Both engines toasted

[sir.pratt]

every turbine pilot should have to rig an fcu before they use it - then they might learn to appreciate how fragile they really are.

in fact, how many turbine drivers actually know 1. where the fcu is, 2 what it does, 3. what does fcu mean?

and not shutting down is not really a problem - that's what the firewall T handle is for.....

[pakeha-boy]

well sir pratt....why dont you do us all a favour and share your wisdom....its been donkeys since I flew a Turbine and your "refresher course" would be of interest...thats of course if you know....its the Fuel Control Unit and it.........................

[deadhead]

Originally Posted by Hugh Jarse

Deadhead,
It's common knowledge, not only for the dash, but for any turbine engine that once you select fuel off that you would never reselect it back to on for any known reason until the engine has stopped.

Hi Hugh
My question specifically excluded "common knowledge/sense", it was purely intended to raise the point that it is likely no-one has been specifically trained not to move the said levers out of said position under said circumstances at all. Relying on "common knowledge" is too big (and in this case, too expensive) a gamble in our job, as I'm sure you understand. There is no substitute for experience, or in its absence, good training.
And that leads me to the next question: using your terminology, what constitutes a "stopped" engine? If it is when all rotating parts have stopped rotating, how do we determine this? By instruments? Some turbines I flew (eg Garrett) had RPM gauges so small you couldn't tell when it hit the zero stop, and in others they lost electrical power late in the shutdown sequence so you didn't know! So you had to assume that after a few minutes had elapsed, you could be assured that, indeed, the engines were "shut down".
So then, assuming the Dash 8 has RPM gauges that still have power throughout the shutdown sequence, how long does it take for the N1 to reach zero? Possibly some minutes, and if that is the case who is trained to understand that the Dash 8 engine takes several minutes before it is "stopped?"
Interesting.

[sir.pratt]

i'll stick to my turboprops - virtually every night i do some rigging. you stick to your computer

[Hugh Jarse]

Gidday Deadhead.

My question specifically excluded "common knowledge/sense", it was purely intended to raise the point that it is likely no-one has been specifically trained not to move the said levers out of said position under said circumstances at all.

It's impossible to offer you an answer without including common sense (as opposed to common knowledge). In my experience over the years I've never observed a trainee or expeienced pilot select the mixture from idle cutoff back into the operating range either unintentionally or intentionally (piston engine). The decision (and intent) is to stop the engine so there is no logical reason why you would want to do it (move it from idle cutoff).

Although the condition levers on the Dash carry out several functions (including fuel shutoff), one could still draw a common thread between its function, and that of the mixture lever on a piston engine (purely speaking in terms of them being the primary control of fuel for startup/shutdown).

It's like turning the key off in your car - Why would you switch it back on once you've decided to turn it off? I know it's being over simplistic, but it's illogical (apologies to Mr. Spock).

I'm aware of a number of incidents involving the inadvertant selection of fuel off and back to start feather. All were as a result of accidently moving the condition lever through the shutoff detent (ie there was never the intention of shutting down the engine - only feathering), then realising the error, and quickly moving it back to start/feather. This typically has occured during an abnormal situation such as an ECU malfunction (PW120). I know of nobody who has ever intentionally selected fuel off, then back on in the Dash.

My opinion is that the design of the detents could be better. As for the training aspect, I think there was paperwork issued stating that in the event of an inadvertant selection to fuel off, the condition lever/s should just be left there.

And that leads me to the next question: using your terminology, what constitutes a "stopped" engine? If it is when all rotating parts have stopped rotating, how do we determine this? By instruments? Some turbines I flew (eg Garrett) had RPM gauges so small you couldn't tell when it hit the zero stop, and in others they lost electrical power late in the shutdown sequence so you didn't know! So you had to assume that after a few minutes had elapsed, you could be assured that, indeed, the engines were "shut down".

Yes, I've got a little time on Garretts, too. Being a fixed shaft engine, generally if I looked out the window and the prop wasn't turning, I assumed the internal rotating components were also not rotating.

The run down time of the PW12x varies, but the NH gauges are reasonably accurate. When I wrote "stopped", I meant NH reads zero (FWIW). Limitations for start are in our engineering manual. The correct handling techniques of the condition levers are taught at type endorsement level in our company.

[deadhead]

We're getting close.

I think the point here was that the guy possibly wasn't specifically trained to confirm the engines were shut down by checking NH was zero. Assuming that he knew and understood not to move the condition levers out of fuel off until the engine had shut down, it seems to me that he thought the engine was in fact shut down. The reason he moved the levers out of fuel off was in an attempt to diagnose a possible rigging issue, something even an idiot wouldn't do if they thought the engine was still running.

