APM-1

Cockpit inscription and marking illumination by APM-1

The main function of the APM-1 is to provide controlled illumination of panel inscriptions and symbols. In aircraft cockpits, many switches, control panels and instrument boards must remain readable without creating glare or distracting the crew. The APM-1 directs light into the light-guide elements of the panel, making the required markings visible. This type of illumination is important during night operation because the crew must identify controls quickly while preserving normal visual orientation in and outside the cockpit.

Red and white light versions of APM-1

The APM-1 is produced in versions with different light colors. The red-light version, APM-1 red / 9S2.424.012-03, is used where night vision adaptation must be preserved. Red lighting reduces the risk of disturbing the crew’s dark adaptation during night flights. The white-light version, APM-1 white / 9S2.424.012-04, provides neutral illumination where standard readable panel lighting is required. When ordering, the required color version should be stated clearly because the red and white versions serve different cockpit lighting purposes.

Lamp and low-voltage operation of APM-1

The APM-1 uses an SM6.3-1.4 aircraft incandescent lamp as its light source. The fitting operates from a low-voltage DC supply not exceeding 5.5 V. This makes it suitable for cockpit panel lighting circuits where brightness is controlled and distributed across multiple small lighting points. The unit is compact and low-power, but correct voltage is important. Excessive voltage may shorten lamp life, while poor contact, wiring damage or incorrect supply can cause dim light or intermittent panel illumination.

Compact construction of the APM-1 fitting

The APM-1 is a very small cockpit lighting component, with dimensions of 16.5 × 40 mm and a weight of only about 14 g. The unit includes a 2-meter lead wire, which allows installation inside panels and connection to the cockpit lighting circuit. Its compact size makes it suitable for dense instrument panels and control consoles where space is limited. During maintenance, technicians normally check the lamp, wire condition, insulation, mounting point, contact quality and correct light output.

Operating environment of APM-1

The APM-1 is designed for aircraft cockpit conditions and operates across a temperature range from −60 °C to +60 °C. This allows it to remain serviceable in cold-start conditions, high-altitude environments and hot cockpit areas. Although the unit is small, it must withstand vibration, temperature changes and long service operation. The assigned resource is specified as 4500 flight hours within 5 years of operation. For replacement, both technical condition and calendar/service limits should be considered.

Application of APM-1 in airplanes and helicopters

The APM-1 is used in cockpit lighting systems of airplanes and helicopters where light-guide panel illumination is installed. It can be fitted in control panels, switch panels, instrument boards and other cockpit areas requiring localized inscription lighting. Exact applicability depends on the aircraft electrical and panel lighting design. Before replacement, the required color, drawing number, lamp type, voltage and acceptance category should be checked against the aircraft maintenance documentation.

Supply and documentation for APM-1

For procurement, the APM-1 should be ordered by full designation and color version: APM-1 red or APM-1 white. It is also useful to specify the drawing number, required acceptance type, condition and documentation. Depending on the order, the unit may be supplied as new, from storage or in another agreed condition. For aviation use, the product passport or manufacturer documentation should confirm designation, version, acceptance and suitability for installation in the cockpit lighting system.