SM 28-5

SM 28-5 miniature aircraft lamp

The SM 28-5 is a miniature aircraft incandescent lamp designed for use in aviation equipment, onboard lighting systems, signal circuits and other low-voltage electrical equipment. It is a small 28 V lamp used where compact size, vibration resistance and reliable light output are required. The lamp can be installed in aircraft and helicopter cabin lighting, instrument lighting, light-signalling equipment and various service lighting circuits.

SM 28-5 in aircraft lighting systems

The SM 28-5 is used in aircraft internal lighting and signalling applications. It may be installed in cockpit lights, cabin lighting units, panel lights, small signal indicators and auxiliary lighting devices. Since the lamp works from a 27–28 V onboard electrical network, it is suitable for many Soviet, Russian and Ukrainian aircraft electrical systems. Exact installation depends on the lamp holder, aircraft type and specific light unit.

Electrical characteristics of the SM 28-5 lamp

The lamp is rated for 28 V and has a nominal power of 5 W. Its light output is approximately 34–40 lm, depending on production batch and lamp version. The SM 28-5 may operate in DC circuits and in AC circuits where the applicable documentation allows it. In some references, operation on AC at 50 Hz is mentioned. Before installation, the lamp must be matched by voltage, power, base type and equipment documentation.

Mechanical strength and operating reliability

The SM 28-5 is designed as a small aircraft lamp with increased resistance to vibration, shocks and atmospheric pressure changes. This matters because aircraft lamps work in conditions that are less stable than normal ground electrical equipment. A similar-looking household or automotive lamp should not be used as a direct replacement unless the technical parameters and base type are confirmed. For aviation use, correct lamp marking and documentation are important.

Bulb shape and light output of SM 28-5

The lamp may have a cylindrical or spherical clear glass bulb depending on version and manufacturer. The transparent bulb provides direct light output without colored filtering. The lamp is mainly used as a light source inside another lighting unit, indicator or lamp housing. Final light color and direction often depend on the fixture, filter, diffuser or indicator lens into which the lamp is installed.

SM 28-5 base types and modifications

The SM 28-5 is produced with different bayonet base options. The SM 28-5-1 modification is associated with a B15s/18 single-contact bayonet base, while the SM 28-5-2 modification is associated with a B15d/18 two-contact bayonet base. These versions are not automatically interchangeable because the lamp holder and electrical contact scheme are different. When ordering, the required base type should be confirmed from the installed lamp or equipment passport.

Aircraft and equipment application

The SM 28-5 is not tied to one specific aircraft type. It is a universal lamp used across many aircraft, helicopters and special systems that use 27–28 V low-voltage electrical networks. It can be found on An-family aircraft such as An-24, An-26, An-72 and An-124; Il aircraft such as Il-76, Il-86 and Il-96; Tu aircraft such as Tu-134, Tu-154 and Tu-204; and Yak aircraft such as Yak-40 and Yak-42. It is also used on Mi and Ka helicopters, including Mi-8, Mi-24, Mi-26, Ka-27, Ka-32 and Ka-52 depending on configuration.

Non-aviation use of SM 28-5

Besides aviation, the SM 28-5 may be used in ground electric transport, special-purpose machinery, medical devices and laboratory equipment. In these cases, the lamp is valued for its compact size and mechanical resistance. It may be used in trams, trolleybuses, control panels, test equipment and industrial devices. However, for aircraft supply, aviation specification, marking and documentation should be prioritized over general industrial compatibility.

Product Type: Miniature aircraft incandescent lamp
Designation: SM 28-5
Russian Designation: СМ 28-5
Function: Light source for aircraft internal lighting, signalling and low-voltage equipment
Application / Where Used: Aircraft cabin lighting, cockpit lighting, navigation equipment, light signalling, ground electric transport, special equipment, medical and laboratory devices
Nominal Voltage: 28 V
Nominal Power: 5 W
Luminous Flux: Approx. 34–40 lm
Average Service Life: Not less than 150 hours
Bulb Shape: Cylindrical or spherical depending on version
Bulb Color: Clear glass
Current Type: DC and AC applications where permitted by equipment documentation
AC Frequency Reference: 50 Hz in some non-aviation references
Base Type, SM 28-5-1: B15s/18 single-contact bayonet base, 15 mm diameter
Base Type, SM 28-5-2: B15d/18 two-contact bayonet base, 15 mm diameter
Operating Features: Increased resistance to vibration, shock loads and atmospheric pressure changes
Compatible Aircraft / Equipment: An-24, An-26, An-72, An-124, Il-76, Il-86, Il-96, Tu-134, Tu-154, Tu-204, Yak-40, Yak-42, Mi-8, Mi-24, Mi-26, Ka-27, Ka-32, Ka-52 and other equipment with compatible 27–28 V lighting circuits
Interchangeability / Replaceability: Must be confirmed by lamp voltage, power, base type and equipment documentation
Condition: New / from storage depending on availability
Inspection / Testing: Visual check, filament continuity check, base inspection, contact check and functional lighting test
Technical Documentation: Product label, equipment documentation and quality documents as applicable

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In Stock — items available in stock at the Dubai warehouse are dispatched within 5–10 business days after receiving 100% prepayment.

Remote Stock — items available at our partners’ remote warehouses are supplied within an average of 30–45 business days after receiving 100% prepayment.

Pre-Order — made-to-order products are manufactured and delivered within an average of 45–60 business days. Payment terms: 50% advance payment to start production, with the remaining 50% paid before dispatch from the Dubai warehouse after full readiness for shipment.

Returns & Changes (Restocking Fee)
For selected items, a RESTOCKING FEE of 10% may apply in case of return, order cancellation, or changes to the order specifications. This condition applies only to certain products and is confirmed at the order approval stage.

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.