PT-6 chip light

[Lopaka]

We had just dropped off passengers in Treasure Cay, Bahamas and now were on our way to Ft. Pierce when we got the L chip det light. We monitored the guages nothing abnormal, everything constant and in the green when 10 min later the light flickered and went out. 15 sec. after that the torque needle dropped, and there went the engine. We were about 50 NM off shore but made it to Ft. Pierce just fine. The plane was towed to the turbine shop on the field where they pulled the chip detect plug and metal poured out of the engine. We're in the process of getting a loaner installed. Interesting thing (I guess) is, it's a '92 King Air 200 with the original engines. 2,620 hrs tt. Phase I-IV completed 200 hrs ago. I didn't think this was supposed to happen that often, but our sim instructor at FS said he's had twice. You think P&W will be interested in this case being original engines and almost 400 hrs from TBO? Worst part is we had to drive home, but now we've got a couple days off finally so we can fire up the barbi. That's pretty good, my first post and I already slipped in the BBQ thing.

 

[banned username 2]

but now we've got a couple days off finally so we can fire up the barbi. That's pretty good, my first post and I already slipped in the BBQ thing.

Good Man!

Welcome!

Glad to hear everything turned out safely!

 

[capt_zman]

Correct me if I am wrong, but isn't the Chip Light a mandatory shutdown according to the checklist?

Again, may be wrong, but you might not want to tell Pratt that story.

Anyway, glad your safe. Makes you pucker, especially over water.

 

[flywithruss]

Yes, a chip detector is an immediate shutdown. The minute it comes on it is a good sign that your engine is eating itself for lunch. Shut it down now, ask questions later.

Glad you got your machine on the ground safely and nobody was hurt. That's always the #1 priority of course.

Fly safe, y'all ...

R

P.S.: Gotta get a little BBQ note in there ... pass the Texas brisket and the Memphis ribs and I'll have a nice day. Yum ...

 

[FlyingStarr]

Don't Ask Flight Safety that question!

According to Flight Safety the Chip detect is now a shutdown item however, this has not been the case for a long period of time. If you sit through the 200 ground school the instructor will tell you that you should watch the oil temp and pressure and if any changes occur shut the engine down immediately otherwise you could "probably" continue to your destination with no adverse effects.

I've been to two different FSI locations and they both have taught the same thing.

 

[shootr]

I don't have a lot of King Air time but I do have lots of T-34C time. A chip light means the engine will eat itself and SOON! I've never heard of a chip light in a PT-6 that was not real and wouldn't take one lightly. In T-34's, we get the plane down, now. P-3's with a different engine, false chip lights all the time.

shootr

 

[metrodriver]

On the metro: monitor engine, shut down if necessary.

Years ago a Saab 340 crashed after an oil pressure warning light wire had chafed through, crew didn't monitor the other gauges to confirm and shut down the engine while over a substantial stretch of water and crashed the airplane on landing.
I tend to like the monitor thing a little more than shutting down something that is working fine (for the moment).

The T34 and the Caravan have the same problem: it's single engine. You get a chiplight and land asap. You don't want to take chanche here for obvious reasons.

 

[cvsfly]

It depends. Look at the AFM and the annuciator panel. On earlier model KAs the chip detect is a Warning (red) light and most later models (a 1996 B200 in my experience) it is a Caution (yellow) light. I don't recall if Beech actaully made any major changes to the chip sensing equipment or placement to justify the change in the annunciation - maybe it was the lawyers. You as PIC have to evaluate the situation and decide when and where to shut down. Sure you may consider the expense to the engine with an early shutdown or shutdown after the engine is toast. Will you shut it down with a chip light at V1/Vr on a short strip?

 

[ultrarunner]

Just for comparisons sake, here is some stuff off my reference shelf...

King Air F90

red light
Emer procudure
Emer Engine shutdown

there is a note "confirmation should be made if possible prior to eng. shutdown.

King Air E90

Same as F, except the words "if possible" do not appear in the note.

King Air C90A LJ 1063 through 1137

Same as E90

From my memory, flying a C90, LJ 800 or so, the chip light was yellow. Can't locate that checklist right now, but someone will chime in.

As I recall, there was a philosophical decision somewere that changed the lights from yellow to red....however if I were a betting man, i'd say the change was motivated by litigation, than anything else.

And no, there are no differences in the location of the chip detector between red light planes or yellow light planes.

