Use of alternating red-green light signal

Discussion in 'Change to my Frequency...' started by PeterNSteinmetz, Apr 8, 2020.

  1. PeterNSteinmetz

    PeterNSteinmetz Cleared for Takeoff

    Joined:
    Sep 9, 2015
    Messages:
    1,493
    Location:
    Tempe, AZ
    Display Name:

    Display name:
    PeterNSteinmetz
    I have been memorizing the light gun signals and my wife asked when an alternating red-green for “exercise extreme caution” is actually used.

    Has anyone actually ever seen or used this ? And why? What is an example that calls for this?
     
    Palmpilot likes this.
  2. Brad W

    Brad W Pre-takeoff checklist

    Joined:
    Nov 19, 2019
    Messages:
    469
    Display Name:

    Display name:
    BLW2
    I'll bet every pilot has wondered that in their training....
    great question
     
    PeterNSteinmetz likes this.
  3. WannFly

    WannFly Final Approach

    Joined:
    Nov 28, 2016
    Messages:
    5,198
    Location:
    KFAR
    Display Name:

    Display name:
    Priyo
    It means you are cleared to land, but use caution, Harrison Ford is on short final
     
  4. jsstevens

    jsstevens Final Approach PoA Supporter

    Joined:
    May 18, 2007
    Messages:
    5,337
    Display Name:

    Display name:
    jsstevens
    Shouldn't that be a caution for your taxi clearance? :)
     
    GRG55 and WannFly like this.
  5. jordane93

    jordane93 Final Approach

    Joined:
    Sep 9, 2013
    Messages:
    9,579
    Location:
    Long Island, NY
    Display Name:

    Display name:
    Jordan
    I’ve heard the light gun signals are barely visible.
     
  6. GRG55

    GRG55 Final Approach

    Joined:
    Dec 29, 2015
    Messages:
    7,630
    Display Name:

    Display name:
    Aztec Flyer
    That explains it! I've never actually seen one. :D
     
    WannFly likes this.
  7. wanttaja

    wanttaja En-Route

    Joined:
    Jun 7, 2008
    Messages:
    3,088
    Location:
    Seattle
    Display Name:

    Display name:
    Ron Wanttaja
    I flew in to Boeing Field once using light gun signals. It's a bright dot; on a sunny day, the world is full of bright dots. My problem is that I hadn't flown into the airport before, and didn't know where the tower was. When I finally realized its location, I saw a dot of light on the glass.

    The light didn't seem to have color, though...that is, I didn't really see it is "green." Just seemed like a white dot.

    Ron Wanttaja
     
  8. Ryanb

    Ryanb Touchdown! Greaser! PoA Supporter

    Joined:
    Jul 21, 2010
    Messages:
    11,461
    Location:
    Tennessee
    Display Name:

    Display name:
    Ryan
    I’ve only seen light gun signals in training when specifically asking the tower to use them for us. It was at night, so I recall them being quite visible.
     
  9. frfly172

    frfly172 Touchdown! Greaser! PoA Supporter

    Joined:
    Oct 22, 2008
    Messages:
    14,170
    Location:
    mass fla
    Display Name:

    Display name:
    ron keating
    Go out in the daylight and ask the tower for a test.Doubt you’ll see the colors.
     
    PaulS likes this.
  10. Matthew

    Matthew Touchdown! Greaser!

    Joined:
    Apr 18, 2005
    Messages:
    16,277
    Location:
    kojc, kixd, k34
    Display Name:

    Display name:
    Matthew
    I've had light gun signals both at night and during the day. At night, it's pretty visible, but you have to know where to look or you'll miss it. At night it might be hard to find the tower and if it's off on the passenger side it can be tough to get a visual on it. During the day it's worse, but it can be done - you really do need good eyesight and no color blindness, though.

    It's a simple request to the tower for light signals.
     
