What I noticed during this thread is that most aircraft seem to have more switches for lights than the Aquila I’ve flown so far, which has only “ACL” (anti-collision light), landing light and position light switches. The ACL combines wing-tip strobes+beacon, so there was no way to differentiate between these.
I was taught:
The “beacon on” is a reminder that the master switch is on. Helped me a few times when I got out of the airplane (magnetos off), but the beacon was still on…
172driver wrote:
I disagree. Your example is about an observer looking UP into the sky from the ground. That’s very, very different from looking DOWN against background clutter to spot an airplane. Seeing small airplanes against the background clutter of a big city (L.A. in my case) or patchwork fields is a challenge to say the least. Keeping the landing light on during the day definitely helps.
Your welcome to disagree, but think about this. If you are descending onto an aircraft which is below you, it will depend on the direction of the other aircraft. If you are both going the same way, your landing light and the target below will do neither any good. Unfortunately when approaching an airport, aircraft tend to use similar patterns and are going the same way. Think, faster low wing aircraft descending onto slower high wing aircraft from behind.
If you are going opposite directions, the other aircraft will have to be well below the horizon in order to present a contrast with the background. Remember when airborne, the horizon is below your altitude, curvature of the earth and all that stuff. Mountains help because they can be above the horizon and are dark. Anyway this was studied along with use of strobes and found not to improve the ability of aircraft to be spotted. If the aircraft is low enough to have a dark background, they are no threat unless they are climbing into you, and in that case their landing light can help.
On a bright day, even aircraft below you will be extremely difficult to spot and you will see the airplane before you can determine if the landing light is on. During night, dusk, and an overcast or low visibility, the landing light can be seen and is a great aid, but in the bright of the day it is not much help and may hurt. The really pernicious thing is that aircraft on a collision course don’t move against the background and the eye is good at detecting motion against the background.
The flashing mode can be turned on and off. I am not sure how exactly – whether it is a switch or whether it works like most LED torches i.e. you press the on/off switch a couple of times rapidly.
In my plane the beacon and strobes are on one switch. They go on before engine start.
Landing light is on whenever the plane moves. Nav lights at night only.
I believe:
Flashing = anti collision light by definition (cs23 specifies all the frequency of flash etc)
Landing and taxi lamps are primarily there to illuminate the path ahead in poor vis / night so I would think an engineer couldn’t sign off such an installation / mod as it wouldn’t meet that requirement unless it was switchable between flashing and fully on/off
Peter wrote:
Some say flashing lights are illegal…
that should depend on the flashing.
If it is stroboscopic, maybe.
But if it is a wig wag, I would be surprised, as some manufacturers propose it from the factory (TBM’s got the option, and southwest airlines aircraft used (and maybe still use) this too).
NCYankee wrote:
Landing lights during the bright sky make the aircraft less visible, not more visible. In WWII, this was used as a stealth method, light up the entire airplane leading edge and it would make attack aircraft harder to see by submarines and the attack aircraft could get closer before being spotted.
I disagree. Your example is about an observer looking UP into the sky from the ground. That’s very, very different from looking DOWN against background clutter to spot an airplane. Seeing small airplanes against the background clutter of a big city (L.A. in my case) or patchwork fields is a challenge to say the least. Keeping the landing light on during the day definitely helps.
I leave my landing and taxi lights on when flying at low level (both are LED ones) and the strobes are on all the time too when the engine is running. However this is for daytime which is the vast majority of my flying and IMHO there is little risk of “blinding” anyone in daylight. At night it is good form to not use strobes when off a runway.
We had some threads here on the flashing landing/taxi lamps which is one of the installation options on most of the LED products. It requires running a wire between the two wingtips to sync the lights. Some say flashing lights are illegal… but it sure as hell would make the plane a lot more visible.
Maoraigh wrote:
In bright day, I’ll see an aircraft before I see its strobes or beacon. Landing/taxi light I’ll spot much sooner.
In dim light, the strobes are eye-catching.
I agree.
Landing lights during the bright sky make the aircraft less visible, not more visible. In WWII, this was used as a stealth method, light up the entire airplane leading edge and it would make attack aircraft harder to see by submarines and the attack aircraft could get closer before being spotted.
