Portable PAPI

The Portable PAPI is a self‑contained, transportable version of the standard Precision Approach Path Indicator. It consists of four light units (or sometimes two, in a portable APAPI configuration) mounted on a lightweight, collapsible tripod or base, with integrated power sources (batteries, solar panels, or portable generators) and control electronics. The system is designed to be rapidly deployed and calibrated without the need for permanent foundations, underground cabling, or fixed power infrastructure.

Portable PAPI is ideal for temporary airfields, military forward operating bases, humanitarian relief operations, emergency landing strips, and any situation where a permanent visual glide slope system is not feasible. Despite its portable nature, it delivers the same high‑intensity, precision beam pattern and colour‑transition accuracy as its fixed counterpart, ensuring safe approaches for both fixed‑wing and rotary‑wing aircraft.

A portable PAPI exists to bring precision glide slope guidance to places where a permanent installation isn't possible or isn't yet justified — a disaster relief strip, a forward operating base, or a temporary runway supporting an event or emergency. Without it, pilots approaching an unfamiliar or hastily prepared airstrip would have to rely on non-visual approach aids or judgement alone, both of which carry a much higher margin for descent-angle error, especially in poor light or unfamiliar terrain.

By replicating the same red/white colour transition and beam accuracy as a fixed installation, the portable system lets a pilot approach with the same confidence and technique they'd use anywhere else, without needing special training or procedures just because the glide slope indicator happens to be sitting on a tripod rather than a permanent foundation.

Portable PAPI is used in a wide range of temporary and rapidly changing operational environments:

• Military forward operating bases – where runways are temporary and need rapid setup.
• Humanitarian relief operations – after natural disasters, where permanent infrastructure is damaged.
• Emergency landing strips – for medical evacuation or disaster response.
• Temporary airfields for events – airshows, firefighting, or construction projects.
• Remote or austere locations – where power and cabling are not available.
• As a backup or supplement to fixed PAPI – for maintenance or contingency operations.

Rather than a fixed frangible mount on a permanent base can, Portable PAPI units sit on ground-bearing skids, trailers, or tripod-style frames that can be positioned directly on the surface without excavation or cut-in works. Set-out still follows the same principle as fixed PAPI — a wing bar at a set lateral offset from the runway edge and a setback from the threshold chosen to give the correct glide angle over the aiming point — but the position is established with a portable survey or GPS reference rather than a permanent as-built survey, and the bar is levelled unit-by-unit using built-in bubble levels or self-levelling mounts. Power is typically supplied by an integral battery pack, solar panel, or portable generator rather than mains-fed constant current regulators, allowing the whole system to be set out, aligned, and made operational within a short window, then struck and relocated once the runway or task is no longer needed.

Portable PAPI functions on the same optical principles as fixed PAPI, but with integrated power and control systems:

• Optical Design: Each light unit contains a high‑intensity LED array or halogen lamp with precision optics that project a beam with a sharp red/white transition. The transition angle is set to the desired glide path (typically 3° but adjustable).
• Colour Indication: The four‑light display provides the standard red/white combination:
  • All white – well above the glide path.
  • 3 white / 1 red – slightly above.
  • 2 white / 2 red – on the correct glide path.
  • 1 white / 3 red – slightly below.
  • All red – well below.
• Power and Control: The system is typically powered by rechargeable batteries (with solar panels for extended operations) or a portable generator. A built‑in control unit provides intensity adjustment (day, twilight, night) and may include remote control or wireless monitoring capabilities.
• Deployment: The units are placed on a level surface at the required distance from the runway threshold, aligned using a built‑in compass and spirit level or a portable theodolite. The entire system can be set up by two people in under 30 minutes.

Portable PAPI keeps the same fixed-optics signal as permanent PAPI — each unit's lens/shutter is still tilted to a specific elevation so the red/white transition sits at the right point — but replaces the CCR series circuit with a self-contained power and control chain. A battery bank (charged by solar panel, mains, or topped up by a portable generator) feeds a built-in control unit, which is the electronic equivalent of the CCR: it sets one shared brightness level across all four units for day, twilight, or night, and on models with wireless monitoring, reports state of charge and unit status to a handheld or remote link rather than to an ALCMS. Because there's no buried series loop, there's also no loop-voltage fault detection — each unit is typically wired to the control unit individually, so a lamp or driver failure is more often caught by directly checking that unit than inferred from circuit behaviour. The part that still has to be done by hand, every deployment, is optical alignment: units are levelled and aimed using a built-in compass and spirit level or a portable theodolite, since the elevation that encodes the glide path is set fresh each time the array is placed rather than fixed permanently in the ground.

Each portable unit is a compact, weatherproof housing in lightweight aluminium or high-impact polymer, built around the same lower red-filter / upper white-glass optical split as a fixed PAPI, with a built-in spirit level and pitch-adjustment mechanism for setting the glide-path angle in the field without survey equipment. The housing sits on a folding tripod or ballasted skid base rather than a buried frangible mast, so the whole unit can be man-carried, levelled, and aimed by two people without excavation or concrete footings. Power comes from an integrated 12V/24V battery pack, charged by an attached solar panel or a portable generator rather than a mains-fed isolating transformer, and units link back to a small field controller for step-brightness or on/off control. This self-contained design is intended for temporary glide-path guidance — during runway works, at deployed or expeditionary airfields, or as a fallback when a fixed PAPI is out of service — and is designed to be struck and removed rather than left as a permanent installation.