  11. pmanton

    pmanton Cleared for Takeoff

    Joined:
    Jun 7, 2008
    Messages:
    1,195
    Location:
    Indian Hills Airpark Salome, AZ
    Display Name:

    Display name:
    N1431A
    I’ve heard the light gun signals are barely visible.
    I'm an old fart having learned to fly in the mid 50's. I trained at a towered airport in planes without electrical systems. No problem at all with light signals back then.
    Of course the guys in the tower knew where to point it, and the guy in the plane knew where to look.
     
    dtuuri likes this.
  12. bflynn

    bflynn Final Approach

    Joined:
    Apr 24, 2012
    Messages:
    5,647
    Location:
    Fuquay Varina, NC
    Display Name:

    Display name:
    Brian Flynn
    Would this be suggesting there are times when I'm not using caution when landing at a controlled field without a radio? (joke)

    FAA order 7710.65

    3−2−2. WARNING SIGNAL
    Direct a general warning signal, alternating red and green, to aircraft or vehicle operators, as appropriate, when:
    NOTE− The warning signal is not a prohibitive signal and can be followed by any other light signal, as circumstances permit.
    a. Aircraft are converging and a collision hazard exists.
    b. Mechanical trouble exists of which the pilot might not be aware.
    c. Other hazardous conditions are present which call for intensified pilot or operator alertness. These conditions may include obstructions, soft field, ice on the runway, etc.

    So, if you see red/green, take your best guess.
     
    PeterNSteinmetz and denverpilot like this.
  13. Palmpilot

    Palmpilot Touchdown! Greaser!

    Joined:
    Apr 1, 2007
    Messages:
    17,309
    Location:
    PUDBY
    Display Name:

    Display name:
    Richard Palm
    One hypothetical I thought of is flooding or other contamination on a portion of the runway. Or maybe the runway is just wet and braking action has been reported as poor.
     
  14. WannFly

    WannFly Final Approach

    Joined:
    Nov 28, 2016
    Messages:
    5,198
    Location:
    KFAR
    Display Name:

    Display name:
    Priyo
    how about things like "Caution wake turbulence" or "Caution, lots of bird activity around the airport". of course when your radio is down, you cant hear any of them.. so the red and green comes to the rescue (pun intended)
     
  15. Matthew

    Matthew Touchdown! Greaser!

    Joined:
    Apr 18, 2005
    Messages:
    16,277
    Location:
    kojc, kixd, k34
    Display Name:

    Display name:
    Matthew
    I've never "had" to use signals, but I've always wondered if a red/green might make a go-around a good idea. If it's solid green the next time around then OK, and if it's still flashing you might have had a chance to see a reason for it.
     
  16. WannFly

    WannFly Final Approach

    Joined:
    Nov 28, 2016
    Messages:
    5,198
    Location:
    KFAR
    Display Name:

    Display name:
    Priyo
    a go around in a busy controlled environment when you are not talking and Tower doesnt know your intentions can pose some different set of problems ... for them mostly. would they divert arriving big irons and others in the pattern? would they hold the departing traffic? lots of unknowns.

    love to hear from some of our ATC people. @Timbeck2
     
  17. Matthew

    Matthew Touchdown! Greaser!

    Joined:
    Apr 18, 2005
    Messages:
    16,277
    Location:
    kojc, kixd, k34
    Display Name:

    Display name:
    Matthew
    Sure, you need situational awareness. You'd have to be ready for that red light in your scenario, go somewhere else and sort it out.
     
  18. wsuffa

    wsuffa Touchdown! Greaser!

    Joined:
    Feb 22, 2005
    Messages:
    22,546
    Location:
    DC Suburbs
    Display Name:

    Display name:
    Bill S.
    In other words, "good luck, we're all counting on you"
     
    Jim K, bflynn and Matthew like this.
  19. Sinistar

    Sinistar En-Route

    Joined:
    Sep 9, 2016
    Messages:
    2,814
    Display Name:

    Display name:
    Brad
    Zombies.
     
    PeterNSteinmetz and WannFly like this.
  20. Matthew

    Matthew Touchdown! Greaser!

    Joined:
    Apr 18, 2005
    Messages:
    16,277
    Location:
    kojc, kixd, k34
    Display Name:

    Display name:
    Matthew
    Heh - that's the signal that you will have an audience!
     
    bflynn and wsuffa like this.
  21. denverpilot

    denverpilot Tied Down

    Joined:
    Nov 8, 2009
    Messages:
    52,658
    Location:
    Denver, CO
    Display Name:

    Display name:
    DenverPilot
    “There’s a coyote next to the runway...” :)
     
  22. jsstevens

    jsstevens Final Approach PoA Supporter

    Joined:
    May 18, 2007
    Messages:
    5,337
    Display Name:

    Display name:
    jsstevens
    I thought the light signal for that was the muzzle flash of the rifle...
     
    denverpilot likes this.
  23. Larry in TN

    Larry in TN Cleared for Takeoff

    Joined:
    Nov 16, 2013
    Messages:
    1,463
    Location:
    Nashville, TN
    Display Name:

    Display name:
    Larry in TN
    In the late 1980s, I had a radio failure in the pattern in a C-152 while teaching a primary student.

