Runway Lighting Question!

K

KennyFlys

Guest
Why do we have them? Wait... that's not the question! A thought came to me while going through my CFI outlines and lesson plans.

Okay, we have ALSF-2 and ALSF-1. The only significant difference I can see is the lateral row at 500 feet and the two, narrower longitudinal rows on each side. The part I wonder about... when you're on approach to minimums, will those small differences make it for you considering the overall size of the ALS?
 
When you're coming down the slope in low IMC (especially at night) every little bit of light helps...especially when it gives you enough easily distinguishable lights to recognize it as an approach system, not just city lighting (remember, "lights in sight, continue"). So long as the 'rabit' is working, though, it doesn't really matter much to me which type ALSF it is...I just want to see the lights.
 
Why do we have them? Wait... that's not the question! A thought came to me while going through my CFI outlines and lesson plans.

Okay, we have ALSF-2 and ALSF-1. The only significant difference I can see is the lateral row at 500 feet and the two, narrower longitudinal rows on each side. The part I wonder about... when you're on approach to minimums, will those small differences make it for you considering the overall size of the ALS?

Great question! In really low visibility (think 1800 RVR) you won't see the entire ALSF-2 (or -1) while coming in, at least not all at once. The system extends between 2400' - 3000' before the runway, depending on the installation. In fact, when you take into account that some of your forward/downward visibility may be chopped off by the slope of the aircraft cowl, what you actually see out front could be very minimal.

In that case (low vis), the extra two rows of "red side row bars" and the 500' white roll bar (between the 1000' long white roll bar and the threshold) that the ALSF-2 has (and the ALSF-1 doesn't) could be very valuable cues in the transition from IFR to visual landing.
 
Great question! In really low visibility (think 1800 RVR) you won't see the entire ALSF-2 (or -1) while coming in, at least not all at once. The system extends between 2400' - 3000' before the runway, depending on the installation. In fact, when you take into account that some of your forward/downward visibility may be chopped off by the slope of the aircraft cowl, what you actually see out front could be very minimal.

In that case (low vis), the extra two rows of "red side row bars" and the 500' white roll bar (between the 1000' long white roll bar and the threshold) that the ALSF-2 has (and the ALSF-1 doesn't) could be very valuable cues in the transition from IFR to visual landing.
Tonight, I passed by 8L ATL and looked at the lights. I see the features clearly there but then I was driving only 45-50MPH.

Last year, I had the pleasure of shooting that very same ILS approach... in a Skyhawk. I recall seeing the red side bars but had only an approach speed of about 75 Kts at that point and I wasn't even close to flaring.

In the case of an airliner, they are already flaring and nose high so the view of those last thousand feet (probably much more) of lights are probably not even visible. Even being flat, earlier in the approach, I don't see the lights being as helpful. As you state, the cowl interferes with the view as well which I hadn't even considered. That's there regardless of required RVR of 4,000 on this approach.

But, assuming you have a full view of the ALS, I can see how beneficial it is in transitioning to visual. I just wonder how often an airliner stays flat enough to see the entire set of lights.

I know I'm taking this a lot further than needed. But I do wonder about it from the perspective of a heavy jet making an ILS and looking for these light patterns.

As Teller said, the rabbit is the nail... the rest almost seems like gravy.
 
I just wonder how often an airliner stays flat enough to see the entire set of lights.

My understanding is [the jet flyers can (WILL) correct me if this is wrong] that they have a visual eyepoint alignment indicator to ensure that their seat height is set for a consistent viewpoint out the front window for reasons just such as this...
 
My understanding is [the jet flyers can (WILL) correct me if this is wrong] that they have a visual eyepoint alignment indicator to ensure that their seat height is set for a consistent viewpoint out the front window for reasons just such as this...
Greg was answering my question in the chat room a bit ago. He was saying their perspective is so close to the nose, they really have a complete and unencumbered view of the entire approach.
 
