Strobes / Anti collision lights

[One9iner]

Chaps...

Sorry to ask a queston for what may require an obvious answer.

Where I live, I see LHR arrivals for 27's roll in every few minutes. Now it's getting dark early, it's become more obvious how different aircraft flash their strobes and anti-collisions lights at different rates.

Some aircraft seem to strobe, at no direct frequency to anti collision lights.. however I saw an a340 roll in last night with strobes and red anti collision lights flashing at the same time...

Is there a link? Pattern? Specific to type/size?

Many thanks to a confused onlooker:ouch:

[wobble2plank]

I have to ask, why does it matter? Next time I do a walkround with the strobes on test I'll time them! :ugh:

In all honesty no, there is no 'set' pattern. The strobes operate on a capacitive discharge so I would assume, dependent upon age and state, that they discharge whenever they reach that specific charge. The 'beacon' is switched on at push back and is on whenever the engines are running or the aircraft is moving. The strobes are normally switched on upon runway entry but in the 'auto' position they will activate when the weight in wheels switch becomes active at rotate.

I do know that Airbus generally tend to use double flash on the wing and Boeing use a single flash but none are 'timed' as far as I know.

[spannersatcx]

Airbus 340:
The aircraft recognition system consists of two independent systems which are designed to operate alternately in synchronization:
- anti-collision light system,

- strobe light system,

The two anti-collision lights flash at a rate of 60 +/- 10 flashes per minute.

All strobe lights flash at a rate of 60 +/- 10 flashes per minute. Additionally a second flash tube in the forward facing strobe lights flashes at a rate of 60 +/- 10 flashes per minute. This produces 120 +/- 20 flashes per minute in the forward direction and 60 +/- 10 flashes per minute in the rearward direction.

Boeing 744 there is no synchronisation between strobes and beacons.