Learning to use the VASI

[Morne]

Did a night flight recently, just to keep night current for passengers. Staying in the pattern, only having to let one Citation in, I got plenty of practice using the VASI. Funny thing is, I usd to ignore them completely.

While that might sound odd, let me explain. Where I learned to fly they didn't have VASI or PAPI. Further, they taught the power-off landing (as in, cut power when abeam of the numbers) with full flaps, so we were much steeper than 3 degrees glide on final. Lastly, it was a fairly short runway (2410') so we always aimed "for the numbers" rather than for "halfway down the first third".

The few times I went to another field at night during my training I always noticed that my "normal pattern" would start with the VASI showing "too high", then "on glide" and lastly "too low" just before touchdown near the numbers. As such, I tuned them out. Sure, I knew how they worked, but from a practice standpoint they were a waste.

Now that I fly a 182, my high-performance endorsement instructor coaxed me into flying bigger patterns and being willing to use partial-power on final. I'm thrilled with the result, namely smoother landings at a more consistent touchdown point. Coincidentally, during night landings I find I'm pretty much dead on with the 3-degree glide slope that the VASI expects. So I guess the VASI is not completely useless to me anymore.

 

[zaitcev]

I had a similar evolution, only instead of 182 it was the switch to Arrow that flattened my final approach. However, even when I dive on the runways in Cherokee, VASI does not go red on me, PAPI does 2+2 as it should. I aim for the fat bars. Being a beginner I do not want to presume too much about your flying but I suspect you may be landing just a bit short.

 

[Jaybird180]

My primary instructor didn't want me to use the PAPI at my training field (also 2400') so I learned completely visual like you. I also learned partial power throughout the entire pattern.

When I got to my next CFI and night work, the PAPI began to become one of the tools that I learned to use and I doubt I'd fly at night without one at that airport.

The target for these visual glideslope instruments is usually well displaced from the runway threshold which may be contributing to your disagreement with their indication; you've learned different aiming points.

 

[CMTowner]

I never really payed attention to the vasi or papi lights during training until I started night flying, especially when flying at night solo. I really noticed how they helped out when I performed night flights to airports with no other ambient lighting around the airport. The extremely dark nights at airports that are in the country made landing without this aid more interesting, to say the least.

 

[dell30rb]

I find the vasi helpful at night

 

[HPNPilot1200]

It's so great it even has its own regulation.

14 CFR 91.129(e)(3):

Each pilot operating an airplane approaching to land on a runway served by a visual approach slope indicator must maintain an altitude at or above the glide path until a lower altitude is necessary for a safe landing.

 

[dmspilot]

It's so great it even has its own regulation.

14 CFR 91.129(e)(3):

§ 91.129 Operations in Class D airspace.

 

[HPNPilot1200]

§ 91.129 Operations in Class D airspace.

Also applicable in Class B and C airspace (91.131, 91.130).

 

[Morne]

Also applicable in Class B and C airspace (91.131, 91.130).

Sorry guys - I fly from an uncontrolled field. Frankly, I prefer it that way.

 

[TMetzinger]

And remember, since even where it's regulated, you're only required to not go BELOW the visual glideslope, those of us who fly higher and steeper power-off approaches are still just fine.

 

[p1l0t]

My style at night is this (maybe not best practice just what's become my habit); I fly the glideslope red over white equally or two white two red whatever until I know I am beyond the obstacle. Then I pull the throttle if its not already idle and aim the nose for the begining of the pavement (even if its displaced). I level off (gentle transition to a flare) in ground effect and hold off the touchdown of the mains as long as possible holding my attitude as my speed drains out. I don't touch the mains down until at least the numbers though on a displaced threshold and I will crack the throttle to cushion the landing if I think it will make it a nicer touchdown. Of course, still holding that nose up attitude even after the mains touch until there isn't even enough speed to keep the nose up anymore. The VASI or PAPI will turn red at the end but at that point I KNOW I can make a good landing so I think I'm still legal. Its a nice short landing, but you give up the nice stabilized approach that you get just flying the glideslope right to the TDZE.

<---<^>--->

 

[Fearless Tower]

And remember, since even where it's regulated, you're only required to not go BELOW the visual glideslope, those of us who fly higher and steeper power-off approaches are still just fine.

Actually, you can go below the visual glideslope as long as you are in a position to land - there is nothing wrong with touching down on the numbers or even the threshold markings as long as you are in visual conditions....on some shorter runways that may very be the best spot to touch down.

