Green & White VASIS??

[Safety Guy]

Has anyone here ever seen a VASIS light system which uses green and white lights, instead of red and white? Apparently that's what they have at La Cieba, Honduras. My question is, which colour is "bad"??

Can anyone help?

Thanks,

SG

[The Greaser]

Apparently there is a high incidence of colour blindness in that neck of the woods.

[fireflybob]

No green means you are exceedingly low since the lights are now shining through the grass between the observer and the runway!

[Safety Guy]

Real helpful guys, thanks!

[blackmail]

hello safety guy,

it could be a tri-color visual approach slope indicator: (TRCV)

quote jepp in introduction chapter:"tcrv is normally a single light unit located on the left side of the runway".

amber: above glide path
green: on glide path
red: below glide path

caution note added: "when the aircraft descends from green to red, the pilot may see a dark amber color during the transition from green to red".

another possibility is the "pulsating visual approach slope indicator:(PLASI) but only with white & red lights, also located normally on left side of rwy.

pulsating white: abv glide path
steady white: on glide path
steady red: slightly below glide path
pulsating red: below glide path

caution note this time: "when viewing the pulsating visual approach slope indicators in the pulsating white or pulsating red sectors, it is possible to mistake this lighting aid for another aircraft or ground vehicle. pilots should exercise caution when using this system".

last remark: vasi/papi are certified only from about 4nm out cfr obstacles & if non-std coverage a caution note is usually added.
vasi is normally ok till 200ft agl.
papi is ok till 100ft agl.
and, yes, growing grass can obscure correct viewing of colors, as can hazy wx conditions(prisma effect).
the system can be off or on maintenance or even worse, not installed at all, see paris orly where no vasi/papi system exist on the main landing rwy's.

and safety guy, cfr some funny comments of some previous posts: don't worry, quote the bible as jesus was saying on mount golgotha: "forgive them, my lord, they do not know what they are doing".

[Safety Guy]

Wow, thanks for the detailed response, blackmail! I wondered about the TRCV, but it was the white light that threw me off.

As for the humourous resposes, I know that they "know not what they do". I just assumed that a Tech Log forum would only be frequented by knowledge freaks and techno geeks, not winged comedians. Wrong again!

[bobrun]

Did a trip to Roatan, Honduras, last Sept. and the rwy was equipped with the usual red/white papi.....Also went to La Ceiba about a year ago, and the rwy at that time also had the usual red/white papi.....but it may have changed since....

[Thunderbug]

Overheard a conversation to ATC in the mid-west (USA) recently - the upshot was that a few months back an aircraft had left the runway and rearranged the PAPIs - unfortunately when they replaced them they managed to install one of them upside down!

Really helpful! :confused:

T'bug