B777LRF From Luxembourg, joined Nov 2008, 1006 posts, RR: 3 Reply 2, posted (1 year 10 months 3 weeks 2 days 18 hours ago) and read 2993 times:
Nothing at all to do with controllers, but it is grounded in safety. It's about visual recognition at night by other aircraft, and tests have shown that a double-flash strobe is recognised faster and more often than a single flash. Simple as that.
It's not only Airbus using those strobes, it's a quite popular option on very many business jets as well. Can't recall if any of the other airline manufacturers (BCA, BBD, EMB, SUK etc.) are using single or double flash as standard, or if it's available as an option.
From receips and radials over straight pipes to big fans - been there, done that, got the hearing defects to prove
cloudboy From United States of America, joined Jan 2004, 668 posts, RR: 0 Reply 3, posted (1 year 10 months 3 weeks 2 days 18 hours ago) and read 2941 times:
You see it on plice cruisers and other emergency vehicles as well.
"Six becoming three doesn't create more Americans that want to fly." -Adam Pilarski
SPREE34 From United States of America, joined Jun 2004, 2096 posts, RR: 10 Reply 6, posted (1 year 10 months 3 weeks 2 days 8 hours ago) and read 2448 times:
DC-10 is the first I saw it on, and that was 1972.
I don't understand everything I don't know about this.
AA737-823 From United States of America, joined Mar 2000, 5340 posts, RR: 11 Reply 7, posted (1 year 10 months 3 weeks 2 days 6 hours ago) and read 2405 times:
Some of the Gen-Av planes do three flashes... gets kinda annoying!
I'm not sure that it's two separate bulbs, either.... It could be, but the ones I've seen weren't.
SPREE34 From United States of America, joined Jun 2004, 2096 posts, RR: 10 Reply 8, posted (1 year 10 months 3 weeks 2 days 6 hours ago) and read 2385 times:
Quoting AA737-823 (Reply 7): I'm not sure that it's two separate bulbs, either.... It could be, but the ones I've seen weren't.
You are correct. 1 bulb. By design, the first flash is highest intensity, the next 2 are at a lower intensity. The same system is found in some GA anti-collision strobe lights. (red beacon)
I don't understand everything I don't know about this.
The only big airliner I remember, was the MD-11 which had it as well...
DC-10, MD-10, & Super 80s do this too.
Quoting SPREE34 (Reply 8):
You are correct. 1 bulb. By design, the first flash is highest intensity, the next 2 are at a lower intensity. The same system is found in some GA anti-collision strobe lights. (red beacon)
It isn't so much by design, just that the capacitors haven't had time to fully charge up again between the first and second flashes, hence the first one being more intense.
SPREE34 From United States of America, joined Jun 2004, 2096 posts, RR: 10 Reply 10, posted (1 year 10 months 3 weeks 2 days 5 hours ago) and read 2364 times:
It's an optical illusion on the 80. The forward facing strobe only fires once, yet fro some angles one can see the rearward strobe flash as well, giving the double flash impression. It's not intentional, and the forward and rearward are not sequenced. You'll see this on the E170/75 and 190/95 as well.
I understand the capacitor theory. Makes sense. I was told it's by design by a Wheelen rep. Something to do with involuntary eye movement and following movement. Whatever, I didn't sleep at Holiday Inn last night.
I don't understand everything I don't know about this.
shamrock137 From United States of America, joined Jul 2005, 79 posts, RR: 0 Reply 11, posted (1 year 10 months 3 weeks 2 days 5 hours ago) and read 2362 times:
Another aspect of the Airbus design is it makes it easier to tell which direction the aircraft is facing. The double flash is only in the forward facing wingtip strobes while the aft facing strobe is a single flash.
747fan From United States of America, joined Jun 2007, 1165 posts, RR: 1 Reply 12, posted (1 year 10 months 3 weeks 2 days ago) and read 2294 times:
I'm not sure about improved safety, but it definitely makes it easier at night to identify aircraft - I can almost always tell its an Airbus, or at least narrow it down among bigger aircraft to an Airbus or DC-10/MD-11.
But my guess as to why they have two strobes is due to redundancy. For example, the L-1011 had two different anti-collision lights/beacons on both the top & bottom of the fuselage - from what I've read this was for redundancy purposes. One of the strobes/beacons could be "MEL'ed." I suppose this is the same for the Airbus wingtip strobes. Interestingly, just like the L-1011, the A380 has 2 separate anti-collision strobes on the top & bottom of the fuselage (usually its just 1).
Quoting wn700driver (Reply 9): The only big airliner I remember, was the MD-11 which had it as well...
DC-10, MD-10, & Super 80s do this too.
Indeed, except for the Super 80. Also I believe the L-1011 had double wingtip strobes. However, the earlier A300's (A300B2/B4) don't have the double flash sequence.
I'll add that most, if not all of Fed Ex's 727's have the double flash sequence - I'm guessing this was a modification FX did to these aircraft. Interestingly, I've noticed FX A306's/A310 that do NOT have the double strobes (its an interesting sequence where the strobes alternate between the left & right wing, much like the ERJ-145).
wn700driver From , joined Dec 1969, posts, RR: Reply 13, posted (1 year 10 months 3 weeks 1 day 23 hours ago) and read 2265 times:
Quoting SPREE34 (Reply 10):
It's an optical illusion on the 80. The forward facing strobe only fires once, yet fro some angles one can see the rearward strobe flash as well, giving the double flash impression. It's not intentional, and the forward and rearward are not sequenced. You'll see this on the E170/75 and 190/95 as well.
Quoting 747fan (Reply 12):
Indeed, except for the Super 80.
Yeah, I was wrong about that. I took a closer look at those out on the ramp, they don't have it.
Quoting SPREE34 (Reply 10):
I understand the capacitor theory. Makes sense. I was told it's by design by a Wheelen rep. Something to do with involuntary eye movement and following movement. Whatever, I didn't sleep at Holiday Inn last night.
I don't see that it would be a mutually exclusive thing... I know capacitors definitely work that way, but it could still very well be that the sequence was also designed with that in mind instead of a longer sequence...
Quoting 747fan (Reply 12):
I'll add that most, if not all of Fed Ex's 727's have the double flash sequence - I'm guessing this was a modification FX did to these aircraft.
There's an FX that heads eastbound most nights from AFW, and passes over us at DFW, usually around AM2 or 3, and usually not more than about 3000 or 4000 agl... I have certainly noticed this as well...
navion1217 From United States of America, joined Jul 2010, 19 posts, RR: 0 Reply 14, posted (1 year 10 months 3 weeks 1 day 21 hours ago) and read 2231 times:
For GA airplanes, Whelen had a "cometflash" strobe which would flash 3 or 4 times. I think the Pulselight on landing lights is a better thing. I wish all the motorcycles here in Daytona would have it.
Sponsor Message: 
From Germany, joined Mar 2005, 1018 posts, 
From Luxembourg, joined Nov 2008, 1006 posts, 
From United States of America, joined Jan 2004, 668 posts, 
From United Kingdom, joined Sep 2003, 9112 posts, 
Sponsor Message: 
Printer friendly format