I do power off 180s at MYF all the time...runway 28R has 3400' available for landing due to an 1100' DT. I am well above the visual GS at the beginning but under it when I touch down because my intended touchdown spot is in between the edge of the threshold markings and the tops of the numbers.

Because of the runway length, even when I am arriving IFR, I will touchdown in the same spot. I fly the LOC GS and the Visual GS until I am over the beginning of the DT and then start pulling power off and adjusting my pitch to land on the numbers.

 

[kimberlyanne546]

My instructor never once taught with it, even though we had one. There are a lot of "low tech" tiny unlit airports in my area and so he did not want me to start relying on anything other than my own eyeballs.

In many ways, he was a great instructor and very wise. I use them sometimes now, and since I've flown with other pilots now they have told me how they would use them (thanks Mari on our no-flap landing when the flap motor broke and you suggested a flatter approach - the three reds and one white helped with that).

 

[dell30rb]

I was cleared straight in about 5-6 miles out to a 10,000 foot runway recently and I used the vasi for that. I flew as fast as possible (about 5 knots over cruise) until about half a mile out and then pulled all the power off, dropped flaps and landed. Took the guesswork out of an unusual approach to a runway - the size of which I had never landed upon before

 

[kimberlyanne546]

I was cleared straight in about 5-6 miles out to a 10,000 foot runway recently and I used the vasi for that. I flew as fast as possible (about 5 knots over cruise) until about half a mile out and then pulled all the power off, dropped flaps and landed. Took the guesswork out of an unusual approach to a runway - the size of which I had never landed upon before

Exactly. I will use it when things are "not normal" for me, but otherwise I try to use my own judgement.

 

[MadseasoN]

Shouldn't it depend on what you're flying?

Correct me if I'm wrong but isn't a 3 degree approach = 20:1 descent? The glideslope for a Warrior II/C172 is about 9:1 and I'm sure it's way lower for the heavier prop planes (Cherokee, etc). A 3 degree approach would put you ~300' AGL @ 1 mile from the runway. You'll never make it if the engine fails.

 

[kimberlyanne546]

Shouldn't it depend on what you're flying?

Correct me if I'm wrong but isn't a 3 degree approach = 20:1 descent? The glideslope for a Warrior II/C172 is about 9:1 and I'm sure it's way lower for the heavier prop planes (Cherokee, etc). A 3 degree approach would put you ~300' AGL @ 1 mile from the runway. You'll never make it if the engine fails.

This is in line with what my instructor taught me. In other words, they can't design a different set of lights for each aircraft, so he taught me to rely on my eyeballs and said that some of these VASI / PAPI lights were designed for larger, heavier aircraft than my tiny 152.

 

[dell30rb]

Shouldn't it depend on what you're flying?

Correct me if I'm wrong but isn't a 3 degree approach = 20:1 descent? The glideslope for a Warrior II/C172 is about 9:1 and I'm sure it's way lower for the heavier prop planes (Cherokee, etc). A 3 degree approach would put you ~300' AGL @ 1 mile from the runway. You'll never make it if the engine fails.

True, and when I fly a normal pattern during the day I ignore the VASI altogether and fly a tight pattern with a steeper approach.

However as it has been repeated engine failures are very few and far between for certificated aircraft. Pilot error is more likely to cause an accident, esp. at night. At night it can be difficult to judge your approach if you are landing on a runway that is longer or wider than what you are used to. Lots of aircraft crash on final approach at night. I feel in this case, its safer to use the VASI. Or you could tune the ILS if available.

You don't shoot an ILS approach in IMC by ignoring the (usually) 3 degree glideslope do you?

PS.. A warrior II is a cherokee

 

[MadseasoN]

True, and when I fly a normal pattern during the day I ignore the VASI altogether and fly a tight pattern with a steeper approach.

However as it has been repeated engine failures are very few and far between for certificated aircraft. Pilot error is more likely to cause an accident, esp. at night. At night it can be difficult to judge your approach if you are landing on a runway that is longer or wider than what you are used to. Lots of aircraft crash on final approach at night. I feel in this case, its safer to use the VASI. Or you could tune the ILS if available.

You don't shoot an ILS approach in IMC by ignoring the (usually) 3 degree glideslope do you?

PS.. A warrior II is a cherokee

Yes but engine failures do happen. I trust my flying skills more than I trust an engine.

OP didn't mention anything about IMC or ILS approaches. He was doing pattern work and mentioned widening his pattern. If he's on a 3 degree approach then he would be way too low on final (for a prop plane). Even at night you should be able to fly white/white and pull off a decent landing.

