Production of gearboxes for turboprop engines

Production of aircraft gearboxes in Česká zbrojovka launched in the seventies of the last century. We have been specializing in production for more than 45 years speed reducers (propeller gearboxes - PGB) and accessory gearboxes (AGB). As the specification of these gearboxes already implies, they are precisely manufactured and assembled in small batches and in compliance with the highest requirements for quality. An integral part of this production is also provision of overhauls.

Both gearboxes, the propeller and accessory gearbox, were part of the M601 engine, used as the drive unit of the popular Czech aircraft L-410 Turbolet. The gearboxes went through gradual modernization and became the base also for the modernized engine H-80.

Speed reducers 

Most of the components required for the assembly of the entire reducer come from our own production. The remaining parts are purchased from certified suppliers. After that, we perform the whole assembly of the reducers. During the assembly process, the product undergoes continuous inspections and tests in accordance with aviation standards.


Gearboxes are produced with the use of precise CNC 5-axis milling of functional holes and surfaces of castings. The most common materials used in the production of gearboxes mainly include aluminium and magnesium alloys. Through proprietary technology, we also produce all gears and shafts. Since CZ-AUTO is part of a strong engineering company, we have capacities to provide heat and surface treatment.

Accessory gearboxes 

The production process of gearboxes intended for propulsion of turboprop engine aggregates is the same as in the case of production of speed reducers. Also in this case we manufacture key components using our own technology and purchase the remaining necessary certified parts from verified suppliers.


Quality management system

Our key competitive advantage is a highly-developed and rigorously applied system of quality control of manufactured parts, including subsequent assembly. For each activity involved in production and assembly, we have corresponding measurement and monitoring equipment. These devices ensure high quality that meets the requirements for supplies to the aviation industry. Monitoring of individual processes and maintenance of measurement equipment is carried out in accordance with directive procedures in the quality manual (QM), which is elaborated in accordance with the requirements of ISO 9001 and aviation regulations.

As part of standard procedures established for accuracy checks, evaluation of shapes, roundness and machining, we perform the following measuring and inspection tests:

Types of measuring tests:

a) Complete measurement of gearing using DO-3 PC and SP60 CNC
b) Measurement of roundness and cylindricity using Talyrond 3
c) Roughness and profile measurement using Mahr Perthometer PCV
d) 3D dimensional and positional measurement using Dea Global and Dea Iota

Types of inspection tests
a) Non-destructive testing of materials using the Tiede Universal 600WE crack detector

b) Evaluation of burnt areas after grinding with the use of Rollscan 300 c) Penetrant testing of surface defects of materials

3 more reasons for aircraft components from CZ-AUTO


Our main activity is production of required components. Due to our experience and sophisticated system of inspections and tests, we are also able to perform necessary assembly. In addition, our customer service then provides our clients with overhauls.


As subsequent customer service, we provide overhauls of reducers and gearboxes. In the initial phase, we perform disassembly and complete cleaning of the entire equipment. On the basis of aviation standards, we analyse and test individual components, whether they comply with the specified values. After we evaluate the parameters of the parts, we propose comprehensive solutions for the realization of an overhaul.


Our company is certified according to European standards and works closely with the Civil Aviation Authority in terms of supplies to the aviation industry. We are authorized by the Civil Aviation Authority for the production and repair of aviation equipment. In addition, we are a member of the Confederation of the Czech Aviation Industry.