    It was a very busy pattern with a lot of training aircraft--probably eight to ten aircraft on frequency. The airport hosted a university flight program as well as three additional, busy, flight schools. We were flying closed traffic patterns and the radio failed about the time we turned downwind but before we had been given our sequence for the next landing.

    The student was a business owner who had a habit of learning the information that he thought important and ignore information that he deemed unimportant. Since radios are 100% reliable, light gun signals had, of course, been deemed unimportant.

    Before the radio failed, I had heard an inbound aircraft call who had been given instructions to enter a right-base. We were on right-downwind. I walked the student through figuring out a best guess at our sequence from what we knew of the traffic in the area. We picked out the right-base traffic and adjusted to follow him as he followed the aircraft that had been in front of us on downwind. On final, we received the light signal for 'cleared to land'.

    After clearing the runway, we turned toward the tower (behind us) to get our 'cleared to taxi' light signal. Our taxi route required crossing a runway so, as we approached, I had the student angle toward the tower, just in case something had changed, and we saw another 'cleared to taxi' signal.

    When that student showed up for his next lesson, he was very anxious for me to test him so he could show off his newly-acquired light signal knowledge. LOL

    After that experience, I started giving my pre-solo students a light gun demonstration before they soloed.
     
    denverpilot likes this.
  24. Matthew

    Matthew Touchdown! Greaser!

    Joined:
    Apr 18, 2005
    Messages:
    16,277
    Location:
    kojc, kixd, k34
    Display Name:

    Display name:
    Matthew
    One of my CFIs, it was probably on a flight review, had me do at last one landing with light signals. In that case, I was told to remove my headset so I couldn't hear the radio traffic. CFI and tower were talking so they could verify clearances just in case, but I had to go strictly by the light signals because I couldn't hear their conversation.

    The only time I thought I'd need the light gun for real was when I was solo on a very rough day. I can't remember if this was before or after my checkride, but I do remember I was alone in the plane. I had gone to an untowered airport for some pattern work and on the way back I couldn't contact tower. It turns out the day was so bumpy that when I had switched to the tower freq I had inadvertently bumped the volume knob down very low. I did my normal radio call from about 10 out and didn't get a response, I called again when I was a little closer and didn't hear anything, and I tried again. I was starting to think I'd have to make a decision pretty soon because I was getting closer to that D-space. I tried to troubleshoot a few things and then had that "uhh, yeah, that's it" moment and turned up the volume. Tower seemed pretty happy to have me answer back, so it was all good. I had two radios in that plane, I can't remember if I had thought about trying #2 or not.
     
  25. Timbeck2

    Timbeck2 Final Approach

    Joined:
    Nov 4, 2015
    Messages:
    7,109
    Location:
    Vail, Arizona
    Display Name:

    Display name:
    Timbeck2
    There are rare instances where we don't already know of a radio failure before they get to the pattern. Only a couple of times has there been one right after take off during my career. As you know, alternating red and green means to use caution. One example is clearing someone to land (helicopter) on a non-movement area because we can't control the maintenance vehicles, fuel trucks, and other assorted stuff. Also the use of a light gun is pretty common during exercises which employ radio silence.
     
    denverpilot and WannFly like this.
  26. gkainz

    gkainz Final Approach

    Joined:
    Feb 23, 2005
    Messages:
    8,171
    Location:
    Arvada, CO
    Display Name:

    Display name:
    Greg Kainz
    I thought flashing RED GREEN RED GREEN meant STOP! GO! STOP! GO! :D
     
    denverpilot and WannFly like this.
  27. denverpilot

    denverpilot Tied Down

    Joined:
    Nov 8, 2009
    Messages:
    52,658
    Location:
    Denver, CO
    Display Name:

    Display name:
    DenverPilot
    You’re an evil genius. You know that, right? :)
     
    gkainz likes this.
  28. IK04

    IK04 Pattern Altitude

    Joined:
    Nov 6, 2018
    Messages:
    1,930
    Location:
    Copperas Cove, Texas
    Display Name:

    Display name:
    LNXGUY
    After a complete electrical failure while IMC at night, I returned to my home airport and received light gun signals from the tower. They knew I was coming.

    After the usual green lights for landing and taxi, they gave me the green/red for a few seconds as I taxied in.

