Hi,

I’ve had a question lingering in my head since I was 8 years old and saw planes at night.

Why do some planes have a blinking beacon light (<.1 sec flash) and others have a steady on and off (>.5 sec flash. For example, look at a short video of an A321 beacon: https://youtube.com/shorts/Igtk8WaCoKU?feature=share
vs
E75L beacon: https://youtube.com/shorts/1zxn5Us5DD4?feature=share

I know some people may not be able to tell, but I’d appreciate an answer.

So far I’ve seen the blinking beacon on:
- A320 and A320N family
- A350
- A330-2/300 AND -8/900
- A380
- B737 classic & NG
- B747-400 & -8
- B757
- B767
- B777-2/300
- All CRJs
- E75S

And the longer blink with:
- A220
- 737 MAX
- B777x
- B787
- E135/40/45 family
- E75L

Is it just more advanced lights? If so, why is there a need for the flash to be longer? It appears to be in the newer aircraft, and almost none of Airbus’ aircraft.

Thanks for the help,
Jake

Led vs. strobe light. The strobes flash as the capacitors in the light discharge. Very bright but a short duration. The led's have a driver that controls the length of time the led is on. The slightly longer duration is more visible while still having the strobe effect.

Jacobrhassell wrote:

Is it just more advanced lights? If so, why is there a need for the flash to be longer?
Jake

As atlamt said, the longer flash is the newer LED light, which is more advanced. There is a need for the LED flash to be longer. The older flashlamps (strobe) lights as atlamt said, discharge a large amount of energy instantaneously, creating an extremely intense burst of light. So intense, that if the amount of light emitted from the burst were continuous, it would be blinding (well, not literally), but its extremely short duration has the intended effect of high visibility.

An LED beacon by contrast doesn't operate with sudden capacitive discharge. Its brightness (which can certainly be quite high), needs more "on time" to have the achieve a similar level to that of a flashlamp.

rjsampson wrote:

Jacobrhassell wrote:

Is it just more advanced lights? If so, why is there a need for the flash to be longer?
Jake

As atlamt said, the longer flash is the newer LED light, which is more advanced. There is a need for the LED flash to be longer. The older flashlamps (strobe) lights as atlamt said, discharge a large amount of energy instantaneously, creating an extremely intense burst of light. So intense, that if the amount of light emitted from the burst were continuous, it would be blinding (well, not literally), but its extremely short duration has the intended effect of high visibility.

An LED beacon by contrast doesn't operate with sudden capacitive discharge. Its brightness (which can certainly be quite high), needs more "on time" to have the achieve a similar level to that of a flashlamp.

So why does Airbus refuse to implement this advanced light? Even on the new A350 and A330-900, it’s still the “strobe” light.

Thanks for the help!

Hello,

I’ve noticed that on some E145s, the beacon light pattern is: Bottom, Top, Strobe, Bottom, Top, Strobe. However, some others I’ve seen (Even for the SAME airline!), the lights go BOTH, Strobe, BOTH, Strobe.

Why are there 2 different patterns for the same aircraft in the same airline?

Jacobrhassell wrote:

rjsampson wrote:

Jacobrhassell wrote:

Is it just more advanced lights? If so, why is there a need for the flash to be longer?
Jake

As atlamt said, the longer flash is the newer LED light, which is more advanced. There is a need for the LED flash to be longer. The older flashlamps (strobe) lights as atlamt said, discharge a large amount of energy instantaneously, creating an extremely intense burst of light. So intense, that if the amount of light emitted from the burst were continuous, it would be blinding (well, not literally), but its extremely short duration has the intended effect of high visibility.

An LED beacon by contrast doesn't operate with sudden capacitive discharge. Its brightness (which can certainly be quite high), needs more "on time" to have the achieve a similar level to that of a flashlamp.

So why does Airbus refuse to implement this advanced light? Even on the new A350 and A330-900, it’s still the “strobe” light.

Thanks for the help!

I don't think it is a questions of "refusing".

There are probably multiple reasons involving costs and tooling.

Jacobrhassell wrote:

rjsampson wrote:

Jacobrhassell wrote:

Is it just more advanced lights? If so, why is there a need for the flash to be longer?
Jake

As atlamt said, the longer flash is the newer LED light, which is more advanced. There is a need for the LED flash to be longer. The older flashlamps (strobe) lights as atlamt said, discharge a large amount of energy instantaneously, creating an extremely intense burst of light. So intense, that if the amount of light emitted from the burst were continuous, it would be blinding (well, not literally), but its extremely short duration has the intended effect of high visibility.

An LED beacon by contrast doesn't operate with sudden capacitive discharge. Its brightness (which can certainly be quite high), needs more "on time" to have the achieve a similar level to that of a flashlamp.

So why does Airbus refuse to implement this advanced light? Even on the new A350 and A330-900, it’s still the “strobe” light.

Thanks for the help!

I could be wrong but if I were to guess I bet it’s a customer option.

Starlionblue wrote:

Jacobrhassell wrote:

So why does Airbus refuse to implement this advanced light? Even on the new A350 and A330-900, it’s still the “strobe” light.

I don't think it is a questions of "refusing".

There are probably multiple reasons involving costs and tooling.

Not to mention you can’t just decide to change a part of a certified design without at least some additional certification effort.

These were all rotating flashing lights back in the old days, right?

Here’s how to kick it old skool.

Jacobrhassell wrote:

So why does Airbus refuse to implement this advanced light? Even on the new A350 and A330-900, it’s still the “strobe” light.

Thanks for the help!

A picture is worth a 1000 words, Nuff said

IFlyVeryLittle wrote:

These were all rotating flashing lights back in the old days, right?

Certainly many.. but flashlamps ("strobes") go well back into the old days as well.

Jacobrhassell wrote:

So why does Airbus refuse to implement this advanced light? Even on the new A350 and A330-900, it’s still the “strobe” light.

Thanks for the help!

Airbus still uses LED's, they just choose to program theirs with a fast flash pattern. Any A320/321 with sharklets has LED wing tip strobes, same with the 350. Boeing just chooses to use a slower pulse type flash pattern.

Jacobrhassell wrote:

Hello,

I’ve noticed that on some E145s, the beacon light pattern is: Bottom, Top, Strobe, Bottom, Top, Strobe. However, some others I’ve seen (Even for the SAME airline!), the lights go BOTH, Strobe, BOTH, Strobe.

Why are there 2 different patterns for the same aircraft in the same airline?

In my experience the E145 flashes totally randomly. The lights aren't synched so when they are all switched on, they appear to flash at the same time, but slowly fall out of sync. What I've seen for the E145 at some airlines is that the beacons are being replaced by LED's as they burn out. So you will have an aircraft with the top beacon as a strobe, and the bottom beacon as LED. The CRJ series has a distinct top bottom flash for the red beacon.

Airbus has the most distinct and consistent flash pattern. The top and bottom strobe are synched, as well as the wing and tail strobes. The red beacons will flash at the same time. When the white wing and tail strobes are turned on, they will flash opposite the beacons, so you'll always see Red, White, Red, White on an Airbus. Additionally the wingtip strobes will flash twice, while the tail strobe flashes once. I'm not sure how accurate this is, but I was told its supposed to be easier to determine if an aircraft is facing towards or away from you at a greater distance then the nav lights are visible. the MD-11 had the same pattern. Exception to the rule is the A220, which was designed by Bombardier. Quirk to this aircraft is that the weight on wheels sensor changes the brightness of the red beacon. When the aircraft takes off, the beacon gets brighter.

kalvado wrote:

I am not sure if Collins is the sole supplier of those lights for Airbus, but they have some interesting brochures.
At least for A350 Collins doesn't offer any strobes in their brochure:
https://www.collinsaerospace.com/-/medi ... 825e869998

A350 strobe lights (and almost all the other exterior lights) are supplied by Safran.
First MSN were fitted with HID technology then LED was introduced (around MSN 300), both technologies are not interchangeable.

Thanks for everyone’s help!

IFlyVeryLittle wrote:

These were all rotating flashing lights back in the old days, right?

The requirement for anti-collision beacons was promulgated in August, 1971. Lots of military planes didn’t get them for a few years on. The F-100 had beacons installed as they went thru depot work. If you were flying one with a beacon, the rest of formation would’ve scoff at the “fire truck”.

Yes, a variety of rotating beacons until strobes became widespread in the ‘80s. Cessnas had just a flashing light early on. The KC-135 had a huge one with various colors for signaling.

I much prefer the rapid flashing strobes vs. the sleepy pulses. The double flash strobe on the Airbuses specially.

The aggressive WHAP-WHAP really gets noticed, not to mention it looks cool too! =)

You know who prefers the LED long flash though? Despite how cool it looks? Pilots in line for takeoff at night. They aren’t nearly as blinding as the xenon strobes.