PAPI/VASI Obstruction Clearance

[TxFlight]

Hey Guys and Gals,

I'm a little confused by VASI 4nm obstruction clearance
and PAPI 3.4nm obstruction clearance.

Is that translated to;
You're guaranteed obstacle clearance 4/3.4 miles prior to touchdown or you're guaranteed obstacle clearance until you're 4/3.4 miles prior to the touchdown?

If it's the later, is that the time to disregard the VASI/PAPI and focus on the aiming points for the runway?

On a side note, I couldn't imagine an obstruction being 4 miles prior to or beyond touchdown that would be in conflict with "on glide path" visual aids so that's why it's not making sense to me. I can't think of any airport that you would be 10 miles out on red white glide path and hit something.

 

[MikeD]

Guaranteed when inside those distances.

For your side note, an example airport would be KRNO, Rwy 25, with this notation appended to it:

PAPI NOT TO BE USED BEYOND 2 NM DUE TO RAPIDLY RISING MOUNTAINOUS TERRAIN

 

[TxFlight]

Thanks a lot Mike!

"Knowing is half the battle" ~ GI Joe

 

[Bandit_Driver]

I think ROA has similar issues to one of the runways. IF on the PAPI/VASI you will be on GP and the runway will disappear behind the mountain...

 

[deadstick]

NOTES — read them from start to finish.

Also the NOTAMs. If the visual glidepath indicator is inop, night landings might be NA due to obstacles penetrating the 20:1 OIS.

 

[Cessnaflyer]

I think Molokai had a distance limitation. I don’t think I was ever more than a mile away from the runway though and we couldn’t go in after sunset IIRC.

 

[MikeD]

Yes 25 is a tricky landing at RNO, but a nice option to have with the constant high crosswinds there. Just tough to do a straight in to it in a larger aircraft and still remain stable. Short base much easier.

 

[Richman]

I thought obstruction clearance was when I have a banana with my morning coffee.

 

[TxFlight]

Thank everyone for the insight. Now I will fly the visual aids with confidence! Safe flying y'all!

 

[Autothrust Blue]

I thought obstruction clearance was when I have a banana with my morning coffee.

Steel-cut oats, dried fruit, bananas, probiotics and a cup of coffee. @Derg

 

[Richman]

Steel-cut oats, dried fruit, bananas, probiotics and a cup of coffee. @Derg

My cats love stinky stuff like all cats do, but even considering that they'd go "Dude, something is wrong with you. Better get that checked."

 

[Autothrust Blue]

My cats love stinky stuff like all cats do, but even considering that they'd go "Dude, something is wrong with you. Better get that checked."

Ha! I mean, if all of the above don’t work there certainly is something wrong.

 

[Oxman]

Steel-cut oats, dried fruit, bananas, probiotics and a cup of coffee. @Derg

Then stuck in morning traffic! Good times.

 

[MidlifeFlyer]

I think ROA has similar issues to one of the runways. IF on the PAPI/VASI you will be on GP and the runway will disappear behind the mountain...

A good number of airports in mountainous areas have that issue.

 

[derg]

So what does your cat do, @Autothrust Blue? Oh yeah, you never got off your butt and got one. RECTIFY THIS!!!

 

[Autothrust Blue]

So what does your cat do, @Autothrust Blue? Oh yeah, you never got off your butt and got one. RECTIFY THIS!!!

When I get one I assume they'd stare coldly into my eyes as I enjoy my morning download in an attempt to establish alpha.

 

[Autothrust Blue]

Even though they are the perfect airline animal, I don't feel good about leaving them home alone for days on end. And I live alone, so.

 

[killbilly]

Even though they are the perfect airline animal, I don't feel good about leaving them home alone for days on end. And I live alone, so.

This is why you get two. Seriously.

 

[Cessnaflyer]

This is why you get two. Seriously.

Then you come home to boxes of cement with fecal surprises and the odor of feline urine everywhere.

 

[Richman]

Even though they are the perfect airline animal, I don't feel good about leaving them home alone for days on end. And I live alone, so.

Mine are totally fine with it. When I get home they barely look up other than to say “ah, hoomin, you’re back. Clean tha’ sandbox. K thx.”