Interview Question

[arewethereyet]

If you have three runway stripes in sight, what is the visibility?

 

[mosyslack]

600 RVR I do believe

 

[JustInfo]

Yup, 120 foot stripes + 80 feet between = 600RVR.

 

[arewethereyet]

Thanks

 

[Cavpilot]

Yup, 120 foot stripes + 80 feet between = 600RVR.

Incorrect! The answer is 600 feet. RVR is an instrumentally derived value that represents the horizontal distance a pilot may see down the runway. So unless your eyeball somehow qualifies as a transmissometer you cannot determine RVR from the cockpit, only ground visibility.

 

[glasspilot]

It's a trick question. How far from the runway are you?

 

[JustInfo]

Cavpilot is correct, it is feet not RVR. So sorry for my incompetence...

Glasspilot - good point, hopefully they aren't using this to determine flight visibility, that is a trick question. At NJA we use this to decide if we have the 600 FEET of visibility required for takeoff, so we are hopefully sitting on the runway when we determine this, not at minimums in flight.

 

[mosyslack]

Incorrect! The answer is 600 feet. RVR is an instrumentally derived value that represents the horizontal distance a pilot may see down the runway. So unless your eyeball somehow qualifies as a transmissometer you cannot determine RVR from the cockpit, only ground visibility.

Sorry, I misspoke/typed, whatever. Interestingly enough, my eyes have been certified by the FAA as transmissometers! I also have calibrated elbows that substitute for a torque wrench. Cool...

 

[ratherfish]

1/8th mile

 

[Sparse]

So what's the point of the question? If RVR is the controlling value, who cares if you can calculate how many feet you can see. Besides, you need more than one RVR to takeoff anyway if the vis is that low. How would you eyeball roll out vis? This qualifies as a stupid interview question.

 

[Southern Cross]

So what's the point of the question? If RVR is the controlling value, who cares if you can calculate how many feet you can see. Besides, you need more than one RVR to takeoff anyway if the vis is that low. How would you eyeball roll out vis? This qualifies as a stupid interview question.

It's possible that a set of ops specs may require something more restrictive then say 0/0 for departures under part 91, hence the need to determine a visibility out of podunk airport (insert fractional operations here).

Other factors would need to be taken into effect to use this method though i.e. if your sitting on the end of the runway, the length of the runway end strips, the length of the numbers, whether it's a (L)eft, (R)ight runway (additional markings prior to strips), etc.

I have also heard this topic has been used as an interview question. Personally, I'd have to be pretty desperate to move an airplane to use this method for determining visibility.