt have been helpful and wouldve caused that.

Thanks! I do enjoy her very much and the thought of trading her in for something else is rather difficult.

Is there anything particular about the aircraft i could share with you? On the sytems or flying it? Being deeply passionate about it, it is my joy being able to share about the aircraft.

JammedStab : Thanks for the CB popping out suggestion for future starts. It will become alot to manage though with 1 hand on the fuel lever ready to CUT and 1 hand on the starter motor ready to disengage.

Will have to attempt to start and see how paying attention on one more thing feels whilst monitoring ITT carefully.

Thanks!

porterpat : I am confused by the numbers you are quoting but just so i can clarify and absorb the advice for good use :-

I currently like to climb fast and hard to my assigned level as fast as possible, usually FL260 - FL280.

I usually climb at 1,000 - 1,100 fpm and torque setting at 1,250 lbs - 1,270 lbs.

ITT will rise thru the 600's into 740's - 750's at which point i will reduce torque and rate of climb to accomodate ITT and keep ITT below 740's.

Once i reach cruise, i will set torque at 800 lbs - 990 lbs (usually below 1,000) which is "intermediate cruise" setting in the Meridian POH.

At FL260-FL280 ISA+20deg, ITT is around 650 deg - 675 deg and it will stay stable at this temperature until descending at which point it will cool down alot.

Can i clarify what you mean by 460 cruise or 425/430 because 500lbs of torque is minimum to keep it going forward according to the POH and ive not seen ITT temp of 450 in cruise yet but it would make cruising painfully slow it ITT temp was at 450.

I think maybe 500-600 lbs of torque? Being absolute minimum to keep the plane going forward.

I will give it a try on my next flight into the levels and post back with feedback.

Thanks

Not a lot to manage at all. Your hands are where you said they would be(starter and fuel lever) and if you happen to hear an unknown sound during the start that could be a CB, move the fuel lever off.

with 6000 hours on the KingAir 90, 200 and 1900, I have had white smoke as well, no light up, left engine B200. The left engine igniter plugs had packed up. No tick tick tick spark during spool and then white smoke. Being stuck in the middle of Somalia, I swapped an igniter from the right engine across to replace left engine igniter, and started both again and flew back to base. After a short ground time turn around, allow a longer spool time to decrease ITT before entering the fuel and not just at the first opportunity of 14,5%. Also use a NICAD battery as opposed to lead acid. One is expensive I know, but the other certainly does give higher starter spools.

Yes but the POH and sim probably assume starting a cold engine, not an engine that already has a residual temperature of 200+ degrees in the hot section.

Jetjock330: Wow, lucky that swap of plugs got you out of Somalia. Interesting environment to be stuck in.

Thanks for the suggestion. Will definitely ask the maintenance guys and see if we can get something going.


Chimbu warrior : Yes indeed. I think i might even resort to standing outside and spinning the props by hand for 15-20 minutes if i can. I dont mind the exercise and would love to keep my engine nice and happy.

I'm not sure spinning the prop on a free turbine engine will do anything for you as the power section is not turning. As someone mentioned earlier, cranking for a longer period of time prior to adding fuel can cool down the temp if it is still warm although if using battery only, you are depleting the battery. Based on a totally different engine I am operating these days, prior to lightoff, the measured temperature definitely decreases during the initial cranking for a warm engine and increases a bit on a cool engine.

Wind-up alert!!! Best of luck trying to Armstrong a gas turbine!

This thread is now descending into farce -it's been suss for a while, this is now ridiculous.

I'm not sure if I was taken for a ride when someone suggested that to me, bearing in mind that I shared my story with whomever will listen to give myself some reassurance the engine is okay.

It could have been said in sarcasm but I took it in seriousness. Although I will point you to this fact :-

In an attempt to dry crank and "test" to see how the temperatures react and recreate my mess-up, after a few circuits and landings, I taxied and began shutting down the aircraft.

ITT was stable at 620 deg - 630 deg at this point and I cut off the fuel and engine stopped. ITT dropped to around 300 and progressively but slowly declining.

