Pilot Controlled Papi Precision Approach Path Indicator 4 Fixture

The PCL-PAPI Precision Approach Path Indicator (PAPI) is a ground-based visual aid designed to assist pilots in maintaining a safe and consistent glide path during the final approach to landing at airports and heliports. This system utilizes a multi-light unit that projects two distinct colorsred & whiteto indicate the pilots position relative to the desired glide slope. The system is intended for use at small airfields or heliports where simplicity and cost-effectiveness are prioritized over more expensive complex systems. Comes in a 2 fixture(shown here) and 4 fixture versions.

What is a Two-Fixture PAPI?
A Precision Approach Path Indicator (PAPI) is a visual aid that helps pilots maintain the correct glide path during final approach and landing. A standard PAPI installation often uses four light units arranged in a row, but a two-fixture PAPI is a simplified version that provides the same essential guidance with fewer lights. The system is intended for use at small airfields or heliports where simplicity and cost-effectiveness are prioritized over more expensive complex systems. Comes in a 2 fixture(shown here) and 4 fixture versions.

How it Works
Each light unit produces two overlapping beams: one red (seen from lower angles) and one white (seen from higher angles).

By aligning the lights at different vertical angles, the pilot sees a combination of red and white depending on their position:
- Two White: Aircraft is above the glide path.
- One White / One Red: Aircraft is on the glide path.
- Two Red: Aircraft is below the glide path.

This simple three-state system gives the pilot an instant, intuitive indication of whether to correct their descent.

Advantages of a Two-Fixture PAPI
Compact and Cost-Effective: Fewer lights mean lower installation and maintenance costs compared to a four-light PAPI.

Ease of Installation: Requires less runway edge space and simpler electrical setup.

Clearer Guidance than Tri-Color VASI:
- A tri-color VASI uses a single fixture that shifts between amber, green, and red. While compact, it can be harder to interpret quickly and may suffer from color blur under certain conditions.
- A two-fixture PAPI gives discrete red/white indications, which are less ambiguous and easier to read in poor visibility or at a distance.

Better Pilot Familiarity: PAPIs (two or four unit) are widely used worldwide, so pilots are generally more comfortable with the red/white indication system than with tricolor VASIs.

Comparison: Two-Fixture PAPI vs. Tri-Color VASI

Feature	Two-Fixture PAPI	Tri-Color VASI
Light Units	2 fixtures	1 fixture
Indications	Red / White combinations	Amber / Green / Red
Ease of Interpretation	Simple, discrete steps (above, on, below)	Can be less intuitive, colors can blur
Pilot Familiarity	Very high (standardized worldwide)	Moderate, less common today
Cost & Installation	Moderate	Lower
Accuracy	Higher precision, even with 2 units	Less precise, especially at longer distances

A two-fixture PAPI strikes a balance: it is simpler and more affordable than a four-unit PAPI, while still providing clearer, more precise guidance than a tri-color VASI. If ultra precision is needed, perhaps for a short field relative to the aircraft landing, or high precision is required for other reasons, then the 4 fixture version is the way to go. See our FAQ for more details on the comparisons.

Dimensions: 3.07X5.62X17.91