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Low Cost VASI/VAPI

HFS

Well Known Member
A little background:

I fly off a privately owned, public use (prior permission required) airport in the central San Joaquin Valley in California. It's used for ag work, as well as housing two King Air's on Part 135 tickets. 3600' x 50', lighted and paved.

I have been asked by the owners to look for an "affordable" (I know - oxymoron) VASI/VAPI that might be installed there for the charter operators. The runway is located at a rural farming headquarters with very little night lighting - going downwind there on a dark night is IFR (ask me how I know), and sometimes the crews for the airplanes are not familiar with the area - they need all the vertical help they can get.

Someone out there in VAF land must know of some options available.

Can you help?

Thanks

HFS
 
The “Three Board” system here at Dogwood (VA42) and Shannon (KEZF) is very good. We painted the boards neon orange and they are very visible with standard landing lights. We later took the extra step to add lighting on the boards.

No photo, but I’m guessing you have seen them. When the center (furthest away) board is lower than the two outside (closer) boards, you are too low. Too high and you are too high.

Carl
 
I would see what the FAA requirements are for charter ops. My understanding is that a FAA approved system is required and they can be pricey.
 
Part 135

The only requirement for VFR 135 operation is runway lights. Certification or no certification of VASI is irrelevant.
If you have GPS you can create your own quasi glide slope as follows:
Using a 1 1/2 mile final to give yourself plenty of room for "dark hole" at night you should be at 450' AGL in a 600 ft. minute descent. At 1 mile 300' and at 1/2 mile 150". Three times the distance and add two zeros or in the case of 1/2 mile intervals .5 x 3 and add one zero. Depending on runway length and exact location of airport reference point you will be a bit high on short final. As soon as the numbers are in the landing lights an adjustment can be made.
I used this off and on for 15 years of air ambulance flying, much of it into really marginal airports.
The GPS can also be used in OBS mode for runway alignment. If no weather info is available at 100' on final check your GPS ground speed, especially if the runway length is marginal. You can also create a GPS offset for downwind leg and if necessary fly a GPS distance arc from base to final.
 
The “Three Board” system here at Dogwood (VA42) and Shannon (KEZF) is very good. We painted the boards neon orange and they are very visible with standard landing lights. We later took the extra step to add lighting on the boards.

No photo, but I’m guessing you have seen them. When the center (furthest away) board is lower than the two outside (closer) boards, you are too low. Too high and you are too high.

Carl

Scotchlite reflective sheets (as seen on highways) might work well on the boards.
https://www.3m.com/3M/en_US/p/d/v000155288/

But that's not going to help a mile out. I would think the single light style that changes color couldn't be too hard to make. Name seems to be "tricolor". Just needs some angled baffles to separate the color zones.
 
Here’s a low cost starting point:
Pick up an old 35mm slide projector, color one half of the 35mm slide Red and leave the other half clear.
Prop the projector up at 3 to 4 degrees shining out on the approach end, fly the approach and stay just above the Red.
 
Slide Projector

The slide projector is an interesting idea - but I think the lamp will need to be pilot controlled and on a time-out timer. Those projector bulbs don't have great lifetimes. Leave it on all the time and you'll be putting bulbs in every week.
 
We had a three-board set-up at Sky Sailing years ago. Pretty much a daytime only thing, but pretty useful. Maybe with enough reflective tape and a pilot-activated flood light it could be seen a mile out at night.

It would be an interesting project to try to roll your own VASI by mounting a red spot light and a white spot light next to each other, with adjustable louvers over them that would blank out each color at the right glideslope angles.
 
would be an interesting optical/mechanical design challenge, using LED landing lights or similar and baffles. But don't forget to add tamper/tilt switches in case the mower hits it, etc. Lots of factors to consider.
 
Check with local airports and see if they have upgraded their systems lately. They could have the old units available for little or no cost.
 
https://www.kitplanes.com/diy-airport-glideslope-indicator/

Using parallax to achieve similar. Seems like a simple method. An interrupted bar of lights and a single light placed a distance in front or behind the bar. You could test the idea flipped 90 degrees to see how visible it is from a distance and the required dimensions, etc. No fancy optics needed.

I was going to suggest the same thing David - the ball-bar is easy to fly, and can be built passive for daytime only., or with lights (active) for night flying. Or….build it with both! It’s a good little engineering project, figuring out the brightness you need. With modern LED’s (bright!) it shouldn’t be that tough to come up with one if you want it day/night. For day only - its a piece of cake.
 
Maybe

The only requirement for VFR 135 operation is runway lights. Certification or no certification of VASI is irrelevant.
If you have GPS you can create your own quasi glide slope as follows:
Using a 1 1/2 mile final to give yourself plenty of room for "dark hole" at night you should be at 450' AGL in a 600 ft. minute descent. At 1 mile 300' and at 1/2 mile 150". Three times the distance and add two zeros or in the case of 1/2 mile intervals .5 x 3 and add one zero. Depending on runway length and exact location of airport reference point you will be a bit high on short final. As soon as the numbers are in the landing lights an adjustment can be made.
I used this off and on for 15 years of air ambulance flying, much of it into really marginal airports.
The GPS can also be used in OBS mode for runway alignment. If no weather info is available at 100' on final check your GPS ground speed, especially if the runway length is marginal. You can also create a GPS offset for downwind leg and if necessary fly a GPS distance arc from base to final.
"hand hacking" a VNAV path may be fine, if the visual approach surface, 20:1 is clear. However, at many airports without an instrument approach to that runway, the 20:1 is penetrated by unlit obstacles, usually trees. This is where a visual indicator is most useful. The VASI/ PAPI path can be tailored to clear the offending obstacles. Years ago, Maryland funded 3 board VASIs at a bunch of airports in the state. Some had 8ft florescent light fixtures added, and I recall them being visible from about three miles out.
 
Glidepath

I carefully researched every airport where I used the procedure. In some cases I used a steeper approach. At the old Zuni NM airport landing to the west I angled in to the the final until about 1/2 mile. At Crown Point NM landing to the north at night is nearly impossible due to very high terrain.
Primitive strips, very poor lighting, black hole, the procedure I posted worked well for me for many years.
For a steeper approach distance x four or even five.
Any time there was a better option I used the better choice.
Fixed wing air ambulance has a pretty dismal record of controlled flight into terrain.
 
I had seen one - and now cannot find the link but I think it was here on VAF - that used a set of LED Traffic lights shining through two C Purlins each colour. The red aimed at 2*& below, the green at 3* and the orange at 4* and above. The length of the purlins apparently made the distinction fairly clear.

I'll keep looking and update this post if I find it.

EDIT 1: Here's another thread on VAF about it, check out the bottom post re using fluro tubes - or LED strip lighting now.

EDIT 2: I KNEW I'd seen it. And it was here on VAF...Here it is, but without photos, they were hosted on Imageshack and went bye-bye when Imageshack did their merger years ago.
 
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