I then proceeded to dry crank the engine and observed ITT drop from 260 deg to 150 deg which I think would be a good time to introduce the fuel.

I released the starter. Of course the prop was still moving but slowing down and the point when it totally stopped, the ITT rises abit again, assuming as the prop is no longer spinning.

The point I'm getting at is this :- I had already released the starter and whilst the prop was slowing down for the next 10-15 seconds, it was keeping the engine cooler as the ITT rose up the moment the propeller stopped totally.

I'm not to proficient or knowledgeable on turbine engines at all but would giving the propeller some movement by hand have the same effect?

Much thanks for all the feedback and knowledge in the thread everyone! Has provided me with a lot of reassurance and comfort and I hope other Meridian pilots may rely on it in the future.

In all seriousness, if that is true, please get some decent training before operating your aeroplane again. They are very reliable when operated correctly but can be trashed in seconds if you do not know how to look after them.

Yes, but only by a few degrees. As JS stated, you will only be turning over the free turbine. It will move some air, but not enough. Your starter is the best option. And taking your last point, on shutdown the ITT will be cooled by passing air. As soon as the air stops, the residual heat in the engine dissipates into the surrounding air causing an ITT rise.

Although my engines are different, when starting a hot engine fuel is not introduced until the N2 is 20% AND ITT is 120 C or less.

Yes, an important point on any free-turbine engine (PT6A, PW100 series, CT7/T700, T58 etc.) Turning the output shaft via the prop has no measurable effect of airflow through the core, because there's no mechanical connection. If the aircraft is parked into the wind, that's a little help, but the starter is the only thing that can make a real difference.

hello ! white smoke occours when fuel is injected into a still hot chamber but ignition is forgotten or the igniters failed . first it evaporated only in the hot chamber without burning then excessive fuel finally self ignited against the hot chamber or you turned ignition on after introducing fuel via condition lever making it ignite . the excessive fuel suddenly igniting resulted in the high itt .

you most probably forgot to turn on ignition on first start attempt .

good news : your engine is fine , 1000 deg for a short time is a non event.

generally on quick turnarounds motoring for 10-15 sec before pushing the condition lever helps much lowering peak start temperatures.

best regards

Speaking about getting a higher rpm on a free turbine engine prior to introducing fuel, I was told once that if you left the propeller tied in place during the start(we used to tie them down on the Twin Otter to keep them from rotating in a strong wind while shut down), you could get an extra 1 or 2% rpm. Never tried it of course, has anybody else.

I know this sounds ridiculous as a procedure, but keep in mind that this is for remote arctic and antarctic ops where what has become a weak battery may only allow one attempt and then you are stuck on the cold tundra or ocean ice along way from anywhere. Then you release or cut the rope after start.

Sounds iffy. Then again, a lot of things they do in the frozen North sound iffy.

These numbers are temps NOT torque.
How can you fly this a/c with so little knowledge?


Can i clarify what you mean by 460 cruise or 425/430 because 500lbs of torque is minimum to keep it going forward according to the POH and ive not seen ITT temp of 450 in cruise yet but it would make cruising painfully slow it ITT temp was at 450.

porterprat ... the -42a pt6 has an itt redline of 800deg with everyday cruise settings of 740 or similar .

your recommendation of cruising in the 425/430 deg itt range instead of 460 is such massive of the shelf that he just asked you what you mean at all with this numbers - an idling pt6 has way more than 460 deg itt ;-)))

there are few pt6 installations where the readout is egt (t5) not itt with your numbers becoming realistic then , but in most installations including the -42a and itt readout recommending 425deg for cruise is plain funny
.

nervermind but you should cancel your comment about knowledge .

best regards

The reason to hold the props is in cold environment, you will damage the gearbox, and or blow prop seals when they come out of feather. The standard arctic first flight is f/o holds the rhs, startup run until oil temp comes up, battery charges, run over to lhs, does the next start, crawls in through back.

Though the preferred method is to run a janitrol through an exhaust stack, not always available