    I assumed it meant "Good luck; you're on your own."
     
  29. wsuffa

    wsuffa Touchdown! Greaser!

    Joined:
    Feb 22, 2005
    Messages:
    22,546
    Location:
    DC Suburbs
    Display Name:

    Display name:
    Bill S.
    Call the caterers
     
    denverpilot likes this.
  30. WannFly

    WannFly Final Approach

    Joined:
    Nov 28, 2016
    Messages:
    5,198
    Location:
    KFAR
    Display Name:

    Display name:
    Priyo
    If this is Charlie airspace this means go ahead and land, the FAA is going to chew your azz
     
  31. ahypnoz

    ahypnoz Pre-takeoff checklist

    Joined:
    Feb 22, 2015
    Messages:
    129
    Location:
    oklahoma city
    Display Name:

    Display name:
    ahypnoz
    The FAA should require a light signal at the runway threshold of every controlled airfield. Like a vasi “trafic light“. Steady green, cleared to land, steady red, not cleared to land and continue circling. (It would be manually controlled by the tower). It would also be used with every landing. Redundant safety.
     
  32. FastEddieB

    FastEddieB Final Approach

    Joined:
    Oct 14, 2013
    Messages:
    9,549
    Location:
    Lenoir City, TN/Mineral Bluff, GA
    Display Name:

    Display name:
    Fast Eddie B
    I’m red/green deficient “color blind”, so I needed to get a “Statement Of Demonstrated Ability” to get my Medical back in 1975. For that, I went up with someone from the Miami GADO and they had the Opa Locka Tower shoot me signals, which I could clearly identify. The red was obvious. I could differentiate the green from the white, but for me the green does look pretty washed out. Same thing with green traffic lights - they’re “greenish” to me, but don’t radically differ from white street lights.
     
  33. FastEddieB

    FastEddieB Final Approach

    Joined:
    Oct 14, 2013
    Messages:
    9,549
    Location:
    Lenoir City, TN/Mineral Bluff, GA
    Display Name:

    Display name:
    Fast Eddie B
    Reminds me of a Stephen Wright bit. He named his dog Stay. Why? Because he enjoyed the confused look he got when he called him: “Here, Stay. Here, Stay”.
     
    MuseChaser and denverpilot like this.
  34. Ravioli

    Ravioli Final Approach PoA Supporter

    Joined:
    Dec 1, 2014
    Messages:
    7,205
    Location:
    Fort Worth
    Display Name:

    Display name:
    Pasta Man
    I've had to use them once, on my first solo XC. The alternator failed and I was NORDO. I called the tower from a nearby non-towered field using my mobile phone and told them I'd be coming. They reviewed the procedure and the signals with me, and then I went. I was so scared I don't know if I noticed the colors. Was just thinking "not red, not red"
     
    denverpilot and WannFly like this.
  35. luvflyin

    luvflyin Final Approach

    Joined:
    May 8, 2015
    Messages:
    7,678
    Location:
    Vancouver, WA
    Display Name:

    Display name:
    Luvflyin
    Controllers would boo boo that about as often as the boo boo verbally
     
  36. Larry in TN

    Larry in TN Cleared for Takeoff

    Joined:
    Nov 16, 2013
    Messages:
    1,463
    Location:
    Nashville, TN
    Display Name:

    Display name:
    Larry in TN
    In the late 1980s I was flight instructing at a busy towered field. My flight school had a private pilot ground school and my wife signed up.

    The class took a field trip to the tower and one of the controllers demonstrated the light gun for them. Someone asked a question about the different signals and the controller told them, "Green means do whatever you want, Red means go away!"

    I guess he thought he was helping but all he did was create a class of future pilots who would never learn the light gun signal chart!
     
  37. Robert S.

    Robert S. Filing Flight Plan

    Joined:
    Saturday
    Messages:
    8
    Display Name:

    Display name:
    Robslv1
    Thank you all for the Information on this topic,
    I understand the color light produces, flash lights, but hope to never have to use them.

    I wonder how offon ATC has to do it tho.
     
  38. PaulS

    PaulS Final Approach

    Joined:
    May 29, 2007
    Messages:
    9,570
    Display Name:

    Display name:
    PaulS
    I had a radio issue once approaching a delta. I got flashing red, and thought to myself, WTF do I do now? So I turned away, fiddled with the radio again, and it worked, they cleared me in and cleared me to land. I had no trouble seeing the light.