My mistake. I'm used to calling the Cherokee 235 a 'Cherokee' and the Warrior II the 'Warrior' since I fly both.

 

[Fearless Tower]

My mistake. I'm used to calling the Cherokee 235 a 'Cherokee' and the Warrior II the 'Warrior' since I fly both.

You need to come out to SoCal...where ATC calls everything from a PA28-140 to a Saratoga a 'cherokee'

 

[dell30rb]

Yes but engine failures do happen. I trust my flying skills more than I trust an engine.

OP didn't mention anything about IMC or ILS approaches. He was doing pattern work and mentioned widening his pattern. If he's on a 3 degree approach then he would be way too low on final (for a prop plane). Even at night you should be able to fly white/white and pull off a decent landing.

I know he didn't mention anything about ILS... but my point was that we fly 3 degree approach angles with regularity and it does not seem to be a safety concern.

 

[MadseasoN]

I know he didn't mention anything about ILS... but my point was that we fly 3 degree approach angles with regularity and it does not seem to be a safety concern.

Grab your favorite instructor and your C152 then do a deadstick landing on 1 mile final at 600'. Then try 1/2 mile final at 300'. Remember to wait a second or two to 'realize' that your engine has died.

 

[azure]

Grab your favorite instructor and your C152 then do a deadstick landing on 1 mile final at 600'. Then try 1/2 mile final at 300'. Remember to wait a second or two to 'realize' that your engine has died.

Right, if you always fly the approach power-off then the VASI glideslope is too shallow. If you always fly the approach power off because you're afraid of losing an engine, well fine, but that isn't what the FAA recommends, and there are lots of situations where it's just unsafe to fly that way. The example of an ILS that someone gave is one. VASI, ILS, LPV glideslopes all require power-on stabilized approaches in any piston single that I'm aware of -- and that's the way the FAA says we should be flying on final approach.

And -- there are runways where I will not land at night if the PAPI/VASI is OTS. I took a good tongue-lashing from the owner one time at 76G for landing downwind at night on 22 because the PAPI on 04, with power lines about 200 AGL 1/4 mile from the threshold, was OTS indefinitely. (Bill had accidentally dug up the power cable to the PAPI and now relied on a homebrew timed approach to get in at night on runway 4. He tried to teach it to me. No thanks -- with a strong enough headwind it would be easy to wind up in those P-lines.)

 

[Morne]

I know he didn't mention anything about ILS... but my point was that we fly 3 degree approach angles with regularity and it does not seem to be a safety concern.

While I didn't mention anything about ILS, the instructor who taught me to open up my pattern knew that I'd be working on my instrument rating next. He also knew that I had the power-off, full-flaps, steep descent approach well memorized and wanted to show me another technique. I happen to like this technique better, ESPECIALLY at night.

Now that I am sometimes flying with passengers it is easier to make a nice landing with a more open pattern and 3-degree final. I want them to fly with me again...

 

[p1l0t]

Another thing pilots can do is not put the flaps in until they are already too high and fast even at idle. It avoids "pressing the gas and the brake at the same time" and gives you the ability to fly a decent at shallower angle. Not saying its a 'best practice,' just that it helps to alivate droping into the trees if the power is idle and with still something left to slow you down or steepen the descent. Nothing wrong with throwing that last notch in over the fence.

<---<^>--->

 

[Morne]

Nothing wrong with throwing that last notch in over the fence.

While I agree, the DPE I did my PPL checkride with was quite vocal that such a practice is less than optimum. Didn't fail me for it, but he certainly expressed his displeasure. During debrief he hammered on "stabilized approach" and said that if you're still playing with flaps then your approach is not stable. He insisted that if you have to adjust anything on final it should be throttle only; if for no other reason than your hand should be on it anyway in case of a go around.

Just like everything else, from glide slopes to using VASIs, opinions vary.

 

[MadseasoN]

Right, if you always fly the approach power-off then the VASI glideslope is too shallow. If you always fly the approach power off because you're afraid of losing an engine, well fine, but that isn't what the FAA recommends, and there are lots of situations where it's just unsafe to fly that way. The example of an ILS that someone gave is one. VASI, ILS, LPV glideslopes all require power-on stabilized approaches in any piston single that I'm aware of -- and that's the way the FAA says we should be flying on final approach.