Greg was answering my question in the chat room a bit ago. He was saying their perspective is so close to the nose, they really have a complete and unencumbered view of the entire approach.
That's true. Almost every pilot I fly with raises the seat at least a little (depending on the hieght of the pilot) during the decent. Sitting at the pointy end of a jet does indeed provide quite the view of the approach. In the 707 type aircraft, the approach is flown at an almost flat attitude. Only 2 or 3 deg nose up. The "flare" is minimal as well due to the nice cushion of air under the jet when we enter ground effect. All we have to do is set the deck angle and pull power and gravity does the rest. Bottom line, the foward vis is good, and as long as we see "cues" the approach continues.
 
Greg was answering my question in the chat room a bit ago. He was saying their perspective is so close to the nose, they really have a complete and unencumbered view of the entire approach.

I know in the 1900, even fully in the flare we can easily see the runway directly in front of us. I've jumpseated in 737s, 757s, A319, A320, and a SF340...in all cases, even back at the back of the flight deck, the nose is so short and the cockpit so high the view is almost unobstructed through the flare. They're pretty much designed to give the pilots the best visibility possible (no pilot would want to fly a plane that loses visibility of the TDZ on three mile final...too much risk for a runway incursion, and it would be really tough to judge your alignment with the centerline if you lost that much vision that early).
 
The ALSF-2 is what we call a "dual mode" ALS. When it is in ALS mode it includes all off the lights. When it is in SSALR (Shortened, Simplified, Approach Light System, w/ RAIL RAIL=Runway Alignment Indicator Lights) it basically becomes a MALSR.

The light stations on a MALSR are 200' apart. The light stations on an ALS are 100' apart. In SSALR mode every other light station is turned off, along with all of the red lights, and every other threshold light. The ALS has 15 flashers. In SSALR mode it has 5 flashers, just like a MALSR.

When the ALS is on step 5 (the highest step) it uses nearly 175,000 watts of power. The power coming into the lighting substation is 4,160 volts. The current regulators use one phase to ground, so each lighting loop has a 2,400 potential. Don't mess with the wires!

Having two modes serves two purposes. It saves electricity and maintenance cost by running fewer lights when the conditions don't require all of the lights. It also lets the controllers configure parallel runways differently for distinction.

I know I've gone into way more detail than anyone wants. The topics rarely reach my area of expertise. I have been an F.A.A. technician for the past 20 years.
 
Last edited:
I know I've gone into way more detail than anyone wants. The topics rarely reach my area of expertise. I have been an F.A.A. technician for the past 20 years.
Ah, but you see, now I can impress women at parties! ;)

All info is good.

Fly safe!

David
 
The ALSF-2 is what we call a "dual mode" ALS. When it is in ALS mode it includes all off the lights. When it is in SSALR (Shortened, Simplified, Approach Light System, w/ RAIL RAIL=Runway Alignment Indicator Lights) it basically becomes a MALSR.

The light stations on a MALSR are 200' apart. The light stations on an ALS are 100' apart. In SSALR mode every other light station is turned off, along with all of the red lights, and every other threshold light. The ALS has 15 flashers. In SSALR mode it has 5 flashers, just like a MALSR.

When the ALS is on step 5 (the highest step) it uses nearly 175,000 watts of power. The power coming into the lighting substation is 4,160 volts. The current regulators use one phase to ground, so each lighting loop has a 2,400 potential. Don't mess with the wires!

Having two modes serves two purposes. It saves electricity and maintenance cost by running fewer lights when the conditions don't require all of the lights. It also lets the controllers configure parallel runways differently for distinction.

I know I've gone into way more detail than anyone wants. The topics rarely reach my area of expertise. I have been an F.A.A. technician for the past 20 years.

Really cool details, none the less. And seriously...what woman wouldn't be interested in a long discourse on the specs of an ALSF?
 
Ah, but you see, now I can impress women at parties! ;)

All info is good.

Fly safe!

David


Somehow I have doubts as to whether women at parties will be interested in the wattage of an ALS or how far apart the light stations are!

Now ask me about the ALS monitoring system and current regulators. I can really bore you with the details on that!
 
Somehow I have doubts as to whether women at parties will be interested in the wattage of an ALS or how far apart the light stations are!

Now ask me about the ALS monitoring system and current regulators. I can really bore you with the details on that!
Bore us, please! I'm actually curious. :)
 
Somehow I have doubts as to whether women at parties will be interested in the wattage of an ALS or how far apart the light stations are!

