CFM56-7B T25 probe question
Thread Starter
Joined: Mar 2007
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From: Asia
CFM56-7B T25 probe question
chaps,
there has been a number issues of the CFM56-7B having throttle roll backs due to erroneous signals to FADEC due to icing of the T25 probes. I had this discussion with another chap who said that the probe wasn't heated i.e. there is no heating element. It was my understanding that there is and there is a corresponding circuit breaker to match. does anyone have a schematic to show the probe is heated. I do not recall it was heated by engine bleed.
look forward to the responses from the brains trusts!
there has been a number issues of the CFM56-7B having throttle roll backs due to erroneous signals to FADEC due to icing of the T25 probes. I had this discussion with another chap who said that the probe wasn't heated i.e. there is no heating element. It was my understanding that there is and there is a corresponding circuit breaker to match. does anyone have a schematic to show the probe is heated. I do not recall it was heated by engine bleed.
look forward to the responses from the brains trusts!
Joined: Feb 2002
Aviation Qualifications: AME
Posts: 4,183
Likes: 1,119
From: UK
As it's a combined temp/pressure sensor surely heating it would be a problem
here's the URL link.
https://www.slideshare.net/mobile/cc...fm56-7-fueloil
here's the URL link.
https://www.slideshare.net/mobile/cc...fm56-7-fueloil
Joined: Mar 2009
Posts: 60
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From: Prague
Just checked possible ∆T trough LP section and I am really surprised how low is on idle N1. Table is from 56-3, which is bit different, but with same number of stages. PT25 is used for fuel metering and HPTACC schedule. Presure sensing at this station is optional, for engine trend monitoring only. The temperature for both channels is sensed by heated platinium wires with no extra anti-ice.
Last edited by LEVEL600; 7th June 2016 at 12:37.
