KV-11

KV-11 altitude corrector in the AP-34B system

The KV-11 is an aircraft altitude corrector used in the AP-34B automatic flight control system of Mi-8 and Mi-17 family helicopters. It works in the vertical stabilization channel and provides altitude-related correction signals for the autopilot. The unit is not a cockpit altimeter and is not used by the crew as a primary altitude display. Its function is internal to the automatic control system: it converts altitude changes into electrical signals that help the autopilot hold or correct vertical flight parameters.

Altitude correction role of the KV-11 unit

In flight, altitude can change because of pilot input, vertical air movement, speed changes, power changes or helicopter attitude shifts. The KV-11 gives the autopilot a signal connected with barometric altitude variation. This signal is used in the vertical control channel, where the system compares the aircraft’s actual behavior with the selected stabilization task. The corrector helps reduce unnecessary vertical deviations and supports smoother altitude holding during level flight, climb, descent and transition modes, depending on the operating logic of the AP-34B system.

KV-11 in the vertical stabilization channel

The KV-11 works together with amplifiers, control units and executive elements of the AP-34B autopilot. Its signal is part of the chain that supports altitude stabilization and vertical flight correction. The corrector does not move the controls directly. It provides altitude-dependent information that is processed by the connected autopilot equipment before any control action is formed. If the KV-11 output is incorrect, the fault may appear as poor altitude hold, unstable vertical correction or failure during autopilot channel checks.

Barometric signal conversion in KV-11

The KV-11 converts barometric altitude change into a proportional electrical signal. Inside the system, this signal is used as a correction input rather than as a pilot display value. The unit includes a potentiometric output path, and its accuracy is specified at different altitude points. During testing or adjustment, these values matter because the corrector must keep its output within the required limits across the operating altitude range. A unit that looks serviceable externally may still fail if its potentiometer behavior or tracking accuracy does not meet the required values.

Installation of the KV-11 corrector on Mi-8 / Mi-17 helicopters

The KV-11 is installed within the autopilot equipment area, normally in the avionics or autopilot bay according to helicopter layout. It is used on Mi-8T, Mi-8MT, Mi-8AMT, Mi-8MTV-1, Mi-17 and related variants fitted with the relevant AP-34B configuration. Since Mi-8 family helicopters can differ by equipment set, wiring and modernization status, the corrector should be checked against the aircraft parts catalog and AP-34B documentation before replacement. The designation KV-11 may also be written as KV11 or KB-11 in some documents.

Power supply and service checks for KV-11

The KV-11 operates from both DC and three-phase AC aircraft electrical supplies. Correct voltage, frequency and phase condition are important for stable operation of the vertical channel. During maintenance, technicians usually check the housing, connectors, mounting, wiring, electrical continuity, output behavior and documentation. Since the unit works inside an automatic flight control loop, troubleshooting should include the connected amplifiers and downstream control circuits. A problem in wiring or power supply can look like a failed corrector, and the reverse is also possible.

Supply and documentation for KV-11

The KV-11 is aviation technical equipment and may be supplied new, from storage, repaired, overhauled or serviceable depending on availability. For aircraft installation, the manufacturer passport and operation manual are normally requested. If the unit is ordered as a spare part, the request should specify the required designation, condition, documentation and compatibility with the installed AP-34B autopilot set. Before shipment, it is useful to confirm that the unit is not only physically complete, but also suitable for the required helicopter configuration.

Product Type: Altitude corrector
Designation: KV-11
Alternative Designations: KV11, KV-11, KB-11
Function: Generation of altitude-dependent correction signals for vertical stabilization
Application / Where Used: Automatic flight control systems
System / Installation Area: AP-34B autopilot system, vertical stabilization channel
Compatible Aircraft / Equipment: Mi-8, Mi-8T, Mi-8MT, Mi-8AMT, Mi-8MTV-1, Mi-17 and related variants depending on AP-34B installation
System Role: Barometric altitude correction for altitude hold and vertical flight stabilization
Associated Equipment: AP-34B autopilot, onboard amplifiers and executive control elements
DC Power Supply: 27 ±2.7 V
AC Power Supply: 36 ±2 V, 400 ±8 Hz, three-phase
AC Current Consumption: Not more than 0.3 A per phase
DC Current Consumption: Not more than 0.1 A
Operating Altitude Range: 0 to 20,000 m
Maximum Tracking Rate: Equivalent to approximately 200 m/s
Potentiometer Stroke Range: 160–320 m span at 20,000 m
Potentiometer Accuracy at 1 km: Not more than 20 m
Potentiometer Accuracy at 12 km: Not more than 8 m
Potentiometer Accuracy at 20 km: Not more than 3 m
Mounting: Installed within the autopilot equipment bay
Category: Aviation technical equipment / autopilot altitude correction equipment
Condition: As applicable
Technical Documentation: Manufacturer passport and operation manual

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