121754-5 — Flexible Shaft Assembly Repair & Overhaul

Component Overview

A flexible shaft assembly transmits rotary torque between an actuator drive and a remote output along a curved or constrained routing path where a rigid shaft cannot fit. Within an actuation system, it links a power drive unit or geared motor to surfaces, valves, or screwjacks, accommodating angular misalignment and structural flexing while maintaining torsional stiffness. The assembly typically comprises a multi-layer helically wound wire core inside a protective conduit, with swaged end fittings keyed to mating drives. Repair drivers include torsional fatigue and wire-strand fracture from cyclic loading, conduit wear, fretting and galling at end fittings, internal lubricant breakdown, corrosion, and backlash or binding that develops as the wound core relaxes, all of which degrade smooth torque transmission and positioning accuracy.

Aircraft Application

Part number 121754-5 (Flexible Shaft Assembly) is installed on the Bombardier CRJ100. QTC supports operators and MROs servicing this platform with certified repair and overhaul.

Our Repair Capability

QTC repairs and overhauls 121754-5 to the original manufacturer's specifications under our FAA and EASA Part 145 approvals. Our team — including former OEM actuation 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.

View Actuators capability →

Related Parts

Other flexible shaft assembly part numbers we repair — view all Flexible Shaft Assembly parts →

Frequently Asked Questions