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Author Topic: Strange TQ Indications  (Read 1145 times)

seanmcgillivray

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Strange TQ Indications
« on: July 31, 2022, 11:34:17 pm »
Flew out to OSH last week and had an uneventful trip out. Today departing I was getting what best can be described as a ďroll backĒ on my right engine TQ indicator on the Meggitt.

Indicated as low as 31% with no appreciable dropped in EGT (10 degrees) and no change in FF. I got no adverse ya. This happened several during the flight.

Any suggestions?

Side note and I donít know if is related I had my first every hiccup on the right engine. For about 1-2 seconds I got a drop in TQ and Temp. Then right back to normal.

donv

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Re: Strange TQ Indications
« Reply #1 on: August 01, 2022, 12:00:10 am »
Sounds like a torque sensor to me.

Adam Frisch

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Re: Strange TQ Indications
« Reply #2 on: August 01, 2022, 09:11:15 am »
I had EGT and all that drop off and act erratic on a night departure out of home airport. Got my attention, but didn't sense any adverse yaw. It was as simple as cleaning out the cannon-plug on engine firewall.
Slumming it in the turboprop world - so you don't have to.

seanmcgillivray

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Re: Strange TQ Indications
« Reply #3 on: August 08, 2022, 08:40:04 am »
Update, cleaned the TQ transducer electrical connection. 4 subsequent flights no issue.

seanmcgillivray

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Re: Strange TQ Indications
« Reply #4 on: August 20, 2022, 12:16:17 pm »
Follow up. Could really use some help on this. If anyone has someone I can speak to on troubleshooting I would be thankful.

I have a Meggitt EDU. (would do anything to get this replaced)

So far on flights over an hour and in the flight levels this issue shows itself.

TQ on the right engine will drop from cruise (usually about 57%) and fluctuate between 50 - 30%. EGTs will fall slightly during this abnormal. (5-10 degrees) Yesterday while descending I pulled from 57 to 45 on my left and measured in excess of a 100 degree drop. Fuel Flow stays the same during the abnormal.

What has me scratching my head and not knowing where to start is the correlation between TQ and the drop in the EGT. Unless there is some kind of compensated value in the Meggitt system. Those should be two different readings.

Lastly and it always gets my attention is a "blip" in fuel flow each time this abnormal happens. I will get a momentary drop of 6ish lbs and then right back to normal.

ECA did GBI, HSI, TQ sensor and Fuel Controller about 100 hrs ago.

Anyone that can point me in a direction to start troubleshooting would be appreciated.

(Video and pic links)


https://www.dropbox.com/s/qf4c0uldop37x4q/IMG_0519.HEIC?dl=0

 
« Last Edit: August 20, 2022, 12:18:49 pm by seanmcgillivray »

donv

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Re: Strange TQ Indications
« Reply #5 on: August 20, 2022, 12:20:42 pm »
Is this an indication problem, or is something actually changing with the engine?

seanmcgillivray

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Re: Strange TQ Indications
« Reply #6 on: August 20, 2022, 12:25:30 pm »
Video link:

https://www.dropbox.com/s/1lczi09elcjv3og/IMG_0518.MOV?dl=0

I can't tell Don. The change in the EGT is odd. The blip is odd.

Looking for advice.

donv

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Re: Strange TQ Indications
« Reply #7 on: August 20, 2022, 12:31:42 pm »
Looking at that video, that appears to me to be an indication problem. If the engine were actually fluctuating in power that much, you would definitely feel and hear it-- the yaw alone would be very noticeable.

I had an issue with my airplane where one of the EGTs would jump around. During the hot section, they identified minor damage to the engine wiring harness and replaced it, and the problem has completely gone away. Could be something like that, which would explain both EGT and TQ fluctuations.

seanmcgillivray

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Re: Strange TQ Indications
« Reply #8 on: August 20, 2022, 05:34:56 pm »
Don you got a number of someone I can call at Aero Air so I can bring it up?

Also need my AC serviced.

donv

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Re: Strange TQ Indications
« Reply #9 on: August 20, 2022, 07:58:51 pm »
Call the main number (503-640-3711) and ask for Richard Urban, if you want to schedule something, or Dan Black if you want technical advice.

donv

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Re: Strange TQ Indications
« Reply #10 on: August 21, 2022, 06:41:41 pm »
I will say, intermittent indication problems can be tricky to resolve. Usually they are somewhere in the wiring or connectors.

Bruce Byerly

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Re: Strange TQ Indications
« Reply #11 on: August 23, 2022, 01:21:53 am »
Not sure I would touch it if itís intermittent and at cruise. Only when cold soaked? Clearly indication. Maybe carefully clean some connections and see what happens. Messing with that Meggitt at this point is not worth the risk imho.

donv

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Re: Strange TQ Indications
« Reply #12 on: August 23, 2022, 11:31:35 am »
Bruce, do you think it's the Meggitt itself or do you think it is the inputs into the Meggitt?

Bruce Byerly

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Re: Strange TQ Indications
« Reply #13 on: August 24, 2022, 02:31:40 am »
Bruce, do you think it's the Meggitt itself or do you think it is the inputs into the Meggitt?

I thought I read he cleaned up some connectors and it went away. Also only at altitude? Seems like connections, wiring but if you short out the DAU, youíre screwed.  I would be very careful. It may be annoying but itís probably going to be a year before thereís an alternative like Garmin.  We need to stretch the glide on these boxes. There is zero support unless thereís a mad scientist out there who can fix them.  I donít know anyone and it would have to be an uncertified repair even if it was possible.  Iíd love to know have an option other that putting stock gauges back in or an EI setup on a 337.

seanmcgillivray

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Re: Strange TQ Indications
« Reply #14 on: August 24, 2022, 11:11:37 pm »
Bruce,

Not going to tough the Meggitt. Gonna clean all the other connections.

Is Garmin really a year out? Feel like I was told that last year.