DA-30P

Vertical-speed measurement through static pressure

The DA-30P variometer is connected to the static-pressure system. Static pressure enters both the sensitive manometric element and the instrument housing, while calibrated capillary passages delay pressure equalisation. During level flight the pressures balance and the vertical-speed pointer remains at zero. During a climb or descent, the temporary pressure difference moves the pointer in the corresponding direction.

The indicated vertical-speed range is up to 30 m/s for both climb and descent. Passport data specifies operation at altitudes up to 12,000 m and a static-system leakage limit of 4 mmHg per minute when tightness is checked at an equivalent altitude of 3,000–4,000 m. Correct indications therefore depend on the condition of the static line, the rear pressure connection, the calibrated restriction and the instrument mechanism.

Turn and slip information on DA-30P

The turn section uses an electrically driven gyroscopic mechanism. Its scale is calibrated for representative bank angles of 15°, 30° and 45° at a flight speed of 400 km/h, corresponding to angular turn rates of approximately 1.3°/s, 2.9°/s and 5°/s. Passport tolerance for the turn indication at these reference points is not more than ±4°.

The pointer should return from an extreme position to the zero mark within 1.2–3 seconds. Deflection caused by a 90° transverse bank is limited to ±2°, and pointer stiction is limited to ±3°. The separate curved-tube inclinometer responds to lateral acceleration and gravity; its ball gives the crew a direct visual cue for slip or skid and helps assess whether a turn is coordinated.

Electrical supply, lighting and cockpit installation

The gyroscopic section is supplied from a three-phase 36 V AC, 400 Hz network. The product passport gives a voltage tolerance of +1.8/−3.6 V, a frequency tolerance of ±8 Hz and current consumption of no more than 0.2 A in each phase. The integrated red-and-white illumination uses 5 ± 0.5 V. Technical descriptions specify a readiness time of approximately three minutes after power is applied.

The variometer itself works from the static-pressure line, while the turn mechanism needs electrical power and the slip indicator works mechanically. Installation therefore requires both a sealed pressure connection and the correct electrical connector. Wiring, lighting voltage, mounting and circuit protection must be checked against the documentation for the individual airframe.

Documented applications and ordering checks

Technical material confirms DA-30P installations on the Yak-40 and Yak-42. Documentation also describes installation on the right pilot instrument panel of selected An-26 retrofit configurations, where it replaced the EUP-53 turn indicator. Applicability must not be transferred automatically to every modification of these types.

Before ordering, confirm the DA-30P marking, passport code 6A2.527.014 PS, scale version, electrical connector, static-pressure fitting, panel mounting and required documentation. The known passport delivery set includes the instrument, mounting hardware and a REMD24B10B1 mating socket. Reliable public data for the exact overall dimensions and connector pin count were not found, so these values should be checked from the offered unit or approved installation drawing.