FUEL QUANTITY PROBES

DC Fuel Probes with Grounded Outer Tube

LMS’ DC Fuel Probe is compatible with a 200v/m EMI environment. The probe utilizes two graphite composite tubes as the capacitive elements. The outer tube is grounded to the airframe which provides a Faraday cage shield around the probe components. This design shields the diodes from the 200v/m EMI levels. The two tubes are structurally joined by a nickel-plated cap or flange, and linked to the system with an EMI connector. The design protects the probe elements from arcing. The weight reduction benefit is especially noticeable when compared with metal two tube and three-tube designs.

Fuel Density Measurement

The LMS DC Fuel Probes are density compensated by measuring temperature and using a proprietary LMS design for correcting the variation of dielectric constant to fuel density.

Aircraft Compatibility

The LMS Grounded Outer Tube DC Probe is presently in production and being delivered for the CH-47F, UH-1 and AH-1 aircraft upgrade programs and EMI testing has been successfully completed.

DC Fuel Probe Features

Robust two composite tube design with EMI compatible outer tube
Won’t dent, scratch or absorb hand oils
Low level capability
Full density compensated probe
No coaxial shielding (over-braid only)
Lowest cabling complexity
No outer tube shorts to ground
More accurate pre-calibrated system
No friction or riveted electrical connections
No fatigue or cracking under high vibration or slosh loads
Half the weight of three-tube aluminum EMI probes