And -- there are runways where I will not land at night if the PAPI/VASI is OTS. I took a good tongue-lashing from the owner one time at 76G for landing downwind at night on 22 because the PAPI on 04, with power lines about 200 AGL 1/4 mile from the threshold, was OTS indefinitely. (Bill had accidentally dug up the power cable to the PAPI and now relied on a homebrew timed approach to get in at night on runway 4. He tried to teach it to me. No thanks -- with a strong enough headwind it would be easy to wind up in those P-lines.)

Eh, the rule has been posted here. I'm not aware of any other recommendation.

I agree on some points since the answer to every aviation question is "it depends". Do what you think is safest. Barring any emergency situation I think I'll stick with my 500' per 1/2 mile descent profile.

18:1 is right under 3 degrees. 500' per 1/2 mile is almost double that.

76R Runway 4:
Obstructions: 100 ft. pline, 2000 ft. from runway, 18:1 slope to clear

 

[Fearless Tower]

While I agree, the DPE I did my PPL checkride with was quite vocal that such a practice is less than optimum. Didn't fail me for it, but he certainly expressed his displeasure. During debrief he hammered on "stabilized approach" and said that if you're still playing with flaps then your approach is not stable. He insisted that if you have to adjust anything on final it should be throttle only; if for no other reason than your hand should be on it anyway in case of a go around.

Just like everything else, from glide slopes to using VASIs, opinions vary.

Hell, I've been known to go from zero to full flaps inside the fence.......but that is a special circumstance.

 

[jesse]

My instructor never once taught with it, even though we had one. There are a lot of "low tech" tiny unlit airports in my area and so he did not want me to start relying on anything other than my own eyeballs.

In many ways, he was a great instructor and very wise. I use them sometimes now, and since I've flown with other pilots now they have told me how they would use them (thanks Mari on our no-flap landing when the flap motor broke and you suggested a flatter approach - the three reds and one white helped with that).

I really don't understand why an instructor wouldn't teach the student how they work. In fact, it's their duty to do so. It offers some pretty immense safety benefits, especially at night. It's not like you can block the student from seeing the thing.

The student will learn to land without it when you take them to an airport that doesn't have one (which I always do).

 

[kimberlyanne546]

I really don't understand why an instructor wouldn't teach the student how they work. In fact, it's their duty to do so. It offers some pretty immense safety benefits, especially at night. It's not like you can block the student from seeing the thing.

The student will learn to land without it when you take them to an airport that doesn't have one (which I always do).

Probably because it was covered in the written test.

 

[HPNPilot1200]

I really don't understand why an instructor wouldn't teach the student how they work. In fact, it's their duty to do so. It offers some pretty immense safety benefits, especially at night. It's not like you can block the student from seeing the thing.

The student will learn to land without it when you take them to an airport that doesn't have one (which I always do).

It's actually one of the things I explain during the first few hours of primary training. I find it helps students very much when they understand how they can use it to fly a stabilized approach.

Probably because it was covered in the written test.

It may be depending on which questions you get, but no guarantee. Learning how to use it in the airplane is also different than reading about it in a book IMO. I never really understood what a P-VASI looked like from the airplane until I used the one at LWV last year.

 

[Matthew]

My CFI made sure I always used VASI or PAPI lights whenever they were available. There are enough places that don't have them, so you might as well get used to the sight picture of what a controlled approach looks like. And by controlled approach, I mean one with some feedback - that way, when you are training yourself to know what "that looks about right" looks like, you have something known to compare it against. I prefer using them at any airport that has them, especially airports where I haven't landed before.

 

[dell30rb]

Grab your favorite instructor and your C152 then do a deadstick landing on 1 mile final at 600'. Then try 1/2 mile final at 300'. Remember to wait a second or two to 'realize' that your engine has died.

I never disputed that... I've done enough power off landings to know very well that if your engine fails you're not going to maintain a 3 degree GS in a c152.. or many other types for that matter.

My point was that, at night when approaching an unfamiliar airport I think using the VASI is prudent. It will help keep you away from obstacles and help you to make a smooth landing. if you overshoot may run into trouble - you can't see the trees at the other end of the field - and you may not be able to see the threshold lights at the other end if the runway has a hump in the middle

We've all read about how runways of different lengths and widths can give you an illusion of being too high or too low, esp. at night. Its additionally hazardous when you cannot see the trees around the airport

 

[MadseasoN]

I never disputed that... I've done enough power off landings to know very well that if your engine fails you're not going to maintain a 3 degree GS in a c152.. or many other types for that matter.

