Rwy lights = 1/4 sm

[matthewjohn]

How many runway edge lights do you have to see to = 1/4 mile vis. saying you are sitting on the numbers?

 

[CA1900]

Well, the lights are spaced 200 feet apart. 1 statute miles is 5280 feet. You do the math.

 

[HS125]

How many runway edge lights do you have to see to = 1/4 mile vis. saying you are sitting on the numbers?

1/4 mile is considered to = 1600 RVR (feet). Assuming that the runway lights are spaced every 200 feet, you should be able to see at least 8 runway lights on each side of the runway at 1/4 mile vis.

 

[Flysher]

Yeah I wondered this before too. Ive done takeoffs at 1/4 but its never been that far, makes you wonder how accurate the vis meter is.

 

[pilotyip]

I assume this address lower than STD takeoff mins? If the prevailing weather for your runway is given as a 1/4 mile you are good to go. The only exception would be if the runway has RVR and it is below 1600. In this case pick another runway that doesn’t have RVR. If there is no reported weather at the airport, ¼ statue mile =’s 1,320’, 6 lights, not counting the one off of your wingtip. All you will need is a reference for runway alignment, such as center marking, runway lights, etc. and you are good to go.

 

[Doc Holiday]

To add to yip's post, how many lights you can see is irrelevant. All that matters legally is what the reported visibility is. For example, if the tower is reporting 1/8sm and you see 800 lights from the end of the runway, you cannot legally go. On the other hand if the tower is reporting 2sm and you get to the end of the runway and see two lights you ARE legal to go....but it is most likely not the best idea.

Just to be specific, I believe it is RVV that is referred to in the books, not to be confused with tower visibility.

 

[pilotyip]

Doc is correct, but often if the tower is in operation you can make a PIREP and they may amend the prevailing visibility. Remains me of an incident I had at PIT back in 1978 while flying the beloved L-188 on Emery Contract for TransAmerica. The Capt loved to pad the block time, the tower was reporting 0/0, but the new runway up on the hill, 28R I believe, was reporting RVR 6000. Capt said I need the RW down in the valley where the wx was below T/O mins, we sat there with the engines running for 1.5 hours, for our .5 flight to DAY.