VAR-30MK Series 4

VAR-30MK Series 4 vertical speed indicator

The VAR-30MK Series 4 is an aircraft membrane-type vertical speed indicator used to show the rate of climb or descent of an aircraft. It is installed on cockpit instrument panels as part of flight and navigation equipment. The instrument is commonly used on helicopters such as Mi-8, Mi-17, Mi-171 and Ka-32, depending on aircraft configuration. It gives the pilot a direct indication of vertical speed in meters per second, helping control climb, descent, approach and hover-related flight regimes where height changes must be monitored carefully.

Vertical speed measurement on VAR-30MK

The instrument measures vertical speed through changes in atmospheric pressure. When the aircraft climbs or descends, static pressure changes. The sensitive capsule and the instrument case receive this pressure with different timing because one path is restricted through a calibrated capillary. This creates a temporary pressure difference proportional to the rate of altitude change. The capsule deformation is transmitted through a mechanical linkage to the pointer. The result is a simple, fully mechanical indication of climb or descent rate without electronic signal processing.

VAR-30MK connection to static pressure system

The VAR-30MK is connected to the aircraft static pressure system. Correct indication depends not only on the instrument itself, but also on the condition of the static pressure line, fittings and the cleanliness of the capillary path. Leaks, moisture, blockage or incorrect connection can make the pointer slow, unstable or inaccurate. For this reason, troubleshooting should include both the variometer and the aircraft pressure system. A serviceable indicator will not work correctly if the static pressure supply is contaminated or not tight.

Series 4 cockpit scale execution

The Series 4 execution is adapted for cockpit use with red night lighting. The “K” index indicates red-light compatible execution. Digits, scale marks and the pointer are finished with a special white enamel or temporary light compound, depending on production and documentation, so the instrument remains readable under red cockpit illumination. This detail matters when replacing the instrument, because similar VAR-30M / VAR-30MK indicators may differ by scale execution, lighting compatibility, series, markings and maintenance documentation.

Application on Mi-8 / Mi-17 helicopters

On Mi-8, Mi-17 and Mi-171 helicopters, the VAR-30MK Series 4 is used as a basic flight instrument for monitoring vertical movement. It helps the crew control climb and descent rate during takeoff, approach, landing and en-route altitude changes. On helicopters, vertical-speed indication is especially useful because small altitude changes can happen quickly during low-speed flight, hover transitions and descent planning. The instrument is usually mounted on the pilots’ instrument panel in a position suitable for direct reading during flight.

Inspection and maintenance of VAR-30MK

The VAR-30MK is a precision mechanical aircraft instrument. During maintenance, technicians normally check pointer zero position, smoothness of pointer movement, indication error, leak tightness, case condition, glass, scale readability and pressure fittings. The instrument should not show excessive pointer sticking, lag or unstable return to zero. Calibration, sealing and test procedures are performed according to the applicable technical specifications and maintenance manual. For supply, passport, label, series, condition, storage history and verification status should be confirmed before installation.

Product Type: Aircraft vertical speed indicator / variometer
Designation: VAR-30MK Series 4
Function: Indication of aircraft climb and descent rate
Application / Where Used: Flight and navigation instruments of helicopters and aircraft
Compatible Aircraft / Equipment: Mi-8, Mi-17, Mi-171, Ka-32 and other aircraft depending on cockpit and static pressure system configuration
Measurement Principle: Pressure-difference measurement through a membrane / manometric capsule and calibrated capillary
Pressure Source: Aircraft static pressure system
Sensitive Element: Manometric capsule inside the instrument housing
Indication Type: Mechanical pointer indication
Measurement Range: 0 to ±30 m/s
Scale Division: 2 m/s
Scale Numbering: Every 10 m/s
Permissible Error at 20 ±5 °C: Not more than ±1 m/s
Pointer Unevenness: Not more than 0.25 m/s
Pointer Zero Offset at Normal Temperature: Not more than ±0.3 m/s
Leak Tightness: Vacuum drop from 600 mm water column not more than 3 mm water column per minute
Operating Temperature Range: −60 to +50 °C
Dimensions: 86 × 98 × 142 mm
Weight without Mounting Kit: Not more than 0.55 kg
Scale Execution: Red-light compatible cockpit execution, Series 4
Technical Specification: DG2.781.001-1 TU
Maintenance Documentation: DG2.781.001-1 RE and aircraft maintenance documentation as applicable

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Warranty
All products are covered by a standard 6-month warranty.
Extended warranty is available upon request and is agreed individually; it may affect the final product price.