AS-LLE Liquid Level Sensor

Sensor element with single or multipoint sensors
The AS-LLE liquid level element utilizes single or multiple RTDs mounted in thermowells for direct installation into tanks, reservoirs, sumps and gearboxes on commercial and military aircraft, spacecraft, vehicles and marine applications. This sensor is also available as single point and multipoint liquid level and interface elements that connect to FCI or customer provided electronics to indicate presence or absence of liquid level or interface at the sensing point(s).

Please complete and submit the attached Application Data Sheet or contact FCI’s Sales Representative in your area to receive a technical quotation for your Liquid Level and Interface Element application.


  • Remote oil level sensor (ROLS)
  • Fuel level detection
  • Automation of sight gauge level detection
  • Collection sumps
  • Hydraulic and coolant reservoirs
  • Oil/water interface detection


Service: Liquid/gas level and liquid/liquid interfaces. Single RTD (intermittent indication) and dual RTD (continuous indication) monitored applications standard.

Accuracy: ± 0.25 inches [6.35 mm]

Repeatability: ± 0.1 inches [2.54 mm] level elevation.

Time Response: Single RTD intermittent detection sample frequency many be every 2 minutes or longer; dual RTD continuously monitored detection response time is 1 second or greater depending upon switch point setting.

Reliability (MTBF): 100,000 to 250,000+ hours in gearbox service depending on configuration.

Qualifications: MIL STD 810 and RTCA/DO-160, customer project qualification support optionally available.

Quality System Approvals: ISO9001 and AS9000

Weight: 0.05 to 0.2 lbs. [ 0.02 to 0.09 kgs] depending on configuration.

Materials of Construction:
  • Standard: All welded 300 series stainless steel.
  • Optional: Hastelloy C, titanium and other alloys.

Process Connection: Flanged, threaded per AS930, AS4395, MS33656; surface mounted for internal applications; sight gauge retrofit mounting, or other as required by customer.

Insertion Length: Flush mounted to 150 inches [3810 mm] as required by customer.

Operating Temperature: -65° to +400° F [-54° to +204° C], higher temperature service optionally available.

Operating Pressure: To 3000 psig [207 bar(g)]

Proof Pressure: To 6000 psig [414 bar(g)]

Electrical Connection: Military, commercial connector or potted flying lead.

Controller - Provided by customer of FCI

Operating Temperature: -40° to +160° F [-40° to +71° C] Higher temperature service optionally available.

Input Power: 28 Vdc nominal per MIL STD -704.

Power Consumption: 50 to 85 mA.

Output Signal: Source/sink or open connector.

Enclosure: Anodized aluminum and environmentally sealed.

Electrical Connection: Military or commercial connector.

EMI/ Lightning Protection: MIL STD-462 and RTCA/DO-160

Optional Equipment: Process temperature output. LED drivers, controller functions (time delays, etc.)

Weight: 0.8 lbs [ 0.36 kgs]

Optional N.I.S.T. Test Lab Calibration Services Factory N.I.S.T. calibration is available as an option for customer specified setpoint(s).