Now ask me about the ALS monitoring system and current regulators. I can really bore you with the details on that!

I've been curious...can you tell me a little about ALS monitoring systems and current regulators? I know it's an obscure topic, but I've always been curious.
 
A lot happens behind the scenes that the pilots never see when the weather gets bad.

Our backup generators become "prime power" when the conditions are Cat-II or worse. That means that we put our generators online and the power company becomes the backup. This is to prevent a power outage with a plane on final.

The automation that controls the system also monitors the lights in the system. The system is divided into three loops (5 on the new ones). Each loop is fed from a different current regulator. The system counts the lights out. It lights a caution light in the tower cab if there are 5 lights out in the same loop. It lights a failure light if there are 6 or more lights out in the same loop. The monitor can't turn the system off, but for legal purposes the system is out of service when it reaches 6 lights out. My job is to make sure we never reach that many out! It also monitors the flashers. We can't have more than 2 consecutive or 3 random flashers out.

The flashers have a power supply that puts 2000 volts DC across the tube. It sends a 14KV trigger to ionize the gas in the tube. It stays illuminated until the capacitors on the 2000 volt grid are discharged. It then recharges for the next cycle. It cycles twice per second.

One interesting thing that people have trouble grasping is that the "intensity" changes in the flashers are really changes in the length of the flash. It really isn't brighter even though it appears that way. The system puts more capacitors in the circuit to step up the flash. It takes slightly longer to discharge, so the flash gets longer but not brighter. The length of the flash is based on the RC time constant in the circuit.

Flashers are dangerous to work on. Besides the obvious electrical hazards from the high voltage, there is a risk to eye damage from being too close to the tube. We never look directly into the tube when working around them.

So, are you ready to take the certification exam now? :)
 
Last edited:
So, are you ready to take the certification exam now? :)
Sure... right after you provide probably another few hundred dissertations! :)

When you refer to flashers, I assume you mean the strobe lights? Of those, I see the rabbit and the REILs with the former definitely sequential. But, are the REILs random? Both sides flash simultaneously.

If I'm all wrong here, what else is there that uses "flashers"?
 
When you refer to flashers, I assume you mean the strobe lights? Of those, I see the rabbit and the REILs with the former definitely sequential. But, are the REILs random? Both sides flash simultaneously.

If I'm all wrong here, what else is there that uses "flashers"?

The "R" part of MALSR stands for runway alignment indicator lights. There are 5 of them on a MALSR. There are 15 of them in an ALS. The REIL's are not random. They do flash simultaneously. The "flashers" in each of these systems work exactly the same way. They receive their timing signals from various types of control cabinets. The ALS includes a monitor signal so the controller will know if they failed to flash.

Hey, this is a family oriented Board.
Good one! :)
 
For some reason, I suddenly thought of Inspector Columbo in his long overcoat.

You are telling your age now! That show was popular in the '70's. (I remember it too....)
 
The "R" part of MALSR stands for runway alignment indicator lights. There are 5 of them on a MALSR. There are 15 of them in an ALS. The REIL's are not random. They do flash simultaneously. The "flashers" in each of these systems work exactly the same way. They receive their timing signals from various types of control cabinets. The ALS includes a monitor signal so the controller will know if they failed to flash.

Good one! :)


Has there ever been any thought given to either sheilding or pointed the REILs a few degrees away from the final approach path or angleing them a few degrees above or below the glide path....it seems like every time I get within a few hundred feet of the REILs (which is a few hundred feet from the runway) I have to squint and focus really hard on the center of the runway to keep from being blinded by the lights? I love them when I'm trying to find the runway, but kind of hate them once I've found it.
 
Are the approach lights at your airport F.A.A. maintained or airport maintained? The F.A.A. specs call for the REILS to be aimed 15 degrees away from the runway and 6 degrees up.
 
Are the approach lights at your airport F.A.A. maintained or airport maintained? The F.A.A. specs call for the REILS to be aimed 15 degrees away from the runway and 6 degrees up.

