Page 3 of 3 FirstFirst 123
Results 21 to 28 of 28

Thread: taxi and landing light focal point distances

  1. #21
    Flyfalcons's Avatar
    Join Date
    Feb 2012
    Location
    Bonney Lake, WA
    Posts
    197
    Quote Originally Posted by FlyingRon View Post
    If you aim your approach at the numbers, you're never going to use the full length of the runway.
    Do not assume that the angle of the aircraft on approach equals the glide slope. I can almost assure you that you are at a positive angle of attack.
    Flying at night into an unfamiliar airport, I'd rather be on the proper glidepath (aiming even further down the runway) and have obstacle clearance assured than worry about dropping the wheels right on the numbers.
    Last edited by Flyfalcons; 01-19-2013 at 01:13 PM.
    Ryan Winslow
    EAA 525529
    Stinson 108-1 "Big Red", RV-7 under construction

  2. #22

    Join Date
    Oct 2011
    Location
    New Hampshire
    Posts
    1,342
    The statement "By convention the pitch angle is the angle between the longitudinal axis of a fuselage and the horizontal plane. Usually a pitch angle is of an airplane, rather than a wing." doesn't apply in my world. We look at the angle of attack of the wing, its angle of incidence with the fuselage, and then the glide path and where on the runway the glidepath takes us. The horizontal plane is irrelevant and reference to it possibly misleading.

    And the statement "I'd rather be on the proper glidepath" is missing information. That glide path is different for a C-150 vs a DHC-6, or a Pitts and additionally depends on the type of operation. I will suggest that any pilot who thinks that there is a one size fits all answer needs broader experience.

    After 21 posts, I hope that when the original poster gets the light installed and test flown, he reports what the final answer was.

    Best of luck,

    Wes
    N78PS

  3. #23
    Flyfalcons's Avatar
    Join Date
    Feb 2012
    Location
    Bonney Lake, WA
    Posts
    197
    Not really, each runway with visual glidepath lighting has just one glide path, and going below it at night can be hazardous to your health no matter what airplane you're in.
    Ryan Winslow
    EAA 525529
    Stinson 108-1 "Big Red", RV-7 under construction

  4. #24

    Join Date
    Oct 2011
    Location
    New Hampshire
    Posts
    1,342
    Well, other folks experience may be different, but unless I am flying the ILS, I can report that a power off, full flap, approach in the C-150, C-172, C-180, C-182, C-205, C-206, C-207, C-208, C-310, PA-28R, King Air, DHC-6, and a bunch of other airplanes all use different glide paths day or night. There is certainly a minimum glide path that keeps you out of the obstacles, but most of us fly a steeper glide path depending on the runway, the aircraft, and how it is configured. And I live on an airport where flying a 3 degree glide path WILL put you in the trees. 4 degrees is the minimum.

    Best of luck,

    Wes
    N78PS

  5. #25
    Flyfalcons's Avatar
    Join Date
    Feb 2012
    Location
    Bonney Lake, WA
    Posts
    197
    Understood Wes, that different airplanes glide differently with the power at idle. That has little to do with obstacle clearance at night, where aiming for the runway numbers, instead of the touchdown zone, takes away the safety net of the visual (or instrument) glide slope. That last little bit of ducking below the visual or instrument path to "make the numbers" probably isn't the best idea at an unfamiliar airport at night. If you really want me to list the types I've flown to impress you then I guess I could, but like I said earlier, trees and power lines don't really care what you're in.
    Ryan Winslow
    EAA 525529
    Stinson 108-1 "Big Red", RV-7 under construction

  6. #26

    Join Date
    Oct 2011
    Location
    New Hampshire
    Posts
    1,342
    I just realized that reading post #23 that you are talking about big airports with VASI or PAPI. I operate out of little airports that do not have those conveniences. Working in and out of 1900' you do not have extra runway to waste, day or night. You try to fly the same pattern and final day and night for consistency that helps you see if you are going low on the planned profile. A tip - if the runway end lights look like they are flickering, there are trees between you and them.

    Folks have different experiences and in aviation it is unwise to assume that the rules of thumb for your environment work everywhere else.

    Thanks,

    Wes
    N78PS

  7. #27
    Flyfalcons's Avatar
    Join Date
    Feb 2012
    Location
    Bonney Lake, WA
    Posts
    197
    Wes, I think you'd find I have very similar experience background to you, based on the aircraft types you have listed as flown. As you have stated, if the runway lights are flickering, it means there is something between you and them. Unfortunately in a totally dark environment you have no idea exactly how far away that impediment is. It could be a mile away, or the flickering lights in front of you could be the last thing you see before suddenly hitting trees. In the case of going into runways at night with no visual approach path given, familiarity of the area is the only thing you have going for you. Notice the very important qualifier I have stated in my posts, unfamiliar airports. It's very important to understand the context of my statements. Aiming straight for the threshold at night at an unfamiliar airport is playing with fire. A very important part of my job is to fly to unfamiliar, mountainous airports at night, so I do have the experience to back up my assertions.
    Last edited by Flyfalcons; 01-19-2013 at 08:15 PM.
    Ryan Winslow
    EAA 525529
    Stinson 108-1 "Big Red", RV-7 under construction

  8. #28
    Cary's Avatar
    Join Date
    Aug 2011
    Location
    Fort Collins, CO
    Posts
    255
    I'd like to say this thread is generating more heat than light, but I won't say that. However, it does contain some issues which need clarifying.
    • How you aim the lights is as much a preference thing than an absolute. In other words, different strokes for different folks.
    • How you safely fly a night approach does not necessarily reflect how you will want your lights aimed. For instance, I said that I like the landing light to pick up the numbers before I begin to flare on final--that's not the same thing as saying that I like to land on the numbers at night, but that's how it was interpreted.
    • Really bright lights aren't very helpful unless they're aimed in such a way that they show what the pilot needs to see to safely land.
    • I've suggested to students and BFR clients in past years that staying a minimum of 400' AGL until in a position to land power off is a good idea for safety. When I aimed my landing light so that it lights up the numbers, I took that into account.
    • Someone said that you'll never use all the runway--but I can think of many runways I've landed on over the years which were short enough that I sure wouldn't want to touch down at the 1000' mark, leaving half the runway behind me.
    • Having PAPIs or VASIs or an ILS is wonderful, and it's a good idea to use them if they're there, for safety--but they aren't on every runway.

    Just some of my thoughts--but keep in mind that the only way to safely land at night is to practice landing at night. Everyone's thoughts here or elsewhere doesn't substitute for being properly trained and regularly practicing night landings.

    Cary
    "I have slipped the surly bonds of earth...,
    put out my hand and touched the face of God." J.G. Magee

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •