The enigma of aircraft lighting...

drgwentzel

drgwentzel

Pre-takeoff checklist
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The Enigma of Aircraft Lights


It is 12 noon, the 25 hour student pilot and I have just cleared the runway and they are completing the after landing checklist. They are at the part that says, “Lights ……As Required”.


I know what’s coming…I see them read it…they hesitate…I see the cognitive wheels revolving as they noodle through this seemingly innocuous declaration. They bring their tentative finger slowly over to the landing light switch; it hovers over the control for what seems an eternity. It’s almost as if they feel making the wrong choice will advance the Hobbs meter by 0.5. They next look at me confused and inquire, “Should I turn the landing light off?”


I always give them the answer and provide a rationale for why they should be turned off or left on. They will be even more confused if strobes are involved. The cruise checklist (which, by the way, doesn’t even mention strobes) simply states, “Landing and Taxi Lights…..Off” and will cause the student to reach over and reflexively turn off both the landing light and the strobes!


I reviewed this issue with another flight instructor. I asked him if he has the same situation come up, and if so, what he does about it. He explained, “I just ask them to answer 2 questions:”


1) do you need the lights to see?

Or

2) do you need the lights to be seen?”


These are easy and logical questions and I have been utilizing this approach when training my students, but with varying results. Therefore, let’s go over how we should utilize the lighting systems of our aircraft and why.


Aircraft certified with an electrical system and have installed lighting systems typically include all or some the following:


· Position lights (aka navigation or nav lights)

· Primary Anti-collision light (usually the beacon)

· Landing / Taxi lights

· Strobes (usually supplementary anti-collision lighting)


Some of these lights and their use are regulated by the FAA; others systems are operated by either common sense or personal preference. Ok, let’s get started…


1. Position lights: these are required by regulation to be used while operating on the ground or in the air after sunset and left on until engine shutdown or up to sunrise. Therefore, during the day they are OFF.


2. Primary Anti-collision light, such as the beacon, are required to be used during all types of operations (day or night). If the master switch is on, so is the beacon. Closer to the truth, the beacon light switch is ON, period! End of story! Barring a small beacon electrical fire, DON’T TOUCH IT! Personally, the beacon shouldn’t even have a switch; it should only have a circuit breaker that can be pulled, but I digress.


3. Landing / Taxi lights: This is where there is some confusion and personal preference.

a. First, if an aircraft has both a landing and taxi light, consider them one light and one switch. They are either both on or they are both off. There is rarely a need to have one on and the other off.

b. My advice is that EVERY take-off and EVERY landing has both landing and taxi lights on (day or night). At night we need them TO SEE and TO BE SEEN and during the day we need them TO BE SEEN.

c. After landing, if it is daytime, turn them off. We don’t need them TO SEE and we don’t need them TO BE SEEN.

d. After landing, if it is nighttime, leave them on. We need them TO SEE and we need them TO BE SEEN. Turn them off ONLY if they might cause a distraction to another pilot, especially if they are taking-off or landing.

e. There is a regulation to have a landing light, but that is only for aircraft utilized at night for commercial operations.

f. In cruise flight there is some personal preference that can be afforded.

i. Some pilots always turn them off and others leave them on.

ii. There is a recommendation from the FAA to leave landing lights on below 10,000 feet, but this does not appear to be universally adopted or practiced in general aviation.

iii. Since the advent of LED lighting many pilots choose to just leave them on (day or night). These lights use less power, produces less heat, provides more light, and they last for 10’s of thousands of hours, so the attitude is, “What the heck, just leave them on TO BE SEEN.”

4. Strobes:

a. Strobes are another form of anti-collision light and usually supplementary to a beacon.

b. They should be turned on prior to entering a runway for any reason and left on until completely clear of a runway TO BE SEEN, day or night.

c. They should be turned on prior to take-off TO BE SEEN.

d. They should be left on in cruise flight TO BE SEEN…

i. …but, they should be turned off in flight if determined by the PIC that they constitute a hazard to safety due to adverse meteorological conditions. (14 CFR Section 91.209).

e. They should be turned off after landing and clear of the runway so not to distract other pilots or ground personnel.

I hope this helps illuminate the uses of aircraft lighting in the different phases of ground and air operations. If you have any questions, discuss it with any flight instructor.


Gene Wentzel, ATP, CFII
 
During taxi, however, many pilots use taxi lights to indicate that they're moving, and turn them off to indicate that they're not moving (holding short of a runway, for example).
 
I made a simple list for me:

1. Nav lights stays on all the time, day / night, the dimmer switch is on a permanent ON position
2. Recognition lights (end of both wings) and Beacon comes on after engine start until shutdown (I am VFR only, at night I might turn the recognition lights off if I am taxing back and there is another AC taking off / landing)
3. Landing lights and Strobes as I enter runway, stays on until I land and exit the runway

I will occasionally turn the landing light on when taxiing if I see another AC around to tell him that I am about to move
 
I chuckled at the “hesitation” part. Anytime a checklist has a decision to make someone new is going to do that.

Pretty good article. The “moving vs not moving” taxi light is pretty common. Especially when trying to not blind ground crew and other aircraft. And I never trust other airplanes to do it anyway, but I do it. I could see not confusing a student with it, but it can also just be added to the taxi checklist top and bottom, and I’ve seen that done as well. I’ve done that to my personal airplane’s checklist.

Nose gear mounted taxi lights on big retracts are also a problem here. Yeah, you can “be seen” but you’ve destroyed the line guy or gal’s night vision so they can’t do the other part of their job, watching your wingtips with you at night. But you’re “seen”! LOL.

The other one that was hand-waved away a bit was aircraft where the strobes are the primary anti-collision lights. That requires a different technique.

And then there’s the airplanes that are bulb-blow-o-matics like mine was prior to switching the cowl mounted taxi and landing lights to LED. That was an exercise in frustration if you “over used” them. My decision making shouldn’t have changed much for the “be seen” question but it did when you knew you’d be cussing and changing an FAA approved tractor bulb you could get at Tractor Supply for a tenth the price, every few flights.

So yeah. Good article for beginners. Can become more nuanced as the pilot doesn’t have a full brain interrupt firing and halting all processor activity every time they read a decision point on a checklist. :)
 
For me

Position and beacon are always on

Taxi on when I'm moving on the ground, NO STROBES

All lights on and transponder to alt if I enter a runway

Prior to takeoff taxi, landing, recog, strobes

After 1000' taxi and landings off (if they are part of the landing gear)

When I drop the gear, taxi, landing and recogs on

Clear the runway, just position beacon (always on) and taxi.

-as required- depending on the conditions, in IMC I often turn the strobes off so the light isn't bouncing in the plane, sometimes I'll shoot a approach without landing or taxi or recogs if it improves my forward visibility in IMC / snow.

I'll also run my landing and recogs during taxi if I'm at a airport in poor condition or I'm concerned about deer or something.

Sometimes flash my strobes (in my best Sean Connery voice, "one ping only please") if I need to get the attention of someone on the ground.



Lights are much like radio work, don't worry about being 100% by the book or put crazy amounts thought into it, just use common sense and you'll be fine.
 
I need to work on this too. In ground school, I had to make up a drawing so I could understand which lights were which (I think some use more than one designation for the same type of lights) because there was no one universal description/drawing for all lights.

But there was one, I believe the beacon, that we were taught should be turned on prior to starting the engine, as an extra warning (and after really checking no one is nearby and yelling contact) that the prop was going to be turning.

Thanks to the OP for bringing this up and explaining more of the concepts, and to the others who added to it.
 
LongRoadBob said:
But there was one, I believe the beacon, that we were taught should be turned on prior to starting the engine, as an extra warning (and after really checking no one is nearby and yelling contact) that the prop was going to be turning.
Click to expand...

Correct. On most (not all) aircraft your “aviation red” or white rotating or flashing beacon is your official “anti-collision light”. Think of it as a blinking four way stop light. It tells anyone approaching the aircraft to stop! There’s probably an invisible to the eye prop turning and the aircraft is going to move. Stay away. This one is on from startup to shutdown. (Falls into the OPs “need to be seen” rule.)

Next up, your position or navigation lights. These are the same lights you’ll see on a boat. We are silly navigators of the skies instead of the waterways. They indicate to other “sailors” which side of the aircraft they’re viewing at night when they can’t see your “hull”. (Aviation insurance includes a “hull” value too! It’s just a boat in the sky!) Our right-of-way rules are nearly identical to boats and ships as well. And at night, boats use these lights to know on which side to legally and safely pass, overtake, etc. These are the red light that doesn’t blink on your left (port) wingtip, green light on your right (starboard) wingtip, and the white light on your tail (aft). These are on at night for obvious reasons and usually aren’t bright enough to be useful at all to “passing ships” in daytime. (The OP’s “need to be seen rule”.)

Those are the basic ones.

Then some crazy aviators decided that landing on dark runways at night without a whole bunch of buddies with cars and trucks with headlights parked around the runway was probably going to lead to a crash and it would hurt, they added a landing light to their craft. This is just a forward bright white light so you can see. A big old headlight. Similarly someone figured out that angling the headlight down a bit and focusing it with a lens made for a pretty good light for seeing runways when on a final approach, but a poor light for seeing a wide swath of the runway once they landed.

So they changed the lens and the taxi light was born. Now they could see to taxi. Yay! Now they wouldn’t be as prone to running into other objects on the ground after using that landing light to land in the dark.

Some smart folks also realized that in high traffic areas, leaving one or both of those on sure made an airplane coming right at you a LOT more visible in day and night conditions, so aviators started using them for collision avoidance.

(Both of those lights fall into both categories of the OPs questions depending on the operation being flown. Landing or taxiing at night? “Need to see!” Flying in densely trafficked airspace? “Need to be seen.” So you use them as appropriate for both.)

And finally newer technology came along and some enterprising engineer created the strobe. Basically a powerful flashbulb that could pop out a whole bunch of bright white light for a brief moment from a high voltage discharge and then a big capacitor had to be charged up again to do it again. Pop, pop, pop. These were found to increase visibility of airplanes both day and night in the air by even more than the existing lights above, so they were added to airplanes that have them, on each wingtip.

(These fall into “need to be seen” and can be used anytime for that. They tend toward being too bright to use in close proximity to other pilot’s eyes and cockpits on the ramp so we turn them off to keep from flash blinding them.)

That’s about it. But there’s a re-hash of the common ones.

Now on SOME airplanes, the manufacturer convinced the FAA that the strobes could act as anti-collision lights instead of the red or white flashing beacon. FAA agreed and airplanes with strobes and no beacon will operate the strobes continuously from startup to shutdown unless doing so create a hazard for other pilots and airplanes.

A friend of mine tells a funny story from long ago when he flew the same high wing turboprop airliner that @mscard88 flew ... ATR.

He’s a captain and there’s all sorts of delays on the ground tonight getting to the runway. The ATRs he flew had white rotating/flashing beacons instead of red ones, and as we see above, those are on from startup to shutdown.

We also know from above it’s bad form to run your strobes on the ground and blind people with them.

A larger (along with a larger ego, perhaps) aircraft’s pilot called ground control in a grumpy mood, bad weather, ground delays, and didn’t realize the white lights flashing at him from the “little turboprop” were anti-collision lights. The radio calls went like this...

SnarkyBigAirliner: “Ground, could you tell the pilots it’s unprofessional to have their strobes on?”

CommuterATRFirstOfficer: “Ground, tell the SnarkyBigAirliner, those aren’t strobes... THESE are STROBES!”

As he punched the button to blast the cockpit of SnarkyBigAirliner with a full blast from his high wing strobes with his wingtip sticking right out at the cockpit level of SnarkyBigAirliner, the way everyone was parked waiting to move.

Friend said his FO did it so fast he couldn’t stop him but he was laughing too hard after that to breathe. The FO had already tuned them back off before he could come up for air.

And... Not another word was heard from the folks flying SnarkyBigAirliner complaining about the professionalism of CommuterATR that night. And everyone made it to the departure runway and whoever got blasted in SnarkyBigAirliner’s cockpit probably had their night vision back by then.

Names of airlines, pilots, and location reserved to protect the innocent ... or cover for the guilty as the case may be.
 
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