My point was that, at night when approaching an unfamiliar airport I think using the VASI is prudent. It will help keep you away from obstacles and help you to make a smooth landing. if you overshoot may run into trouble - you can't see the trees at the other end of the field - and you may not be able to see the threshold lights at the other end if the runway has a hump in the middle

We've all read about how runways of different lengths and widths can give you an illusion of being too high or too low, esp. at night. Its additionally hazardous when you cannot see the trees around the airport

I guess you threw me off with this:

"...but my point was that we fly 3 degree approach angles with regularity and it does not seem to be a safety concern. "

For me "regularity" isn't landing at night at an unfamliar airport.

I would still only be concerned with staying above the red. A more shallow approach will cause you to use more runway, not less. You should be familiar enough with your aircraft to know what your rollout will be.

 

[denverpilot]

While I agree, the DPE I did my PPL checkride with was quite vocal that such a practice is less than optimum. Didn't fail me for it, but he certainly expressed his displeasure. During debrief he hammered on "stabilized approach" and said that if you're still playing with flaps then your approach is not stable. He insisted that if you have to adjust anything on final it should be throttle only; if for no other reason than your hand should be on it anyway in case of a go around.

Just like everything else, from glide slopes to using VASIs, opinions vary.

"Stabilized Approach" has been the "hard-on du jour" since I came back to flying after eight years away. It has lasted longer than some others, mostly because it sounds like something jet crews do.

Of course, jets have to do it, with long spool up times, and various other reasons... but it's now "stuck" in the propeller-driven world, and people fly 3 degree glideslopes from 10 miles out all the time now, dragging themselves to the airport with power.

I have no problem with that, the problem I have is they don't learn the OTHER ways to safely get to the airport. The high-and-tight pattern with power virtually all the way off after turning base... all techniques they should know to be well-rounded pilots...

When I left flying, the Pet Peeve then was "Tune and Identify". I guess the advent of the GPS is slowly destroying that one.

The Pet-Peeve of the Decade, changes every decade or so...

The safest is to know how to fly ALL of those ways, and to conform to the Pet Peeve when required. But barring that, with little experience, fly the pet peeve method of the week unless you feel like arguing that day.

 

[Fearless Tower]

A more shallow approach will cause you to use more runway, not less.

Only if your speed is too fast.

 

[Fearless Tower]

"Stabilized Approach" has been the "hard-on du jour" since I came back to flying after eight years away. It has lasted longer than some others, mostly because it sounds like something jet crews do.

And as you pointed out jets are the exact reason that the 'stabilized' approach was created.

 

[dell30rb]

I have no problem with that, the problem I have is they don't learn the OTHER ways to safely get to the airport. The high-and-tight pattern with power virtually all the way off after turning base... all techniques they should know to be well-rounded pilots...

Believe me I am not suggesting anyone start dragging approaches in from ten miles out.

My preferred daytime approach at an uncontrolled airport is a tight pattern with a full flaps (in the piper, 20 degrees in the cessna) nearly power off final at 65 knots slowing to just above 60 over the fence. If I'm solo sometimes that turns into staying at pattern altitude until I turn final then full flaps and full slip 100 knots dropping like a rock final approach, holding the slip in 10 feet off the runway until you bleed off some speed, then remove the slip, flare and touchdown. If traffic and weather permits I love to play around with the airplane as much as anyone else.

At night I fly a normal pattern except final approach is a bit shallower. 1.3 Vso with full flaps and adjust power to stay on the VASI glideslope. Once my landing light picks up the runway and I know I'm "over the fence", pull the power all the way off and set her down. A no-fuss, safe and smooth way to fly approaches at night.

Of course I don't rely so much on the vasi to where I could not make a night approach without one. My best guess is probably pretty good but I like having the vasi available. I try very hard not to make a night landing at a small airport I have never been to at night. If I know i'm going to be making a night landing I'll try to pick a 3500'+ public runway that I know is used frequently, well lit and the notams / obstructions are up-to-date. Does not hurt if it has a papi/vasi

For me "regularity" isn't landing at night at an unfamliar airport.

I've been caught by weather delays, passenger delays etc.. and made several unplanned night landings. Its good to approach a night landing at an unfamiliar airport in a pre-planned, controlled and familiar fashion.

 

[jesse]

It's actually one of the things I explain during the first few hours of primary training. I find it helps students very much when they understand how they can use it to fly a stabilized approach.

As do I. In fact I bring it up on the first lesson when I'm walking them through the landing.

 

[MadseasoN]

I've been caught by weather delays, passenger delays etc.. and made several unplanned night landings. Its good to approach a night landing at an unfamiliar airport in a pre-planned, controlled and familiar fashion.

Riiigghhht.