Variable intensity PAPI?

[Two_dogs]

Just flew into a CTAF port and just as I was thinking, Gee, the PAPI is a bit bright, they suddenly dimmed to a much dimmer level.
This is the first time I have noticed this. Is this a new thing?

[Aimpoint]

No, I've been using ESP for years to change lighting intensity.

[Two_dogs]

It may well have been ESP, just found this from one manufacturer.
Maybe the airport staff heard my thought.

Control
The PAPI can be supplied with either manual or radio control. With the radio version of the PAPI, control is achieved either manually or by using the Master Switching Unit (MSU). A selector switch mounted on the control panel of the VIS PAPI enables either mode to be selected by the operator during deployment. Radio control is via a coded VHF receiver module mounted inside the electronics enclosure. The coding of the radio signal ensures a high rejection of radio interference from other transmissions and protects the unit from unauthorized operation either by accident or intent.

[YPJT]

THe PAPI intensity is usually controlled by PE cells co located with the PALC unit. I have seen airports that only have Jet charters and only during daylight hours hence they are left permanently on maximum intensity. They are as bright as buggery at night if on the day time intensity. Conversely, there are circumstances where they remain on night time intensity well after sunrise. This is a particular pain in the backside if the morning sun aligned with the rwy CL. THe sunlight can shine directly through the PAPI lenses and reflect back out cancelling the red / white PAPI colours.

Two_Dogs, the methods of control only refer to activation of the lights. None that I am aware of have any remote intensity control capability.

[Capn Bloggs]

Auto Day/Night intensity switch. :ok:

[Nose wheel first]

Ardmore Airport in Auckand (and others in NZ too) has/had variable intensity PAPI & RWY lighting. It's been 7 years since I last flew there but as I recall we did 5 clicks and held the 5th click while it cycled through an intensity range. Once the desired brightness was acheived you'd take your finger off the ptt button and it'd stay at that intensity until you or someone else changed it.

As I said, it's been a while so someone might be able to give more accurate info.

[YPJT]

Nose Wheel First,
Never heard of a system that provided that capbability, thanks:ok: I'll check with the Aussie suppliers to see if their systems have anything like it. Haven't seen it detailed on any ERSA entries though.

I wonder if crews would want to be dicking around with intensity of the PAPI on a 5 nm final?

[Fieldmouse]

PAL 118.1

To activate: transmit 5 pulses over a 3–4 second period. If runway lights fail to activate,

keep clicking transmit up to 10 times until lights turn on. Joining aircraft may not be able

to see lights if left on low intensity.

To change intensity: transmit similar 5 pulses but hold the 5th until desired intensity

reached, then stop transmission.

Runway: 03/21 APAPI 3.0°/TCH 46, LIL RWY

Aerodrome: WDI ABM THR RWY 21

Taxiway to SE apron, TWY M and TWY J marked with CL green reflectors.

No standby power available.

Funny no-one over here has picked it up. Funny. But not surprising. We are in the planning process of changing from Vasis to Papi so we might investigate this too.

[Tinstaafl]

Pilot controlled lighting (including intensity) is the norm in the USA. 3,5 or 7 clicks to activate the lights & set intensity. It's a great improvement on single intensity PAL as used in Oz.

[blackburn]

From the CASR Part 139 Manual of Standards (MOS):

9.3.1.2 Where PAL is used to activate visual approach slope guidance systems (T-VASIS or PAPI):
(a) activation of the PAL during daytime is to turn the visual approach slope
guidance system ON to Day intensity, and leave all other aerodrome
lighting extinguished;
(b) activation of the PAL during twilight is to turn the visual approach slope
guidance system ON to Twilight intensity, and turn all other aerodrome
lighting on to the only intensity available, or to Night intensity if multiple
intensities are available;