790390-2 — Fan Air Temperature Sensor Repair & Overhaul

Component Overview

A fan air temperature sensor measures the temperature of fan-discharge or cooling air used as the heat sink in precoolers and air-to-air heat exchangers, feeding signals to the bleed and thermal control logic that modulates cooling-air flow and protects downstream pneumatic and ECS components. As a temperature sensor, it typically houses an RTD or thermocouple element in a probe inserted into the air stream, with its resistance or voltage tracking temperature. Degradation modes include element drift and aging, open or shorted windings, broken or chafed leads and connector corrosion, moisture intrusion, cracked or eroded probe sheaths, and loosened mounting that shifts the measurement point. These produce out-of-tolerance or erratic readings that corrupt temperature control. Repair covers element replacement, lead and connector restoration, and calibration against reference standards.

Aircraft Application

Part number 790390-2 (Fan Air Temperature Sensor) is installed on the Boeing 747. QTC supports operators and MROs servicing this platform with certified repair and overhaul.

Our Repair Capability

QTC repairs and overhauls 790390-2 to the original manufacturer's specifications under our FAA and EASA Part 145 approvals. Our team — including former OEM sensors & switches engineers — performs teardown, inspection, cleaning, component replacement, functional testing, and certification, returning a serviceable unit with the appropriate airworthiness release. We also develop repairs for rejected and beyond-economic-repair (BER) hardware.

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Related Parts

Other fan air temperature sensor part numbers we repair — view all Fan Air Temperature Sensor parts →

Frequently Asked Questions