What is a Helicopter PAPI?
One light unit beside the landing area, with four sectors of red and green. The pilot flies the helicopter until the light shows steady green.
The Helicopter PAPI is the helicopter approach path indicator (HAPI), the visual slope aid for heliports. Despite the name, it is not a miniature runway PAPI. It is one light unit that sends out four vertical sectors of red and green light, so the pilot reads a single signal that changes as the aircraft moves above or below the approach slope.
1One unit, one approach path
A runway PAPI is a bar of four units, each red or white. The HAPI is a single unit placed beside the landing area, on the side opposite the approach and facing across it. One HAPI serves one approach path, and its beam is split by height into the four sectors the pilot passes through on final.
2Read the colour, then the flash
Steady green means the helicopter is on the slope, and the on-slope sector is narrow, 45 minutes of arc. Flashing green means it is above the slope. Steady red means slightly below, and flashing red means below. The flashing sectors are the ones furthest from the slope, and the flash rate is at least 2 Hz so it cannot be mistaken for a steady light.
3Set the angle to clear the obstacles
The unit is adjustable in elevation. The angle is set so that, when the pilot drops out of the steady red sector into flashing red, every object in the approach area is still cleared. That makes the sharpness of the green and red transitions important: a blurred edge blurs the warning.
4Check the flash as well as the colour
Because flashing separates too high from on slope, and too low from slightly low, a failed flasher gives a false reading: a high helicopter would see steady green and read it as on slope. Check that all four sectors show the right colour and flash, that the unit is level and aimed at the set angle, that the lens is clean, that the frangible mounting is sound, and that the approach is clear. A flasher failure, a shifted angle or a dirty lens misleads the pilot on final.
| Pilot's position | Signal seen | Meaning |
|---|---|---|
| Above the slope | Flashing green | Too high |
| On the slope | Steady green | On the approach slope |
| Slightly below | Steady red | Slightly low |
| Below the slope | Flashing red | Too low |
Frequently Asked Questions
Q1What is a Helicopter PAPI?
A Helicopter PAPI is the helicopter approach path indicator, or HAPI, defined in ICAO Annex 14 Volume II for heliports. It is one light unit placed beside the landing area that gives the pilot visual slope guidance on final approach, using four sectors of red and green light, steady and flashing.
Q2How is a Helicopter PAPI read?
Flashing green means the helicopter is above the slope, steady green means it is on the slope, steady red means it is slightly below, and flashing red means it is below. The flashing sectors mark the positions furthest from the slope.
Q3How does a Helicopter PAPI differ from a runway PAPI?
A runway PAPI is a bar of four light units, each showing red or white, and the pilot reads the number of reds and whites. A HAPI is a single unit whose beam is split into four sectors of red and green, steady and flashing, so the pilot reads one signal rather than a row of lights.
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