So then the question becomes: why did he believe the engine had completed the shutdown sequence? What cues was he trained to use? Do dash 8 pilots monitor the engines until NH reaches zero, and then verbalise this? How long does it take for the NH to reach zero? I'm not advocating this as a method, just wondering what happens. Maybe some other dash drivers might like to comment.

Touche re the good ol' Garrett.

[Hugh Jarse]

I think the point here was that the guy possibly wasn't specifically trained to confirm the engines were shut down by checking NH was zero. Assuming that he knew and understood not to move the condition levers out of fuel off until the engine had shut down, it seems to me that he thought the engine was in fact shut down. The reason he moved the levers out of fuel off was in an attempt to diagnose a possible rigging issue, something even an idiot wouldn't do if they thought the engine was still running.

I think you are treading into engineering territory Deadhead, when you write about checking rigging. That's the domain of the engineer, not the pilot. As a pilot, there is nothing in the Bombardier manuals which require the pilot to carry out engineering tasks. An engineer would carry out the procedure him/herself, rather than asking the pilot to do it. After all, they have a far more intimate knowledge of the donks than us.

Nevertheless, the specific case in question is out of my domain. I don't know whether it was pilots or engineers at the controls, and what the circumstances were behind the events. I just hope no-one gets crucified over what mos likely was an innocent mishap.

There's no requirement with the PW12x to monitor Nh or Np to any specific value as the engine runs down. The reason is that the condition lever remains at fuel off until the next engine start. Unlike the Garrett, where you hold the engine stop buttons in until a certain RPM. (for different reasons)

As for the subject of this thread, I have no idea whether pilots or engineers were at the controls. I just hope nobody gets crucified over what was probably an honest mishap.

[deadhead]

Thanks Hugh. You prompted me to dig a little deeper, so spoke to someone closer to the event than I. He said that the person was a check and training captain who was planning to write up the fact that the condition levers were stiff to operate even with the friction loose. He was simply obtaining information for the engineers rather than attempting to fix it himself, not an unreasonable thing to do.
He also said that the pilot was not stood down, and that no disciplinary action will be taken. That is good news.
He also said that their SOPs have already been amended accordingly, so looks like lesson learned, albeit an expensive one...
And of course the best part is that no-one was hurt, at least not physically!

[Cloud Cutter]

Right, I guess that settles it then. A simple mistake, and lessons learned (for all of us who operate similar engines).

Shal we move on.

[sexy time]

Deadhead,

Thanks for getting the facts and sharing them correctly!

Cheers

[Waka Rider]

Without wanting to point,poke throw stones or sticks. Does Air Nelson let F/O's start and shut down engines. This is to compare and contrast different Sop's. Personally I am a big believer in NHP for the sector starting and shutting down the engines. It brings about very good monitoring of the start and importantly the shutdown by both crew. It also allows the skipper to be in a good monitoring position.

[pakeha-boy]

Waka mate....agree totally ....our procedures (SOP,s) have the F/O start but not shut down.........this gives the capt the ability to hold his coffee......and his cucumber sammy and not deal with the tivialities of starting ...love it....the piggy hunting was beauty....

sir pratt....we have a FADEC....A computer,of sorts,that stops us from frying engines....handy little thing I reckon....no rigging or # 8 wire required

[haughtney1]

Waka.....hmmm an airbooos start?..dontcha press a button and move a lever into a detent? (caught a jumpseat on a company 330 the other day...and took notice for a change )

[Waka Rider]

Haughtney have no idea about our Airbus but this was our procedure with regard to NHP starting and shutting down on the Dash 8-300, ERJ145, RJ 100 and B777. On the B777 its pretty simple with autostart you just have to remember to toggle the switch then put fuel to run. Which yours truely has even forgotten to do. Gives you some idea why I am better off trying to operate modern aircraft. Hoping Boeing create something like those clap on clap off lights. Thats an idea for the 787 aye boys. Pleased to say its a beautiful day in Tauranga 22 degrees sunshine not a cloud in sight.

[sir.pratt]

Originally Posted by pakeha-boy

sir pratt....we have a FADEC....A computer,of sorts,that stops us from frying engines....handy little thing I reckon....no rigging or # 8 wire required

i did know that - that's what i meant (but you knew i knew that...

and it's not #8 wire, but black magic, that makes all those little levers talk to each other in a way that they don't all get tangled up

[pakeha-boy]

Black magic....yeah mate,thats exackery what is.....great minds thinking alike

Waka.....if your down at the "Dolphin" have a couple for me mate

[haughtney1]

PB, I reckon hes on the Maungatapu bridge catchin spratts