Barfield CT12A Digital Cable Tensiometer

The Barfield CT12A is designed to measure and verify the tension in aircraft control cables ranging from 1/16” to 1/4" in diameter. It’s essential for ensuring proper rigging and control system performance in both fixed-wing and rotary aircraft. The unit provides accurate, repeatable measurements without the need for conversion tables, helping technicians achieve consistent cable tension in compliance with aviation standards.

Unlike analog models that require manual interpretation and conversion charts, the CT12A provides direct digital readings of cable tension. It incorporates a load cell sensor and LCD display, improving accuracy and reducing user error. Its Standard and Averaging Modes allow for both single and averaged readings, ensuring precision even when cable variances are present.

Single-cable models are calibrated for a specific cable size, while multi-cable versions handle up to seven standard cable diameters using adjustable risers. The multi-cable model’s versatility makes it ideal for operators working with multiple aircraft types. Both configurations use identical electronics and display features, providing the same level of accuracy and reliability.

Barfield recommends a one-year calibration cycle for the CT12A and its corresponding Verification Bar. Annual calibration ensures the unit remains within specified tolerances for accurate tension measurement. Each new or recertified unit includes a Certificate of Calibration that lists the last calibration date, the due date for the next calibration, and the serial number for traceability purposes.

The Verification Bar allows users to confirm that the CT12A is operating within its specified accuracy range. Each tensiometer is matched to a unique Verification Bar, and they must always be used together for verification. Performing a quick check before use ensures accuracy. If readings fall outside the acceptable tolerance, the unit should be recalibrated or serviced to ensure accurate results.

Yes. Depending on the calibration, the CT12A can display readings in pounds-force (LBS) or newtons (N). The unit’s LED indicator shows the selected measurement standard, and future versions of the CT12A offer automatic conversion between pounds and newtons during calibration.

The CT12A utilizes a 3.7V DC lithium battery, providing up to 28 hours of normal operation and up to 14 hours of continuous use. It recharges in approximately 2.5 hours for a quick charge or four hours for a full charge using the included AC charger. The green charging light turns off when the unit is fully charged. Users should avoid operating the unit while it is charging.

The tensiometer is calibrated for standard, multi-strand, non-jacketed aircraft cables made of carbon steel with zinc or tin coatings per MIL-DTL-83420 Type I, Composition A. It should not be used on plastic-coated or jacketed cables (Type II) unless a custom calibration is performed by Barfield. Using the CT12A on unapproved cable constructions can result in inaccurate readings.

Before use, check that the CT12A has been calibrated within the past year and confirm accuracy with its Verification Bar. If the unit has been dropped or stored improperly, re-verify it before performing measurements. Any deviation beyond the specified tolerance means the tensiometer requires recalibration before further use.

Technicians should ensure the handle is fully closed when performing low-tension readings to avoid incorrect results. The CT12A should not be used on cables attached to tension regulators, as variations in regulator spring rate can affect accuracy. Always follow the aircraft maintenance manual for proper tension adjustment procedures.

Averaging Mode automatically averages three consecutive cable tension readings to minimize the effects of variations in cable diameter or environmental factors. It’s ideal for achieving precise results on long or temperature-sensitive control cables. The display shows progress indicators (“-1-”, “-2-”, and “A.XXX”) for each reading and final average value.

The CT12A should be stored in a cool, dry environment between -4°F to 140°F (-20°C and 60°C). Retain the factory shipping container for long-term storage or reshipment and include a small desiccant bag inside the case to prevent moisture buildup. Inspect the instrument for damage or loose parts after transport before returning it to service.

Barfield does not recommend user-performed maintenance or repair. Any malfunction should be addressed by an approved Barfield repair facility, which uses certified instruments and authorized procedures. Users must contact Barfield’s Product Support Division to obtain a Return Maintenance Authorization (RMA) before shipping the unit for service.

Yes. The CT12A features an ambient temperature function to help compensate for temperature-related tension variations. Technicians can view the temperature in either °C or °F and toggle between units by holding the “Backlight/Cable Select” button immediately after powering on the device.

The CT12A’s rugged ergonomic design and skid-protected base prevent slipping and ensure stability on aircraft surfaces. Its compact size and lightweight construction make it ideal for both hangar and flight-line use. The durable housing and backlit digital display enhance usability in low-light or outdoor environments.

The CT12A is a digital cable tensiometer that delivers a direct tension reading on a 4-character LCD display — no calibration chart lookup, no riser selection, and no manual conversion required. Where a T5 series instrument reads a dial position and requires cross-referencing a calibration card to convert that position to actual pounds of tension, the CT12A calculates and displays the tension value directly. The CT12A also offers Averaging Mode, which automatically averages three consecutive readings — addressing the cable surface variation problem that makes manual multi-reading averaging necessary on mechanical instruments. The CT12A is powered by a rechargeable lithium battery and was co-developed with a major aircraft OEM to meet new OEM measurement specifications.

Averaging Mode causes the CT12A to automatically take three consecutive tension readings and display their average. Cable surface variation on multi-strand aircraft cables causes small differences between readings taken at slightly different positions on the same cable under the same tension — the T5 series service manual specifically recommends taking three to five readings and averaging them manually for best accuracy. The CT12A's Averaging Mode performs that process automatically, removing the human calculation step and producing a more repeatable, more defensible final reading. Standard Mode remains available for single-point readings when fast measurement is the priority.

The Verification Bar is a precision reference component that ships serial-matched to each CT12A unit. Before use, the technician clamps the CT12A onto the Verification Bar and confirms the reading falls within the acceptable tolerance marked on the bar. A reading outside tolerance means the instrument must be sent for recertification before use. The Verification Bar carries the same one-year annual recertification requirement as the CT12A itself — both must be recertified together on the same annual cycle. The bar is matched to a specific CT12A unit and cannot be used interchangeably with other units.

The CT12A is calibrated for standard multi-strand non-jacketed aircraft cables conforming to MIL-DTL-83420 Type I, Composition A — carbon steel with zinc or tin coatings. It is not appropriate for plastic-coated or jacketed cables (MIL-DTL-83420 Type II) without a custom calibration performed by Barfield. Custom calibrations for other cable types are available from Barfield for an additional charge.

Multi-cable models are calibrated for up to seven standard cable sizes from 1/16" through 1/4" and can be configured for measurements across those sizes using the same unit. Single-cable models are factory-calibrated for one specific cable diameter — providing the tightest possible calibration tolerance for that specific application. Both configurations use identical electronics, display features, and measurement modes. Choose single-cable for a dedicated high-precision application on one cable size; choose multi-cable for general use across multiple cable sizes on mixed-fleet aircraft.