I have no idea...it has a part time FAA control tower, if that means anything. It really doesn't seem like 15 degrees, though...

Are they sheilded at all from spilling into the approach coridor, or do they just focus wide angle beams 15 degrees out?
 
They are usually not shielded. They are wide angle beams. The idea is to help locate the runway, so I guess narrow beams wouldn't serve the purpose as well.

They do have baffles (shields) available for locations that are a problem. I don't know if yours need baffles or just better aiming. I wish you were closer so I could see it.

What airport and runway are you talking about? I can pass the word on to my counterparts in the area and see if they will check it out.
 
It's KLEB, Lebanon, NH, runways 7/25 and 18. 18 is the one I notice the most since that's the ILS runway. There is always the chance that they're fine and that I'm just a wuss, but REILs frequently annoy me.
 
Jeff, I know we're supposed to abandon the *** system. But I need to point out that NOBODY nowhere can discuss lighting systems like you.

Sometimes when you read a thread, you can just TELL the guy's an expert.

Thank you for enrichening my day.

Bruce
 
Hi Bruce! It is great to hear from you! I have spent many hours reading the medical posts. I have learned a lot from you the past couple of years!

It is rare that anyone wants to hear from us, so I tend to go into a lot of detail when someone shows interest!

Yes, they are phasing us out. I hope to hang on for a few more years, but I don't know if we'll be around long enough for me to finish. There were over 16,000 technicians in the F.A.A. when I started nearly 20 years ago. Now there are 6,000 of us.

The Flight Service Stations are already gone. The latest I heard was that 2,000 of the 2,200 VOR's are going to be phased out soon.

I don't know what the future holds, but it appears as though I may be looking for a new job one of these days. I'm too old to begin a flying career. I still don't know what I'm going to do when I grow up!
 
It's KLEB, Lebanon, NH, runways 7/25 and 18. 18 is the one I notice the most since that's the ILS runway. There is always the chance that they're fine and that I'm just a wuss, but REILs frequently annoy me.

I'll find out who maintains them and pass it on to the office up there.
 
Jeff, I know we're supposed to abandon the *** system. But I need to point out that NOBODY nowhere can discuss lighting systems like you.

Sometimes when you read a thread, you can just TELL the guy's an expert.

Thank you for enrichening my day.

Bruce

I'm with you on that--interesting read.
 
I just wish I knew more about these systems to ask educated questions.

Ask away. I don't mind! It is flattering to have someone show interest once in a while. I like to let people know we exist. When people hear that I work for the F.A.A., they immediately state, "so you're an air traffic controller". I always have to respond with, "no there are 6,000 of us that no one knows exists, and the F.A.A. is phasing out".

Get out your credit cards for approach equipment brought to you by Raytheon, (or your contractor of the day)!
 
Well that brings up a question right there...what exactly is your official title, and why are they phasing you out? Seems like people with intimate knowledge of how approach systems work would be fairly important to keeping the approach systems working! Do you just work with the lighting system or all of the infrastructure (rwy markings, LOC/GS, VORs, NDBs, etc)?
 
Well that brings up a question right there...what exactly is your official title, and why are they phasing you out? Seems like people with intimate knowledge of how approach systems work would be fairly important to keeping the approach systems working! Do you just work with the lighting system or all of the infrastructure (rwy markings, LOC/GS, VORs, NDBs, etc)?

My official title has changed three times, even though my job has been the same. My official title is "Airway Transportation Systems Specialist".

They are phasing us out because of the company executives from the contractor paying off the right people at the top in the F.A.A. Is it a coincidence that Ratheon has an office right down the street from the capital building in Washington DC?

Of course the "official" line is that they are doing it to save money. In reality, the contractors aren't providing the same service. For example, Lockheed Martin claims to be providing the same service cheaper than the F.A.A. In reality they aren't providing the same service at all. Besides the wait times that you already know about, they don't provide many of the services that the F.A.A. Flight service did behind the scenes, such as monitoring VOR's and maintaining backup power systems.

My accusation of pay off at the top can be illustrated by watching where the F.A.A. administrator goes when she leave the F.A.A.

