Negative oil pressure
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Joined: Apr 2008
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From: nowhere
Negative oil pressure
Saw it for the first time ever yesterday. On a GE90 right at initial engine start. Only went to -1 psi but was a little surprised that the manufacturer would even take the time to provide such a measurement.
Joined: Aug 2009
Aviation Qualifications: ATPL
Posts: 615
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From: GPS L INVALID
Yup, quite common on the GE90s. Oil pressure as indicated on the EICAS is a differential measurement between the oil pressure after the oil/oil heat exchanger and the air pressure in the bearing sump, never seen anything lower than -1psi, so I would still reckon thats actually 0 delta p within the accuracy of the piezo pressure transducer elements.
