View Full Version : Engine chip light question.
Extol
28th Jul 2017, 17:31
Hello, I had an engine chip light that flickered when I was spooling up the other day in an astar350. It went out and maintenance checked the plugs and said they found carbon on it.The next day the light came on steady after shutdown. I checked and cleaned the plugs myself and found nothing and the light was distinguished. The mechanic said it is ok to fly. They recently changed the transmission, but this is an engine chip light... any thoughts?
hueyracer
28th Jul 2017, 19:58
Have you checked the cables?
Most of the times, this is where the problem is...
The sensors are good, but the cables are usually out in the weather all of the time, and have been installed from day one...
Extol
28th Jul 2017, 22:53
The maintenance was sure that the carbon build up was causing the light to illuminate not the cables. What causes carbon to build up and stick to the chip plug magnets? Is this something to be concerned about if it keeps happening?
riff_raff
29th Jul 2017, 09:04
Unusual that enough carbon debris would accumulate at the magnetic chip detector sensing gap to produce an indication. The only source of carbon debris produced in a turboshaft engine would be the carbon element of any shaft face seals. If a carbon shaft face seal is generating the amount of debris described, it likely has serious problems that require immediate replacement. Check for oil leaks around any locations on the engine where a carbon face seal is used.
I was once told that if you couldn't read a part number on the particle it was okay to fly, mind you, that was said by a mechanic who was not coming flying with us and I'd do what he did and stay on the ground until I knew why this was happening.
hueyracer
30th Jul 2017, 10:51
It should be fairly simple:
Light comes on while you´re at home:
Shut down, let engineering sort it out.
Light comes on while you´re away:
Pull the plug, check for particles.
If there are any: Take a good picture, and use some white tissue to save the chip to take it home with you.
Run up the aircraft again for a ground run (min.5-10 minutes).
light comes on again:
That´s it, you´re staying there...
Light stays off:
Continue flying.
Especially after an oil change or a change of components it is possible to get the light-that is what the engineering section is there for.
Oil samples can be sent in to be analyzed, and the lab can figure out where the particles are coming from....
It should be fairly simple:
Light comes on while you´re at home:
Shut down, let engineering sort it out.
Light comes on while you´re away:
Pull the plug, check for particles.
If there are any: Take a good picture, and use some white tissue to save the chip to take it home with you.
Run up the aircraft again for a ground run (min.5-10 minutes).
light comes on again:
That´s it, you´re staying there...
Light stays off:
Continue flying.
NO, NO, NO and NO!
In the event of a chip light you will inform your maintenance provider before further flight. Pilots are NOT qualified to make an assessment.
You may have NO knowledge of the previous history of chip lights to date.
i.e. with an RR Allison as compared to a Pratt the regime is completely different. On a Pratt you will not see a 3rd chip light indication before it comes apart!
The only source of carbon debris produced in a turboshaft engine would be the carbon element of any shaft face seals.
Unless he is referring to "coke" which is pretty common in RR Allison engines and the Safran Arriel which we assume is in the 350 model in question. Rear bearing "low flow" which is normally associated with how you operate the thing - long ground idle periods - then shutdown soon after. People with RR Allison habits transferring them to the Safran engine is usually the problem. Don't let a Safran Arriel idle for more than 30 seconds. The rear end actually gets hotter and the oil flow is low resulting in "coking". Fix requires removal and cleaning.
Scattercat
31st Jul 2017, 06:32
NO, NO, NO and NO!
In the event of a chip light you will inform your maintenance provider before further flight. Pilots are NOT qualified to make an assessment
Not necessarily so. At several places I have worked, pilots were formally qualified and approved for minor maintenance actions including the removal, inspection, cleaning & replacement of chip plugs. Of course, this was most often done in the field in consultation with the maintenance provider.
hueyracer
31st Jul 2017, 06:32
1. Not every aircraft has a "fuzz burner"...
2. In most part of the world, pilots operating out of remote areas have maintenance training-and are trained and qualified to pull chips......
Shows that plenty of pilots have no idea about remote area work...
ShyTorque
31st Jul 2017, 06:44
Alternatively, fly with Italian electrics and you learn to expect a chip light of some sort every time it rains.
Scattercat,
You can be qualified to remove the plug, clean it and replace it.
What happens to be on it and subsequent action is NOT for the pilot to decide who must defer to the maintenance provider. Otherwise what is the point?
albatross
31st Jul 2017, 18:24
We used to put the chips on "Scotch Tape" and put them in the log book.
We had the 250 course and were qualified to check chip plugs and change oil and filters...sometimes the nearest engineer was 500 -700 miles away.
We did a lot of phone calls or talking on the HF Radio.
In those daze if you landed someplace where there was another helicopter, even if it was not from your company the engineers would offer good advice.
In any case we had the phone number of the 250 tech rep to call if need be.
Olden daze but it worked then ...now not so much.
bluesafari
31st Jul 2017, 20:56
The procedure for action after a 'chip light on' is in the engine MM, in the case of the Arriel 1D, I believe, it is in chapter 72-80-01, it is possible you may need to replace the associated packing before refitting the the detector. It is also possible that the filter may need to be inspected and replaced. A log book entry with a release is normally required. Some engines do not have self sealing mountings for the detectors and consequently there may be a spillage in which case a level check will need to be carried out.
I am aware that on remote operations that crews may be authorised to carry out certain maintenance procedures by the company quality department, please always err on the side of caution.
Stay safe
Alternatively, fly with Italian electrics and you learn to expect a chip light of some sort every time it rains.
@ShyTorque Not that I'm a fan of helicopters built in Italy, but that happens on our U.S. built helicopter as well everytime you hit a shower.
Thomas coupling
1st Aug 2017, 11:40
Put some tape over it.
Put some tape over it.
Funny you should mention that - I have actually seen that happen - pilot was irritated by it - especially in the dark. :confused:
ericferret
2nd Aug 2017, 15:40
Alternatively
Me, What are you doing?
Local eng, Cleaning the chip plug.
Me, Why?
Local eng, If we don't clean it every day the warning light comes on.
Me, Oh Sh*t.
Day one on a new job in Africa.
Also noting that one or two electrical systems were not working as expected an investigation lead to a couple of blown fuses and several wrapped in wire. Apparently damage due to an uncontrolled runaway of a GPU.
It did get better, honest!!!!
helicopterray
6th Aug 2017, 22:39
There are two wired chip plugs on the AS350 if you're flying the Arriel version. One on the pressure side, one on the scavenge.
There are also two chip plugs on the gearboxes, one on the MO1, one on the MO2.
Check all 4 plugs to narrow down the source of the light. Carbon on the plug will not illuminate the chip light, only metallic pieces.
Run a piece of clear scotch tape on the plugs to extract whatever material is on the plugs in order to examine them.