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TIT indication & the TD system


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Hey guys

 

My topic is a follow on of this discussion. Over the last several months we have had a large number of TD related

problems. Some have been fixed by the usual TD am or valve change, or just a careful yellow box. Many have either 

been sent to me in the test cell, or I have spotted enough of a disparity to warrent further investigation.

 

The most common failing is a high take off TIT in AUTO, with a lean fuel control. I like to set SLOPE and NORMAL

at 1075°C and take things from there. As long as TIT doesnt exceed 1083°C we're good to go. Normally a new amp

or a bit of careful tweeking of the NULL orifice and the CIT can bring everything in line. Recently these things just

had no effect.

 

Chatting to a test cell operator in the US, he told me that he had installed another TIT guage in his cab connected

to the AMP terminals on the T-block. I did the same and damn near had heart failure - with 1080°C showing on

the IND side, I was only getting 1060 or so on the AMP side. Changed thermocouples and harnesses - voila! problem

solved. I have now made this a fixed check on all engine runs when we do the TD system checks.

 

Referance for this check can be found in 2J-T56-56 SWP 058 03 Sect 15

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On 11/11/2015 at 6:28 PM, pjvr99 said:

Hey guys

 

My topic is a follow on of this discussion. Over the last several months we have had a large number of TD related

problems. Some have been fixed by the usual TD am or valve change, or just a careful yellow box. Many have either 

been sent to me in the test cell, or I have spotted enough of a disparity to warrent further investigation.

 

The most common failing is a high take off TIT in AUTO, with a lean fuel control. I like to set SLOPE and NORMAL

at 1075°C and take things from there. As long as TIT doesnt exceed 1083°C we're good to go. Normally a new amp

or a bit of careful tweeking of the NULL orifice and the CIT can bring everything in line. Recently these things just

had no effect.

 

Chatting to a test cell operator in the US, he told me that he had installed another TIT guage in his cab connected

to the AMP terminals on the T-block. I did the same and damn near had heart failure - with 1080°C showing on

the IND side, I was only getting 1060 or so on the AMP side. Changed thermocouples and harnesses - voila! problem

solved. I have now made this a fixed check on all engine runs when we do the TD system checks.

 

Referance for this check can be found in 2J-T56-56 SWP 058 03 Sect 15

Pjvr , TD tester is very useful for troubleshooting TD system problem and help to identify unservicable components of TD system.

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