Sorta like that gear handle thing )

Good ole Beech, want's us on our toes!!!!

 

[CRJ700 FO]

Flew several 200's years ago in scheduled service. A crew had the chip light come on and the checklist called for precautionary shutdown. Maintainence tore the engine down and found no metal. The next day the same thing happened and no metal was found. Two days later the chip light came on so before the crew shut down the engine they called the company first on the radio. They said not the shut the engine down as it was probably a faulty sensor. Several minutes later there was a catastrophic failure. When the covers were taken off it looked as if someone had shot the holes in the hotsection. The plane landed with no problems.
If your checklist says shut it down, then shut it down.

 

[501261]

Been a while since I've been in a King Air and consequently I've given away most of my manuals and checklists.

From the Flightsafety C90 Checklist dated January 1998 page A-13:

"Illumination of a CHIP DETECT Annunciator indicates possible metal contamination in the engine oil supply. ILLUMINATION OF A CHIP DETECT IS NOT IN ITSELF CAUSE FOR AN ENGINE TO BE SHUTDOWN. Engine parameters should be monitored for abnormal indications. If parameters are abnormal, a precautionary shut down may be made at pilot's discretion. After illumination of a Chip Detect Annunciator, cause of the malfucntion should be determined and corrected prior to the next flight.”

This was also the way I was trained in the 200 and 350 that the Chip Detect Annunciator was in itself not a reason to shut down. Primarily because it was either a false warning or the engine was already so damaged that shutting it down was not going to help or harm anything any way so that you may as well keep it running (oil pressure change was different since that might cause a line to blow increasing the fire hazard) . Of course the last time I went to King Air recurrent was in 1997 and things may have changed since then.

 

[NGT]

I have a good amount of time in the 200 and have seen the chip light a couple of times and have never shut down the engine based on FSI's newer checklist that calls it a precautionary item. Since it is in the reduction gearing and independant of the engine and stationary if the prop is feathered, over water or at a time when you may need a second engine/generator/ A/C compressor ect.ect.ect you may want to monitor the engine at idle with the prop feathered and available immediately if needed. If the engine indications are normal consider your options before you cage 50% of your power and 70+% of your performance. The chip detection system has never changed only the checklist has. If the prop is stopped and the engine is running you have an available engine and a chip light in a stopped prop. If you have a stopped engine and a stopped prop you have nothing but a chip light. I have landed the 200 with the engine stopped once and with the prop feathered a couple of times(chip light/ bad prop governor/ vibrating blade), I preffer the latter. Just something to consider.

 

[h25b]

My best advice is do whatever the checklist tells you to do, I had a good friend who didn't follow the checklist in that type of situation and had a LOT of explaining to do with the FAA later. Deviating from the checklists brings you in to uncharted waters REALLY quickly and if it doesn't turn out well you've got nothing to turn to when explaining later...

Of course there are some obvious exceptions to this.

 

[skyking1976]

A lot of guys are talking about shutting down engines in response to chip detector lights. How do you know that the chip dectector is not faulty? How do you know there are really particles in the oil large enough to do damage? On our King Air 350 we had an issue with the chip detector light illuminating. This occurred several times with one precautionary landing at an airport other than our destination. After each occurrence the oil sumps/filters were examined and the only metal found was smaller than a grain of sand.

What happened was sometime between QC inspection of the motor at P&W and the chip light occurence, metal fibers had shown up in the oil. It just so happened that enough of the fibers collected on the chip detector magnets to illuminate the warning light. Enough to do damage? No. Enough to warrant an engine shutdown? No again. I once had a mechanic tell me that you have to see serial numbers on an oil chip for it to be large enough to do damage.

The POH for the BE-350 says for a chip light: Montior engine gauges; if abnormal indications are observed, consider precautionary engine shutdown. I believe that Beech is in the process of revising all the past King Air series manuals to reflect this. No sense in turning a cause for concern into an actual emergency situation.

Fly safe and smart,
Skyking

 

[Lopaka]

Update

That's all good stuff. At FSI we practiced both ways, precautionary shut down, and also electing to keep it going and monitoring parameters. It just depends. In anycase, the engine got torn down this morning and they found it to be a 1st stage sun gear failure. They now supposedly have a heavier duty gear to upgrade to. Dallas Air is doing the work. Looks like they may total the engine, but we've got a rep overseeing the process. Big $$'s.