To answer your last question, my "official" duties don't specify which systems I work on. Officially we can all be assigned anything. In reality, we each fall into one of three areas. The radar technicians do just that. It is a specialty all its own. Then we have people who just do VOR's, ILS's, and communications. Then there is my group. We do approach lighting systems, standby power (generators and UPS's), electrical distribution (both on the field and in the buildings), heating, and air conditioning. Backup power and approach lighting are the most important functions of my job.

I am one of the few that fly. Once in a while I get called out on emergency calls to distant airports. That works out nicely because the F.A.A. gets a technician on site quickly and I get to fly and have them pick up part of the tab!
 
Last edited:
I knew nav systems were monitored by the feds, but I never knew any of the rest of that stuff was within the spectrum of the FAA. I guess I had always assumed it was up to the airport's onsite technitions to keep things up and running. Is that a GS- position? How is it decided what airports are covered by the FAA and which ones Raytheon handles? Is it mostly engineers that get into this field?
 
I knew nav systems were monitored by the feds, but I never knew any of the rest of that stuff was within the spectrum of the FAA. I guess I had always assumed it was up to the airport's onsite technitions to keep things up and running. Is that a GS- position? How is it decided what airports are covered by the FAA and which ones Raytheon handles? Is it mostly engineers that get into this field?


At airports where the F.A.A. has equipment, we (F.A.A.) maintain approach lighting. The airport authority maintains the runway/taxiway edge lighting. The F.A.A. maintains the ILS's and other Navaids too.

I was using Raytheon as an example above. There is a large group of contractors, including Raytheon, that have been trying to get the contracts for years. They are getting it, bit by bit. First the small towers, then the Flight Service. I don't know it for fact, but I have been told that some of the F.A.A. systems in Alaska are maintained by contractors.

You are correct in that it is the airport's on site technicians that maintain it at airports that don't have F.A.A. owned systems. I don't know how it is decided which ones will be F.A.A. and which ones aren't. Those decisions are made far above my level. They have never asked me!

KPDK (and I am sure there are others) is mixed up. The F.A.A. maintains the ILS's and some of the approach lighting. The airport authority maintains the others. At KAHN the airport maintains the ILS, but the F.A.A. maintains the VOR, VASI's, and PAPI's.

At the worker level, we used to be GS-12's. We went to "pay banding" in the late '90's. Those of us who had been around a while got a good raise. Those who were just beginning their careers took a pay cut. The trouble is that it was the end of the road. There are no more "step increases". Eventually inflation will eat up our standard of living. The "cost of living increases" seem to never keep up with inflation. The bands compared to other agencies that are still on the GS scale put me at a mid 13 or low 14. The band has a huge range from bottom to top. They seem to hire the new ones at the bottom of the band. Since there is no way to move within the band, it will be hard to retain the talented technicians. The good ones will move on to better places. Management is very short sighted in this regard. They may save a few bucks now, but it will cost in quality in the long run.

The technical work force in the field used to mainly be military trained technicians. Many still are, but a lot come from various colleges and trade schools. We do have a fair number of engineers. There is a huge engineering staff at the regional office.

The airports with ILS's that are not F.A.A. owned hire whoever they want to maintain them. There is a small avionics shop near here that is phasing out of aircraft avionics. He has a big business maintaining ILS equipment for numerous airports. I may do something similar when the F.A.A. gets rid of us. I am hoping that the timing works out where I can retire from the F.A.A., then do some contract maintenance on airports. I am not sure if the F.A.A. is going to give me enough time for that.
 
Last edited:
jhempel,

I completed lighting and signage contracts at the KWWD and KMIV airports. Just working out the details and getting the funding squared away for an emergency gen set at WWD with the NYADO. It should hit the streets in 60 days for bid.

The whole electric vault just overwhelms me....so much tech stuff and all that sparky stuff.
 
jhempel,

I completed lighting and signage contracts at the KWWD and KMIV airports. Just working out the details and getting the funding squared away for an emergency gen set at WWD with the NYADO. It should hit the streets in 60 days for bid.

The whole electric vault just overwhelms me....so much tech stuff and all that sparky stuff.

I am curious, what do you do?
 
Back
Top